The primary analysis of the SELECT randomized clinical trial suggests that semaglutide reduced the rates of cardiovascular (CV) death, myocardial infarction, and stroke in patients with established CV disease (CVD) and overweight or obesity without diabetes. However, the effect of semaglutide on hospitalizations in this population remains unknown. To determine the impact of semaglutide on total hospital admissions and duration of hospital stay. The SELECT trial included patients aged 45 years or older with established CVD and a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 27 or higher without diabetes at 804 clinical settings across North America, South America, Europe, Asia, Africa, and Australia. Patients were randomized from October 2018 to March 2021. This prespecified exploratory analysis was conducted from February 2024 to September 2025. Once-weekly subcutaneous semaglutide, 2.4 mg, or placebo. The total number of hospital admissions and days in hospital between the semaglutide and placebo groups. A total of 17 604 patients (median [IQR] age, 61.0 [55.0-68.0] years; 4872 female patients [27.7%]; median [IQR] BMI, 32.1 [29.7-35.7]) were followed up for a median (IQR) period of 41.8 (33.0-47.0) months. There were 11 287 hospital admissions. The number of total hospitalizations was lower in the semaglutide group vs placebo for any indication (18.3 vs 20.4 admissions per 100 patient-years; mean ratio [MR], 0.90; 95% CI, 0.85-0.95; P < .001) and for serious adverse events (15.2 vs 17.1 admissions per 100 patient-years; MR, 0.89; 95% CI, 0.84-0.94; P < .001). The number of days hospitalized for any indication per 100 patient-years was lower in the semaglutide group vs placebo (157.2 vs 176.2 days; rate ratio [RR], 0.89; 95% CI, 0.82-0.98; P = .01), as well as hospitalizations for serious adverse events (137.6 vs 153.9 days; RR, 0.89; 95% CI, 0.81-0.98; P = .02). No heterogeneity was observed for the reduction of hospital admissions with semaglutide in selected subgroups, including BMI, age, and sex. In this prespecified exploratory analysis of the SELECT randomized clinical trial, the trial cohort had a high rate of hospital admissions. Treatment with once-weekly semaglutide was associated with significant reductions in hospital admissions and overall time spent in hospital, extending its benefits beyond CV risk reduction. ClinicalTrials.gov Identifier: NCT03574597

Acute and chronic SGLT-2 inhibition increase endogenous glucose production (EGP). However, the organ - liver versus kidney - responsible for the increase in EGP has not been identified. 20 T2DM and 12 NGT subjects received [3-3H]-glucose infusion (to measure total EGP) in combination with arterial and renal vein catheterization and PAH infusion for determination of renal blood flow. Total EGP, net renal arteriovenous balance, and renal glucose production were measured before and 4 hours after dapagliflozin and placebo administration. Following DAPA, EGP increased in both T2D and NGT from baseline to 240 minutes, while there was a significant time-related decrease after placebo in T2D. Renal glucose production at baseline was <5% of basal EGP in both groups and did not change significantly following DAPA in either NGT and T2D. Renal glucose uptake (sum of tissue glucose uptake plus glucosuria) increased in both T2D and NGT following DAPA (P<0.05 vs placebo). The increase in RGU was entirely explained by the increase in glucosuria. Single dose of dapagliflozin significantly increased EGP, which primarily is explained by an increase in hepatic glucose production, establishing the existence of a novel renal-hepatic axis.

Abstract Disclosure: G. Le: None. S. Pinkson: None. J. Trejo: None. D. Tripathy: None. There is differential effect of long-term Estrogen and Testosterone therapy on lipid profile. While oral estradiol therapy in post-menopausal women has been associated with increased serum triglyceride and HDL, testosterone therapy in hypogonadal men decreases total cholesterol, LDL and HDL cholesterol. However, the long-term effects of Estrogen and Testosterone on lipid profile in transgender patients are not clear. We conducted a retrospective study to analyze the long-term effects of GAHT in transgender men and women followed in Endocrinology Clinic at Veterans Affairs Hospital. 36 transgender men (age 38 ± 2 years, on IM Testosterone cypionate) and 54 transgender women (age 46 ± 2 years, 36 on E2 tablet, 12 on patch, 6 on IM) were followed for 46 ± 5 months and 61 ± 5 months, respectively. Total cholesterol, triglyceride, HDL, LDL cholesterol, systolic and diastolic blood pressures, and BMI were compared before and after initiation of therapy. As expected, following GAHT, total testosterone was higher (546 ± 48 vs. 35 ± 9 ng/dL, P<0.001) in transgender men; in transgender women, serum E2 was higher (110 ± 9 vs. 26 ± 2 pg/dL, P<0.001) and total testosterone was suppressed (444 ± 29 ng/dL vs. 66 ± 13 ng/dL). In transgender men, after a follow-up period of approximately 4 years, there were no significant changes in lipid profile (total cholesterol 178 ± 8 vs. 175 ± 8 mg/dL, triglyceride 121 ± 4 vs 134 ± 12 mg/dL, HDL 47 ± 2 vs. 44 ± 2 mg/dL, LDL 107 ± 7 vs. 106 ± 8 mg/dL, all p=NS). Similarly in transgender women, no difference in lipid profile (total cholesterol 170 ± 5 vs. 175 ± 4 mg/dL, triglyceride 118 ± 7 vs 140 ± 9 mg/dL, HDL 49 ± 2 vs. 53 ± 3 mg/dL, LDL 99 ± 4 vs. 97 ± 4 mg/dL, all p=NS) was observed after 5 years of GAHT. There were no differences in lipid profile regardless of E2 tablet, patch or IM therapy. In transgender men, there was an increase in diastolic blood pressure (72 ± 3 vs. 76 ± 2 mmHg, P<0.05) while in transgender women there was decrease in systolic blood pressure (124 ± 2 vs. 118 ± 2 mmHg, p<0.005), and slight increase in BMI (28 ± 0.9 vs. 30 ± 1 kg.m2, P<0.005). In conclusion, long-term testosterone therapy in transgender men and estrogen therapy in transgender women was not associated with worsening lipid profile. Estrogen therapy was associated with lower BP in transgender women and testosterone therapy led to higher BP in transgender men. Presentation: 6/2/2024

Background and aims: Hyperglucagonemia is a characteristic feature of type 2 diabetes mellitus (T2DM). We examined the effect of chronic (48-72 h) physiologic increase (+50 mg/dl) in plasma glucose concentration on suppression of plasma glucagon concentration by insulin and by hyperglycemia in normal glucose tolerance (NGT) individuals. Materials and methods: Study One: 16 NGT subjects received OGTT and 3-step hyperinsulinemic (10, 20, 40 mU/ m(2)center dot min) euglycemic clamp before and after 48 hour glucose infusion to increase plasma glucose by similar to 50 mg/dl. Study Two: 20 NGT subjects received OGTT and 2-step hyperglycemic (+125 and + 300 mg/dl) clamp before and after 72 hour glucose infusion. Plasma insulin, C-peptide and glucagon concentrations were measured during OGTT, euglycemic hyperinsulinemic and hyperglycemic clamps. Ratio of plasma glucagon/insulin was used as an index of insulin-mediated suppression of glucagon secretion. Results: During all 3 insulin clamp steps (Study 1), plasma glucagon concentration was increased compared to baseline study, and plasma glucagon/insulin ratio was significantly reduced by 24 % (p < 0.05). The rate of insulin-stimulated glucose disposal was inversely correlated with plasma glucagon/insulin ratio (r = -0.44, p < 0.05) and with glucagon AUC (r = -0.48, p < 0.05). During the 2-step hyperglycemic clamp (Study 2) plasma glucagon was similar before and after 72 h of glucose infusion; however, glucagon/insulin ratio was significantly reduced (p < 0.05). Incremental area under plasma insulin curve during the first (r = -0.74, p < 0.001) and second (r = -0.85, p < 0.001) hyperglycemic clamp steps was strongly and inversely correlated with plasma glucagon/insulin ratio. Conclusion: Sustained (48-72 h) physiologic hyperglycemia (+50 mg/dl) caused whole body insulin resistance and impaired insulin-mediated suppression of glucagon secretion, suggesting a role for glucotoxicity in development of hyperglucagonemia in T2DM.

Aim: To examine the effect of ketogenic diet in T2D patients on glucose tolerance, beta cell function, insulin sensitivity and body fat content. Methods: 29 T2D subjects were randomized to receive for 10 days a weight maintaining diet containing: GROUP I - 30% protein, 50% CHO, 20% fat (n=8); GROUP II - isocaloric ketogenic diet with 15% protein, 5% CHO, 80% fat (n=10); GROUP III - isocaloric ketogenic diet plus ketone ester of β-OH-B, 8 grams every 8h (n=11). Subjects ate breakfast daily in the TDI Metabolic Kitchen and picked up food for lunch and dinner. Results: After 10 days, body weight remained constant: Group I (89.0 vs 89.0 kg), II (93.0 vs 92.5) and III (96.0 vs 97.0), as did body fat content. HbA1c and fructosamine did not change in any of the 3 groups. During OGTT, FPG, 2-h PG, mean PG, fasting PI, mean PI, [Delta]I/[Delta]G, and Matsuda index of insulin sensitivity did not change in Groups I, II, III. Subjects received a 2-step euglycemic insulin clamp (20 and 60 mU/m2.min) with 3-3H-glucose and indirect calorimetry. Before and after 10 days basal HGP and suppression of HGP (step I) were similar in all 3 groups. Insulin-stimulated glucose disposal (step 2) did not change in group I (4.23 vs 4.38 mg/kg.min), II (3.62 vs 3.55), or III (3.26 vs 3.35). After 10 days, basal lipid oxidation increased, while CHO oxidation decreased (both P<0.01) in groups II and III and was unchanged in group I. Disclosure A.Merovci: None. B.Finley: None. A.Chavez: None. A.A.Hansis-diarte: None. S.Neppala: None. D.Tripathy: None. R.A.Defronzo: Advisory Panel; AstraZeneca, Bayer Inc., Boehringer-Ingelheim, Novo Nordisk, Research Support; AstraZeneca, Boehringer-Ingelheim, Merck & Co., Inc., Speaker's Bureau; AstraZeneca.

Sodium-glucose transporter 2 (SGLT2) inhibitors are associated with increased risk of euglycemic diabetic ketoacidosis in T2DM. Possible mechanisms include increased lipolysis, elevated glucagon, and decreased plasma insulin levels. Therefore, concomitant high dose insulin as well as thiazolidinediones could potentially attenuate the rise in β-OHB because of anti-lipolytic effects. However, this has not been examined in the real-world clinical studies. We examined the effect of long-term Empagliflozin therapy on plasma β-OHB in veterans with T2DM. A retrospective chart review was performed in 43 subjects who had fasting β-OHB, C-peptide and detailed anthropometric measurements and were followed for 23 ± 2.5 months. Subjects were categorized into two groups based on fasting β-OHB concentrations (< or ≥2.8mg/dl). Eleven patients (24.4%) had high (6.03 ±1.22mg/dl) while 32 (74.6%) had normal β-OHB (1.42±0.09 mg/dL). There was no difference in age (59 ± 4 vs 62 ±2 yrs), BMI (35±1 vs 32 ±1 kg/m2), or the duration of diabetes (15 ± 3 vs 18±2 yrs) between the two groups. Subjects with higher β-OHB had higher HbA1c (8.9 ±0.7 vs 7.9 ± 0.3%, p<0.05). There was no difference in fasting C-peptide (3.2 ± 0.9 vs 3.5 ± 0.5ng/ml), total daily insulin dose (184± 43 vs 214±19 units/day), number of subjects on Pioglitazone (54 vs 35%) or GLP-1 agonist therapy (36 vs 52%) between the two groups. In conclusion, long-term therapy with Empagliflozin leads to elevated β-OHB in 25% of T2DM and it was associated with poor glycemic control. Concomitant insulin or pioglitazone therapy did not alter plasma β-OHB concentration. Disclosure L.C.Ortiz: None. J.Wortham: None. S.Pinkson: None. J.Trejo: None. A.S.Mendoza: None. X.Chen: None. D.Tripathy: None.

Objective: Prandial hyperinsulinemia after Roux-en-Y gastric bypass surgery (GB), and to lesser degree after sleeve gastrectomy (SG), has been attributed to rapid glucose flux from the gut and increased insulinotropic gut hormones. However, beta-cell sensitivity to exogenous incretin is reduced after GB. This study examines the effect of GB versus SG on prandial glycemia and beta-cell response to increasing concentrations of endogenous incretins.Methods: Glucose kinetics, insulin secretion rate (ISR), and incretin responses to 50-g oral glucose ingestion were compared between ten nondiabetic participants with GB versus nine matched individuals with SG and seven nonoperated normal glucose tolerant control individuals (CN) with and without administration of 200 mg of sitagliptin.Results: Fasting glucose and hormonal levels were similar among three groups. Increasing plasma concentrations of endogenous incretins by two- to three-fold diminished prandial glycemia and increased beta-cell secretion in all three groups (p < 0.05), but insulin secretion per insulin sensitivity (i.e., disposition index) was increased only in GB (p < 0.05 for interaction). However, plot of the slope of ISR (from premeal to peak values) versus plasma glucagon-like peptide-1 concentration was smaller after GB compared with SG and CN.Conclusions: After GB, increasing incretin activity augments prandial beta-cell response whereas the beta-cell sensitivity to increasing plasma concentrations of endogenous incretin is diminished. imageConclusions: After GB, increasing incretin activity augments prandial beta-cell response whereas the beta-cell sensitivity to increasing plasma concentrations of endogenous incretin is diminished. image

Roux-en-Y gastric bypass surgery (GB) and sleeve gastrectomy (SG) increase prandial insulin and glucagon secretion but reduce the endogenous glucose production (EGP) response to hypoglycemia compared to non-operated controls (CN), suggesting that parasympathetic nervous system (PNS) plays a role. Here, we investigated the effect of acute PNS blockade on the post-meal counterregulatory response to insulin-induced hypoglycemia in GB and SG compared to CN. Glucose kinetics and islet-cell secretion were measured in 9 non-diabetic subjects with GB, 7 with SG, and 5 CN during hyperinsulinemic hypoglycemic clamp (~3.2mM) combined with meal ingestion on two separate days with and without intravenous atropine infusion. Glucose and hormonal levels were similar at baseline and during steady state hypoglycemia before meal ingestion in 3 groups and unaffected by atropine. Atropine infusion diminished prandial systemic appearance of ingested glucose (RaO) by 30%, EGP by 40%, and glucagon response to hypoglycemia by 90%, in controls. In GB or SG, blocking PNS had no effect on the RaO or meal-induced hyperglucagonemia, but increased EGP in SG without any effect in GB (p<0.05 interaction). These findings indicate that cholinergic signal contributes to the recovery from hypoglycemia by meal consumption in humans. However, bariatric surgery dissipates PNS-mediated physiologic responses to hypoglycemia in the fed state.

ABSTRACT Background/Aims: Prandial hyperinsulinemia after Roux-en Y gastric bypass surgery (GB), and to lesser degree after sleeve gastrectomy (SG), has been attributed to rapid glucose flux from the gut and increased insulinotropic gut hormones. However, {beta}-cell sensitivity to exogenous incretin is markedly reduced after GB. This study examines the effect of GB versus SG on prandial glycemia and {beta}-cell response to increasing concentrations of endogenous incretins. Methods: Glucose kinetics, insulin secretion rate (ISR), and incretin responses to 50-gram oral glucose ingestion were compared between 10 non-diabetic subjects with GB versus 9 matched individuals with SG and 7 non-operated normal glucose tolerant controls (CN) on two days with and without administration of 200 mg sitagliptin. Results: Fasting glucose and hormonal levels were similar among 3 groups. Increasing plasma concentrations of endogenous incretins by 2-3-fold diminished post-OGTT glycemia and increased {beta}-cell secretion in all 3 groups (p<0.05), but insulin secretion per insulin sensitivity (i.e., disposition index) was increased only in GB (p<0.05 for interaction). As a result, sitagliptin administration led to hypoglycemia in 3 of 10 GB. Yet, plot of the slope of ISR versus the increase in endogenous incretin concentration was smaller after GB compared to both SG and CN. Conclusion: Augmented glycemic-induced {beta}-cell response caused by enhanced incretin activity is unique to GB and not shared with SG. However, the {beta}-cell sensitivity to increasing concentrations of endogenous incretin is smaller after bariatric surgery, particularly after GB, compared to non-operated controls, indicating a long-term adaptation of gut-pancreas axis after these procedures.

Improved renal oxygenation is proposed as a potential reno-protective mechanism of SGLT2 inhibitors in T2DM. Bold-MRI studies in nondiabetic subjects showed no effect with dapagliflozin and improved renal cortical oxygenation with empagliflozin in T1DM. No studies have examined renal oxygenation in T2DM. We examined the effect of dapagliflozin (10 mg) on renal oxygen delivery and oxygen consumption in 7 T2DM (age=58±3 yrs, BMI = 30±1.8 kg/m2) and 7 NGT (age = 47±3.4 yrs, BMI = 28.6±1.6kg/m2) subjects who received a single dose of dapagliflozin or placebo. Renal vein (SvO2) and radial artery (SaO2) hemoglobin saturation were measured with i-STAT point of care analyzer and renal blood flow with PAH infusion before and 4 hours after dapagliflozin/placebo. At baseline arterial (CaO2, 19 ± 0.8 vs 19 ± 0.7 ml/dl, p=NS) and renal venous (CvO2, 16 ± 0.9 vs 18 ± 0.7 ml/dl, p=NS) oxygen Content were similar in DAPA and PLAC. Thus, there was no difference in renal oxygen delivery (478 ± 29 vs 533 ±27 ml/min/m2) between DAPA and PLAC groups. Following DAPA/PLAC renal plasma flow did not change, and there was no change in arterial (CaO2) (19 ± 0.8 vs 18.2 ± 0.7 ml/dl, p=NS) or renal venous (CvO2) (16 ± 0.9 vs 15.5 ± 0.9 ml/dl) oxygen content in DAPA or PLAC groups. Renal oxygen consumption following DAPA (67 ± 10 vs 78 ±13 ml/min/m2, p=NS) and PLAC (42 ± 8 vs 50 ± 6 ml/min/m2, p=NS) groups were not different versus baseline. Conclusion: A single acute dose of dapagliflozin does not alter renal oxygen delivery or consumption in T2DM or NGT subjects. Disclosure D. Tripathy: None. X. Chen: None. R. Chilton: None. A.A. Hansis-Diarte: None. M. Salehi: None. C. Solis-Herrera: None. E. Cersosimo: None. R.A. DeFronzo: Speaker's Bureau; AstraZeneca. Advisory Panel; AstraZeneca, Bayer Inc., Boehringer-Ingelheim, Novo Nordisk. Research Support; AstraZeneca, Boehringer-Ingelheim, Merck & Co., Inc. Funding AstraZeneca

Abstract Disclosure: G. Le: None. S. Pinkson: None. J. Trejo: None. L. Gondin Hernandez: None. M. Mok: None. A. endoza: None. D. Tripathy: None. There is controversy regarding the effects of long-term GnRH agonist therapy on cardiovascular risk factors in older men with prostate cancer. GnRH agonists are used for gender affirming hormone therapy in adolescents and in adults who fail to suppress testosterone adequately. We examined the cardiometabolic effects of long-term GnRH agonist therapy in transwomen veterans. A retrospective chart review was performed on 74 transwomen veterans who were followed at the ALM VA Endocrinology clinic for at least 12 months and had detailed clinical, hormonal and biochemical profile (testosterone, estradiol, HbA1c, lipid profile) measured. Thirtytwo transwomen on GnRH agonist therapy (age 48 ± 2 yrs, BMI 28 ± 1 kg.m2) followed for 45 ± 5 months were compared with 22 transwomen (age 44 ± 3 yrs, BMI 28 ± 2 kg.m2) followed for 41 ± 7 months not on GnRH therapy. In the GnRH group, 14 were on oral E2, 12 on E2 patch and 6 were on E2 Injection. Similarly, in the non-GnRH group, the number of subjects on oral E2, E2 patch or E2 Injection were 17, 1, and 4 respectively. The average oral estrogen dose in both groups was 4 ± 0.4 mg. In the GnRH group, serum testosterone declined from 420 ± 36 ng/dl to 40 ± 5 ng/dL and serum estradiol before and after therapy was 39 ± 9 vs 89 ± 12 pg/mL. GnRH therapy led to increase in BMI (28 ± 1 vs 31 ± 2 kg.m2, p=0.006), though no difference was observed in SBP (126 ± 2 vs 120 ± 2 mmHg, p=ns), total Cholesterol (170 ± 7 vs 171 ± 8 mg/dL), HDL Cholesterol (45 ± 2 vs. 46 ± 2 mg/dL), LDL Cholesterol (98 ± 7 vs 99 ± 5 mg/dL) before and after treatment. There was no change in BMI (28 ± 2 vs 29 ± 1 kg.m2), SBP (121 ± 3 vs 125 ± 3, p=ns), total cholesterol (173 ± 5 vs. 170 ± 9 mg/dL), HDL chol (46 ± 2 vs. 49 ± 2 mg/dL), or LDL chol (97 ± 6 vs. 95 ± 7 mg/dL) in the control group. Plasma triglycerides increased in both the GnRH (134 ± 10 vs 168 ± 16 mg/dL, p<0.05) as well as in the control group (154 ± 30 vs 167 ± 20 mg/dL, p<0.05) after treatment. In conclusion, long-term estrogen therapy in transwomen increased plasma triglyceride. Concomitant GnRH agonist therapy was associated with greater weight gain, but did not affect other cardiovascular risk factors. Presentation: Saturday, June 17, 2023

In the pathogenesis of type 2 diabetes mellitus (T2DM), diet plays a key role. Individualized medical nutritional therapy, as part of lifestyle optimization, is one of the cornerstones for the management of T2DM and has been shown to improve metabolic outcomes. This paper discusses major aspects of the nutritional intervention (including macro- and micronutrients, nutraceuticals, and supplements), with key practical advice. Various eating patterns, such as the Mediterranean-style, low-carbohydrate, vegetarian or plant-based diets, as well as healthy eating plans with caloric deficits have been proven to have beneficial effects for patients with T2DM. So far, the evidence does not support a specific macronutrient distribution and meal plans should be individualized. Reducing the overall carbohydrate intake and replacing high glycemic index (GI) foods with low GI foods have been shown as valid options for patients with T2DM to improve glycemic control. Additionally, evidence supports the current recommendation to reduce the intake of free sugars to less than 10% of total energy intake, since their excessive intake promotes weight gain. The quality of fats seems to be rather important and the substitution of saturated and trans fatty acids with foods rich in monounsaturated and polyunsaturated fats lowers cardiovascular risk and improves glucose metabolism. There is no benefit of supplementation with antioxidants, such as carotene, vitamins E and C, or other micronutrients, due to the lack of consistent evidence showing efficacy and long-term safety. Some studies suggest possible beneficial metabolic effects of nutraceuticals in patients with T2DM, but more evidence about their efficacy and safety is still needed.

Abstract Disclosure: S. Pinkson: None. J. Trejo: None. A. Mendoza: None. L. Gondin Hernandez: None. S. Chen: None. S. ahuja: None. D. Tripathy: None. Over the past 15 years, transgender veterans seeking Gender Affirming Hormone Therapy (GAHT) have increased significantly. The metabolic effects of long-term GAHT have been controversial possibly because of multiple confounding factors and different methodologies. We examined long-term effects of estradiol and testosterone on insulin sensitivity and insulin secretion in nondiabetic transwomen and transmen. A total of 4 groups (i) 7 transwomen (age 50 ± 4 yr, BMI 31 ± 2 kg/m2) (ii) 6 transmen (age 38 ± 4yr, BMI 33 ± 2 mg/m2) followed for 52 ± 9 months and as a control group (iii) six cisgender men (age 36 ± 4 yrs, BMI 32 ± 2 kg/m2) and (iv) 8 cisgender women (age 39 ± 4 yr, BMI 28 ± 2 kg/m2) participated in an OGTT and Botnia clamp (IV glucose tolerance test: IVGTT followed by hyperinsulinemic (80 mU.m2/min euglycemic clamp). Total testosterone (by equilibration dialysis method), estradiol, sex hormone binding globulin (SHBG) and lipid profile was measured in all subjects. Insulin, and C-peptide were measured every 30 min during the OGTT. Insulin sensitivity was measured as the M-value form last 30 minutes of insulin clamp and as Matsuda index of insulin sensitivity from the OGTT. Indices of insulin secretion (data pending) was calculated as the first phase insulin response from IVGTT (FPIR: 2-10min) and as indices of beta cell function from OGTT: Insulin secretion/insulin resistance index (Insulin 0-120/Glucose 0-120 X Matsuda index). Plasma estradiol in transwomen was 209 ± 92 pg/ml vs. 32 ± 6 pg/ml in cisgender men. Similarly, the total testosterone level in transmen was 319 ± 57 vs. 19 ± 4 ng/dl in cisgender women. There was no difference in SHBG levels between the groups. The body fat content was not different between trans or cis men (36 ± 3 vs 35 ± 1.4 % ) while it was higher in trans vs cis women (40 ± 0.8 vs 30 ± 3%). There was no difference in HbA1c (5.4 ± 0.2 vs 5.2 ± 0.2%, p=ns) between transwomen and cismen and (5.6 ± 0.1 vs 5.5 ± 0.1, p=ns) transmen and ciswomen. The glucose AUC was higher in transmen vs cisgender women (5,487 ± 994 vs. 3,420 ± 533; P < 0.05). There was no difference in glucose AUC between the transwomen and cismen. There was no difference in insulin sensitivity (M-value) between transwomen and cisgender men (6.9 ± 1.2 vs 7.0 ± 1.4 mg.kg/min, p=ns), while it tended to be worse in transmen compared to cisgender women ( 6.03 ± 1.0 vs 7.7± 0.6 mg.kg/min, p=0.1). In both groups M-Value was inversely related to BMI (r=-0.59; p<0.05). There was no relationship between insulin sensitivity and plasma total testosterone level. HDL cholesterol was lower in transmen (41 ± 2.5 vs 55 ± 4 mg/dL, p<0.05) versus cisgender women though there was no difference in triglyceride, total or LDL cholesterol between the groups. In conclusion long-term GAHT therapy does not adversely affect insulin sensitivity in trans men or women and the mildly altered glucose tolerance is likely a result of higher BMI in transmen. Presentation: Sunday, June 18, 2023

Asbtract Context Sustained increases in plasma glucose promote skeletal muscle insulin resistance independent from obesity and dyslipidemia (ie, glucotoxicity). Skeletal muscle lipids are key molecular determinants of insulin action, yet their involvement in the development of glucotoxicity is unclear. Objective To explore the impact of mild physiologic hyperglycemia on skeletal muscle lipids. Design Single group pretest-posttest. Participants Healthy males and females with normal glucose tolerance. Interventions 72-hour glucose infusion raising plasma glucose by ~50 mg/dL. Main Outcome Measures Skeletal muscle lipids, insulin sensitivity, lipid oxidation. Results Despite impairing insulin-mediated glucose disposal and suppressing fasting lipid oxidation, hyperglycemia did not alter either the content or composition of skeletal muscle triglycerides, diacylglycerides, or phospholipids. Skeletal muscle ceramides decreased after glucose infusion, likely in response to a reduction in free fatty acid concentrations. Conclusions Our results demonstrate that the major lipid pools in skeletal muscle are unperturbed by sustained increases in glucose availability and suggest that glucotoxicity and lipotoxicity drive insulin resistance through distinct mechanistic pathways.

Although the effect of glucagon on glucose metabolism has been well characterized, its effect on lipid metabolism, particularly lipolysis and de novo lipogenesis, in humans in vivo has been poorly studied with controversial results. We examined the effect of short-term hyperglucagonemia on de novo lipogenesis (DNL) and endogenous glucose production (EGP) in 8 healthy normal glucose tolerant subjects (5M/3F, age=35±5, BMI= 24±1) who received a 12-hour (6PM to 6AM) glucagon infusion (6ng/kg/min) infusion with measurement of EGP (3-3H-glucose) on the following morning 6-AM. Subjects received deuterated water (D2O, 5g/kg fat free mass) at PM on the night prior to study. 8 weeks later subjects returned for a repeat study with 12-hour infusion of normal saline. DNL was quantified by measuring the incorporation of deuterated water into circulating triglycerides. Gluconeogenic rate was measured as (EGP) x (plasma C5/C2 glucose ratio) (EGP) x (plasma C5/C2 glucose ratio) . Plasma esterified and non-esterified FFA levels were measured with gas chromatography mass spectrometry (GC-MS) . Plasma glucagon increased from 57±3 to 219±21 pg/ml within one hour and remained elevated throughout the study. DNL was significantly decreased (1.64 ± 0.58% vs. 3.± 0.98%, p<0.05) after glucagon versus saline infusion. Both plasma palmitate (0.73 ± 0.vs. 0.67 ± 0.mmol/L) and total FFA (1.35 ± 0.vs. 1.21 ±0.mmol/L) concentrations were elevated after glucagon infusion (p<0.05) . EGP increased following glucagon infusion (2.13 ± 0.14 vs. 1.97± 0.11mg/kg/min, p =0.006) . The increase in EGP was primarily due to increased gluconeogenesis (1.48 ± 0.14 vs. 1.27 ± 0.11, p=0.02) , while the rate of glycogenolysis did not change (0.65± 0.14 vs. 0.70± 0.11, p=ns) . Conclusion: Short-term (12-hour) physiologic hyperglucagonemia in healthy subjects reduces hepatic de novo lipogenesis, stimulates adipose tissue lipolysis, and increases hepatic glucose production by increasing gluconeogenesis. Disclosure X.Chen: None. F.Carli: None. S.Pezzica: None. G.Mocciaro: None. D.Ciociaro: None. A.Gastaldelli: Advisory Panel; Boehringer Ingelheim International GmbH, Novo Nordisk Global Business Services, Consultant; Boehringer Ingelheim International GmbH, Inventiva Pharma, Other Relationship; Eli Lilly and Company, Gilead Sciences, Inc., Pfizer Inc., Speaker's Bureau; Novo Nordisk. R.A.Defronzo: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Intarcia Therapeutics, Inc., Novo Nordisk, Research Support; AstraZeneca, Boehringer Ingelheim International GmbH, Merck & Co., Inc., Speaker's Bureau; AstraZeneca. D.Tripathy: None. Funding EFSD Albert Renold Travel Fellowship; FAVHR

The insulin-sensitizer pioglitazone exerts its cardiometabolic benefits in type 2 diabetes (T2D) through a redistribution of body fat, from ectopic and visceral areas to subcutaneous adipose depots. Whereas excessive weight gain and lipid storage in obesity promotes insulin resistance and chronic inflammation, the expansion of subcutaneous adipose by pioglitazone is associated with a reversal of these immunometabolic deficits. The precise events driving this beneficial remodeling of adipose tissue with pioglitazone remain unclear, and whether insulin-sensitizers alter the lipidomic composition of human adipose has not previously been investigated. Using shotgun lipidomics, we explored the molecular lipid responses in subcutaneous adipose tissue following 6months of pioglitazone treatment (45mg/day) in obese humans with T2D. Despite an expected increase in body weight following pioglitazone treatment, no robust effects were observed on the composition of storage lipids (i.e., triglycerides) or the content of lipotoxic lipid species (e.g., ceramides and diacylglycerides) in adipose tissue. Instead, pioglitazone caused a selective remodeling of the glycerophospholipid pool, characterized by a decrease in lipids enriched for arachidonic acid, such as plasmanylethanolamines and phosphatidylinositols. This contributed to a greater overall saturation and shortened chain length of fatty acyl groups within cell membrane lipids, changes that are consistent with the purported induction of adipogenesis by pioglitazone. The mechanism through which pioglitazone lowered adipose tissue arachidonic acid, a major modulator of inflammatory pathways, did not involve alterations in phospholipase gene expression but was associated with a reduction in its precursor linoleic acid, an effect that was also observed in skeletal muscle samples from the same subjects. These findings offer important insights into the biological mechanisms through which pioglitazone protects the immunometabolic health of adipocytes in the face of increased lipid storage.

Insulin is an essential hormone that regulates glucose homeostasis and metabolism. Insulin resistance (IR) arises when tissues fail to respond to insulin, and it leads to serious health problems including Type 2 Diabetes (T2D). Obesity is a major contributor to the development of IR and T2D. We previously showed that gene expression of alcohol dehydrogenase 1B (ADH1B) was inversely correlated with obesity and IR in subcutaneous adipose tissue of Mexican Americans. In the current study, a meta-analysis of the relationship between ADH1B expression and BMI in Mexican Americans, African Americans, Europeans, and Pima Indians verified that BMI was increased with decreased ADH1B expression. Using established human subcutaneous pre-adipocyte cell lines derived from lean (BMI < 30 kg m−2) or obese (BMI ≥ 30 kg m−2) donors, we found that ADH1B protein expression increased substantially during differentiation, and overexpression of ADH1B inhibited fatty acid binding protein expression. Mature adipocytes from lean donors expressed ADH1B at higher levels than obese donors. Insulin further induced ADH1B protein expression as well as enzyme activity. Knockdown of ADH1B expression decreased insulin-stimulated glucose uptake. Our findings suggest that ADH1B is involved in the proper development and metabolic activity of adipose tissues and this function is suppressed by obesity.

Although the effect of glucagon on glucose metabolism has been well characterized, its effect on adipose tissue and lipid metabolism in humans in vivo has been poorly studied with controversial results. We examined the effect of short-term hyperglucagonemia on adipocyte metabolism in 8 healthy normal glucose tolerant subjects (5M/3F, age=35±5, BMI = 24±1) who received a 12-hour (6PM to 6AM) glucagon infusion (6ng/kg/min) with 14C-glycerol infusion; subcutaneous abdominal adipose tissue biopsy was obtained at 6AM. 8 weeks later subjects returned for a repeat study with 12-hour infusion of normal saline. Plasma glucagon increased from 57±3 to 219±21 pg/ml within one hour and remained elevated throughout the study. Glycerol turnover rate (5.1±0.6 vs. 3.8±0.6 µmol/kg•min, p<0.05) increased by 34%, and the adipose tissue insulin resistance index (fasting plasma FFA x Insulin) more than doubled (5.8±0.8 vs. 2.8±0.7 mM•mU/L, p<0.05) after 12-hour glucagon infusion compared to saline. mRNA expression of genes involved in lipolysis in adipose tissue were upregulated after glucagon infusion (ATGL, 1.14±0.07 vs. 0.77±0.03; HSL, 1.17±0.03 vs. 0.9±0.13; MGL, 1.2±0.04 vs. 0.82±0.2, all p<0.05). Plasma concentration of proinflammatory markers (IL-1β, 0.65±0.05 vs. 0.49±0.05 pg/mL; TNF-α, 2.03±0.23 vs. 1.75±0.17 pg/mL, both p<0.05) and lipidomes involved in inflammatory pathways (lysophosphatidylcholine, 126±11 vs. 51±7 nmol/ml, p<0.005; phosphatidylcholine, 385±24 vs. 306±25 nmol/ml, p<0.01; ceramide, 1.7±0.2 vs. 1.2±0.2 nmol/ml, p<0.01) also increased after 12-hour glucagon infusion. H&E and CD68 immunofluorescence staining in adipose tissue displayed the crown-like structures (CLS) and increased infiltration of macrophages following glucagon infusion. Conclusion: Short-term (12-hour) physiologic hyperglucagonemia stimulates adipose tissue lipolysis, induces adipocyte insulin resistance, and promotes adipose tissue and systemic inflammation. Disclosure X. Chen: None. M. Fourcaudot: None. L. Norton: None. R. A. Defronzo: Other Relationship; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Intarcia Therapeutics, Inc., Janssen Pharmaceuticals, Inc., Novo Nordisk, Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Speaker’s Bureau; Self; AstraZeneca, Novo Nordisk. D. Tripathy: None. Funding Foundation for Advancing Veterans’ Health Research