To examine possible feedback inhibition of insulin on proinsulin secretion, we measured serum proinsulin levels before and after 120 min of euglycemic hyperinsulinemia (90-100 mU/liter) in 11 normal and 7 obese hyperinsulinemic subjects and 6 patients with beta-cell adenoma (n = 4), carcinoma, or hyperplasia. Baseline proinsulin levels accounted for 19%, 14%, and 56% of the total immunoreactive insulin in the 3 groups, respectively. Compared to normal subjects, baseline proinsulin levels were elevated (P less than 0.02) by 4- and 6-fold in obese subjects and patients with autonomous insulin secretion, respectively, but there was an overlap between the groups. In both normal and obese subjects, hyperinsulinemia suppressed proinsulin secretion by 45-50% (P less than 0.02), whereas no response occurred in the patients. Thus, the 120 min values were clearly different in the patients and the normal or obese subjects. After removal of the adenoma in 4 patients, baseline proinsulin levels and the response to hyperinsulinemia were normalized, but they remained elevated after a partial pancreatectomy or tumor removal in the patients with beta-cell hyperplasia or carcinoma. Thus, proinsulin secretion is under negative feedback control of insulin in both normal man and hyperinsulinemic obese subjects. In patients with insulinoma or beta-cell hyperplasia, this control is lost.

AIMS:To compare the efficacy and safety of insulin lispro protamine suspension (ILPS) versus insulin glargine once daily in a basal-bolus regimen in type 2 diabetes mellitus (T2DM) patients.METHODS:Three hundred eighty-three insulin-treated patients were randomized to either ILPS plus lispro or glargine plus lispro in this open-label 24-week European study. Insulin doses were titrated to predefined blood glucose (BG) targets. Non-inferiority of ILPS versus glargine was assessed by comparing the upper limit of the 95% confidence interval (CI) for the change of HbA1c from baseline to week 24 (adjusted for country and baseline HbA1c) with the non-inferiority margin of 0.4%. Secondary endpoints included HbA1c categories, BG profiles, insulin doses, hypoglycaemic episodes, adverse events and vital signs.RESULTS:Non-inferiority of ILPS versus glargine in the change of HbA1c from baseline was shown: least-square mean between-treatment difference (95% CI) was 0.1% (-0.11; 0.31). Mean changes at week 24 were -1.05% (ILPS) and -1.20% (glargine). HbA1c <7.0% was achieved by 21.7 versus 29.4% of patients. Mean basal/mealtime insulin doses at week 24 were 29.6/36.2 IU/day (ILPS) versus 32.8/42.2 IU/day (glargine); the difference was not statistically significant for total dose (p = 0.7). In both groups, 56.1/25.7% versus 63.6/19.3% of patients experienced any/nocturnal hypoglycaemia (p = 0.2 for both). No relevant differences were noted in any other variables.CONCLUSIONS:A basal-bolus regimen with ILPS once daily resulted in non-inferior glycaemic control compared to a similar regimen with glargine, without statistically significant or clinically relevant differences in hypoglycaemia. ILPS-based regimens can be considered an alternative to basal-bolus regimens with glargine for T2DM patients.

Aims/hypothesis: We previously reported that treatment of acne with 13-cis-retinoic acid causes insulin resistance and disturbances in lipid metabolism resembling those of the insulin-resistance syndrome. It is not known whether this is associated with alterations in the concentrations of serum adiponectin, an insulin-sensitising hormone secreted by adipocytes. Materials and methods: Eleven men ( age 24 +/- 2 years, BMI 22.1 +/- 0.9 kg/m(2)) received 13-cis- retinoic acid (Roaccutan) treatment for acne for an average of 5 months. The insulin sensitivity of the subjects and concentrations of serum adiponectin were measured before, during and 1 month after the treatment by a euglycaemic-hyperinsulinaemic clamp and ELISA, respectively. Results: There was a reversible reduction in whole-body insulin sensitivity during therapy with 13-cis-retinoic acid. This was associated with a transient 34% increase in serum adiponectin concentration ( from 5.3 +/- 0.9 to 7.1 +/- 1.2 mu g/ml, p< 0.05), with a return to pretreatment levels by 1 month after the end of therapy. In the pretreatment study, as well as in the study performed 1 month after the end of therapy, there was a small yet significant decrease in serum adiponectin concentration during a 4-h euglycaemic hyperinsulinaemic clamp. This decrease was not observed in the clamp performed during treatment with 13-cisretinoic acid. Conclusions/interpretation: There is a paradoxical increase in fasting serum adiponectin concentration during the 13-cis-retinoic acid-induced reduction in insulin sensitivity.

Type 2 diabetes is characterized by increased acute phase serum proteins. We wanted to study how these proteins are related to complement activation in type 2 diabetes and how improvement of glycemic control affects them or complement activation. A total of 29 type 2 diabetic patients (age, 55.2 ± 1.8 years, glycosylated hemoglobin [HbA1c] 8.9% ± 0.2%, body mass index [BMI] 30.9 ± 0.8 kg/m2, duration 5.9 ± 1.3 years) participated in the study. They were previously treated either with diet alone or in combination with 1 oral antihyperglycemic medication. After a period of at least 4 weeks run-in on diet only, the patients were randomized to pioglitazone, glibenclamide, or placebo. Blood samples were taken before the treatments and at the end of the 6-month therapy. Basal C-reactive protein (CRP) level was related to acylation-stimulating protein (ASP) concentration (r = .55, P < .01), and many acute phase serum protein concentrations were associated with each other. The treatment reduced HbA1c level in the pioglitazone (from 9.1 ± 0.3% to 8.0 ± 0.5%, P < .05) and glibenclamide (from 8.9 % ± 0.3% to 7.7% ± 0.2%, P < .05) groups. Glibenclamide treatment was associated with a reduction in α-1-antitrypsin (P < .05), ceruloplasmin (P < .01), and complement C3 protein (C3) (P < .05). Although ASP did not change significantly in any of the treatment subgroups, in the whole patient population, the change in HbA1c during the treatments correlated positively with the change in ASP, (r = .43, P < .05). The changes in many acute phase serum proteins and ASP were related to each other. In conclusion, (1) inflammatory factors and complement activation are associated in patients with type 2 diabetes, and (2) changes in hyperglycemia are related to changes in the concentration of the complement activation product, ASP.

AIM To evaluate the effect of maternal diabetes on the concentrations of free and bound leptin at birth and during postnatal adaptation. METHODS Total, bound, and free leptin concentrations and the percentage of free leptin were measured in cord plasma and plasma at 3 days of age of 13 term infants of mothers with gestational diabetes mellitus (GDM) and 13 term infants of healthy mothers. Gestational age was 40.2 (1.4) weeks, and birth weight was 3693 (549) g (means (SD)). RESULTS At birth, infants of mothers with GDM had significantly higher concentrations of total, bound, and free leptin and a higher percentage of free leptin (all p < 0.05). In all infants, these concentrations were significantly lower at 3 days of age than at birth (all p < 0.003), and the differences in concentrations of total, bound, and free leptin between the two groups were no longer significant. In infants of mothers with GDM, the percentage of free leptin remained unchanged, and was higher (p<0.05) than in infants of healthy mothers; in the latter group the percentage of free leptin significantly declined (p = 0.02). CONCLUSIONS GDM appears to influence fetoplacental leptin metabolism. This effect may be mediated through altered maternal glucose metabolism, or insulinaemia, or both.

SUMMARY Aim We investigated the effect of carbohydrate availability and euglycaemic hyperinsulinaemia on intramuscular and plasma amino acids in 14 healthy men (age 26.5 ± 0.9 years, b.m.i. 22.9 ± 0.5 kg/m2).Methods Insulin was infused (1.5 mU/kg/min) for 240 min both after a carbohydrate depleting exercise and after carbohydrate loading. Muscle samples were taken before and after hyperinsulinaemia. Plasma and intramuscular amino acid concentrations were measured.Results Insulin‐mediated glucose disposal was similar after carbohydrate depletion (65.2 ± 1.9 μmol/kg/min) and loading (66.9 ± 2.8 μmol/kg/min). Carbohydrate depletion was associated with decreased alanine and increased branched chain amino acid (BCAA) concentrations in muscle and plasma. Blood lactate was lower after carbohydrate depletion (477 ± 25 μmol/l) than loading (850 ± 76 μmol/l, p < 0.001). In carbohydrate depletion, hyperinsulinaemia resulted in a greater increase in intramuscular (from 927 ± 48 nmol/g muscle to 2029 ± 104 nmol/g muscle, p < 0.001), than plasma (from 197 ± 6.7 μmol/l to 267 ± 11 μmol/l, p < 0.001) alanine. After carbohydrate loading muscle alanine did not rise significantly (from 1546 ± 112 nmol/g muscle to 1781 ± 71 nmol/g muscle) whereas plasma alanine decreased (from 339 ± 26 μmol/l to 272 ± 13 μmol/l, p < 0.05).Conclusions (1) Carbohydrate availability has profound effects on the interrelationship between glucose and amino acid metabolism and on the form of storage for glucose‐derived carbons. (2) For most amino acids changes in plasma levels of amino acids are not related to changes in concentrations of intramuscular amino acids during hyperinsulinaemia.

Aim-To study the effect of maternal preeclampsia on cord plasma leptin concentrations in preterm infants.Methods-Leptin concentration was analysed in cord plasma of 74 preterm infants, gestational age 24 to 32 weeks. Of these, 14 were born to pre-eclamptic mothers, in 10 intrauterine growth retardation (IUGR) was present, and 59 had been exposed antenatally to corticosteroids.Results-The mean (SD) concentration of cord plasma leptin was 1.31 (0.88) mu g/l. A significant correlation was found between leptin concentration and gestational age (r = 0.336; p = 0.0037). Leptin levels were higher in infants of pre-eclamptic mothers (p = 0.0007), in those with IUGR (p = 0.0005), and in infants exposed antenatally to corticosteroids (p = 0.02). In multiple regression analysis, leptin was associated with gestational age and maternal pre-eclampsia (both p < 0.05), but not with antenatal corticosteroids.Conclusions-Increased fetal leptin in maternal pre-eclampsia may reflect a physiological adaptation to fetal stress such as hypoxia.

Objectives: Because estrogens stimulate the synthesis and release of leptin in the adipocytes, the effect of antiestrogens on the circulating leptin levels were studied. Methods: Thirty postmenopausal patients with breast cancer were randomized to start either with tamoxifen (20 mg/day, n=15) or toremifene (40 mg/day, n=15), and the patients were examined and serum leptin concentrations measured before the study and at 6 and 12 months. Results: The baseline leptin concentrations ranged from 4.4 to 60.0 μg/l (15.3±13.1 μg/l, mean±S.D.), and it correlated positively with the body mass index (BMI) of the subjects (r=0.73, P=0.0001). Taking as a whole the antiestrogen regimen was associated with elevated leptin levels at 6 months (19.5±13.8 μg/l, P=0.0001) but no excess increase in leptin levels were seen at 12 months (20.9±13.5 μg/l, NS). Subgroup analysis showed no difference between the effects of tamoxifen or toremifene on leptin. BMI increased in 21 women (from 26.2±4.3 to 27.3±4.8 kg/m2, P=0.0001) at 6 months, but not after that; in nine women BMI did not change. There was no significant correlation between the change in leptin levels and the change in BMI in either group implying that antiestrogens may specifically stimulate leptin production. Conclusions: Antiestrogens may stimulate the synthesis and release of leptin in the adipocytes. This effect of antiestrogens resembles the effect of estrogen and consequently stimulation of leptin production can be added to the estrogenic effects of antiestrogens.

Fatty acid transporter protein (FATP)-1 mRNA expression was investigated in skeletal muscle and in subcutaneous abdominal adipose tissue of 17 healthy lean, 13 nondiabetic obese, and 16 obese type 2 diabetic subjects. In muscle, FATP-1 mRNA levels were higher in lean women than in lean men (2.2 +/- 0.1 vs. 0.6 +/- 0.2 amol/microg total RNA, P < 0.01). FATP-1 mRNA expression was decreased in skeletal muscle in obese women both in nondiabetic and in type 2 diabetic patients (P < 0.02 vs. lean women in both groups), and in all women there was a negative correlation with basal FATP-1 mRNA level and body mass index (r = -0.74, P < 0.02). In men, FATP-1 mRNA was expressed at similar levels in the three groups both in skeletal muscle (0.6 +/- 0.2, 0.6 +/- 0.2, and 0.8 +/- 0.2 amol/microg total RNA in lean, obese, and type 2 diabetic male subjects) and in adipose tissue (0.9 +/- 0.2 amol/microg total RNA in the 3 groups). Insulin infusion (3 h) reduced FATP-1 mRNA levels in muscle in lean women but not in lean men. Insulin did not affect FATP-1 mRNA expression in skeletal muscle in obese nondiabetic or in type 2 diabetic subjects nor in subcutaneous adipose tissue in any of the three groups. These data show a gender-related difference in the expression of the fatty acid transporter FATP-1 in skeletal muscle of lean individuals and suggest that changes in FATP-1 expression may not contribute to a large extent to the alterations in fatty acid uptake in obesity and/or type 2 diabetes.

Hyperleptinemia may be part of the insulin resistance syndrome. We studied serum leptin in preeclampsia, which is an insulin-resistant state, and sought associations between leptin and insulin or insulin sensitivity during and after pregnancy. Twenty-two proteinuric preeclamptic women and 16 normotensive controls were studied during the third trimester. Leptin was higher in preeclampsia (mean +/- SE, 34.6 +/- 3.9 v 20.0 +/- 3.3 microg/L, P = .002) and correlated directly with the level of proteinuria (r = .47, P = .03) and normal pregnancy (r = .52, P = .04), whereas insulin sensitivity as assessed by an intravenous glucose tolerance test showed no relationship to leptin. Leptin was 19.0 +/- 3.6 microg/L in 14 preeclamptic women and 10.1 +/- 2.0 microg/L (P = .11) in 11 controls 3 months after delivery. Leptin correlated directly with insulin both in preeclamptic puerperal women (r = .63, P = .02) and in controls (r = .81, P = .003). Leptin and insulin sensitivity correlated only in preeclamptic puerperal women (r = -.59, P = .02). In conclusion, (1) serum leptin is elevated in preeclampsia, (2) insulin is an important determinant of serum leptin in preeclamptic and normotensive women both during pregnancy and in the puerperium, and (3) hyperleptinemia may be part of the insulin resistance syndrome also in women with prior preeclampsia.

Background An association with subcutaneous adipose tissue TNF alpha expression and insulin resistance has been suggested in obesity/type-2 diabetes, but this has not been examined directly. In the first part of the study we investigated whether this association is present in 7 lean, 10 obese nondiabetic and 9 type-2 diabetic men. In the second part of the study we examined the relationship between adipose tissue TNF alpha mRNA levels and BMI in 81 nondiabetic subjects spanning a wide range of BMIs.Methods Subcutaneous adipose tissue TNF alpha mRNA levels and insulin sensitivity were determined with quantitative RT-competitive PCR and hyperinsulinaemic clamp, respectively.Results Subcutaneous adipose tissue TNF alpha mRNA levels were similar in 7 lean and 10 obese nondiabetic and 9 type-2 diabetic men (P = 0.68), and did not change in response to 240-min hyperinsulinaemia. TNF alpha mRNA levels and insulin sensitivity were not correlated. Unexpectedly, no correlation between TNF alpha mRNA and BMI was found. The relationship between adipose tissue TNF alpha mRNA and BMI was examined further in 31 male and 50 female nondiabetic subjects. The subcutaneous adipose tissue TNF alpha mRNA level correlated with BMI in all subjects (r(S) = 0.32, P < 0.01), and in a subgroup analysis in men (r(S) = 0.55, P < 0.01) but not in women (r(S) = - 0.08). The correlation in men was dependent on a fourfold higher TNF alpha mRNA level in 5 morbidly obese men while there was no difference in TNF alpha mRNA levels in lean or obese men.Conclusions Subcutaneous adipose tissue TNF alpha expression does not correlate with insulin sensitivity in nondiabetic or type-2 diabetic men; is not regulated by acute hyperinsulinaemia; and is increased only in morbidly obese men.

Aims/hypothesis. The purpose of this study was to examine whether fetal leptin concentration correlates with severity of chronic or subchronic fetal hypoxia as indicated by increased fetal concentrations of erythropoietin in fetuses of mothers with Type I (insulin dependent) diabetes mellitus.Methods. We measured leptin and erythropoietin concentrations in cord plasma and amniotic fluid with radioimmunoassay in 25 pregnancies (gestational age 37.2 ± 1.0 weeks). Fetuses with amniotic fluid erythropoietin over 22.5 mU/ml were classified as hypoxic (n = 9) and those with amniotic fluid erythropoietin below 22.5 mU/ml (n = 16) as non-hypoxic.Results. The hypoxic fetuses had significantly higher cord leptin concentrations than non-hypoxic fetuses (median 36.8; range, 12.5–135.1 vs median 16.2; range, 3.7–52.2 μg/l), (p = 0.0066). Cord plasma leptin (n = 25) correlated directly with amniotic fluid erythropoietin (r = 0.727, p = 0.0001), with cord plasma erythropoietin (r = 0.644, p = 0.0005) and with the maternal last trimester HbA1C (r = 0.612, p = 0.0019) and negatively with cord artery pO2 (r = –0.440, p = 0.032), and pH (r = –0.414, p = 0.040).Conclusion/interpretation. Fetal leptin concentrations increased concomitantly with erythropoietin during chronic or subchronic hypoxia. This phenomenon could indicate a role for leptin in fetal adaptation to hypoxia. [Diabetologia (2000) 43: 709–713]

OBJECTIVE: Insulin Mix25 is a new premixed insulin analog containing 25% insulin lispro and 75% neutral protamine lispro (NPL) suspension (NPL insulin). The aim of the study was to compare serum glucose and insulin responses after breakfast in type 2 diabetic patients who received Mix25, premixed regular/NPH (30%/70%), or NPH insulin before the meal. RESEARCH DESIGN AND METHODS: We studied 22 type 2 diabetic patients of age 62 +/- 1 years, BMI 30 +/- 1 kg/m2, duration of diabetes 15 +/- 2 years, duration of insulin therapy 6 +/- 1 years, insulin dose 65 +/- 6 U/day, and HbA1c 7.9 +/- 0.2%. Ten healthy individuals (age 56 +/- 1 years, BMI 28 +/- 1 kg/m2) served as control subjects. Each patient (except healthy subjects, who were studied once each) was studied three times in a double-blind, randomized fashion. After an overnight fast, the patients received 36 +/- 4 U of test insulin. Ten minutes after insulin injection, the patients ingested a breakfast meal (512 kcal, 60% carbohydrate, 20% fat, and 20% protein), identical in all studies. Blood samples were taken before and at 10- to 30-min intervals for 240 min after the breakfast meal. RESULTS: The peak rise in serum glucose was lower after Mix25 (76 +/- 7 mg/dl) than after 30/70 (94 +/- 5 mg/dl, P < 0.05) or NPH (113 +/- 4 mg/dl, P < 0.005) insulin. The incremental area under the serum glucose curve was 36% smaller after Mix25 than after 30/70 (P < 0.01) and 56% smaller than after NPH (P < 0.005) insulin. The peak rise in serum insulin concentration was higher after Mix25 (103 +/- 18 mU/l) than after 30/70 (87 +/- 13 mU/l, P < 0.05) or NPH (62 +/- 12 mU/l, P < 0.01) insulin. The incremental area under the serum insulin curve was higher after Mix25 than after 30/70 during the first 2-3 h (P < 0.02), but the difference disappeared by the end of the 4-h follow-up period. After Mix25 injection, there was an inverse correlation between the glucose response to a meal and insulin dose (r = -0.56, P < 0.01) or the incremental area under the serum insulin curve (r = -0.39, P < 0.05). No such correlations were observed with the other insulins. CONCLUSIONS: Because of its faster initial absorption rate, the new premixed insulin analog Mix25 reduces blood glucose response to a breakfast meal in type 2 diabetic patients compared with premixed 30/70 (regular/NPH) or NPH insulin.

OBJECTIVE To evaluate the quality of diabetes care at a national level in Finland, using level of glycemia as a determinant of success in treatment. RESEARCH DESIGN AND METHODS Physicians and diabetes nurses in 76 randomly selected clinics (59 primary care units and 17 hospitals) evenly covering the whole of Finland were asked to fill in a questionnaire asking for data based on the 1993 medical records of a random sample of 50 diabetic patients from each center (total n = 3,800). HbAlc was used as an index of glycemic control. RESULTS Information on 3,195 (84%) diabetic patients was received. HbAlc was measured in 67% of the patients in 1993. The mean HbAlc in the whole population was 8.6 +/- 1.9% (normal range 4-6%). Some 25% of patients had HbAlc < or = 7.3%, while 25% had HbAlc > or = 9.7%. The mean HbAlc was 8.8 +/- 1.9% in type 1 and 8.5 +/- 1.9% in type 2 diabetic patients. There was no sex difference in the HbAlc level in type 1 diabetic patients. However, male type 2 diabetic patients had better glycemic control than female patients (8.3 +/- 1.9 vs. 8.8 +/- 1.9%, P < 0.0001). The sex difference was independent of the type of therapy. The mean level of glycemic control was lowest among individuals with the shortest duration of diabetes. After 7-9 years after the diagnosis, there was no change in the mean level of glycemia. CONCLUSIONS Average glycemic control is poor in a majority of the diabetic patients in Finland. Better treatment strategies and methods should be used to improve glycemic control and to reduce long-term complications.

1. The role of blood flow as a determinant of skeletal muscle glucose uptake is at present controversial and results of previous studies are confounded by possible direct effects of vasoactive agents on glucose uptake. Since increase in muscle blood flow can be due to increased flow velocity or recruitment of new capillaries, or both, it would be ideal to determine whether the vasoactive agent affects flow distribution or only increases the mean flow. 2. In the present study blood flow, flow distribution and glucose uptake were measured simultaneously in both legs of 10 healthy men (aged 29 +/- 1 years, body mass index 24 +/- 1 kg m-2) using positron emission tomography (PET) combined with [15O]H2O and [18F]fluoro-2-deoxy-D-glucose (FDG). The role of blood flow in muscle glucose uptake was studied by increasing blood flow in one leg with sodium nitroprusside (SNP) and measuring glucose uptake simultaneously in both legs during euglycaemic hyperinsulinaemia (insulin infusion 6 pmol kg-1 min-1). 3. SNP infusion increased skeletal muscle blood flow by 86 % (P < 0.01), but skeletal muscle flow distribution and insulin-stimulated glucose uptake (61.4 +/- 7. 5 vs. 67.0 +/- 7.5 micromol kg-1 min-1, control vs. SNP infused leg, not significant), as well as flow distribution between different tissues of the femoral region, remained unchanged. The effect of SNP infusion on blood flow and distribution were unchanged during infusion of physiological levels of insulin (duration, 150 min). 4. Despite a significant increase in mean blood flow induced by an intra-arterial infusion of SNP, glucose uptake and flow distribution remained unchanged in resting muscles of healthy subjects. These findings suggest that SNP, an endothelium-independent vasodilator, increases non-nutritive, but not nutritive flow or capillary recruitment.