Recombinant DNA technology allows the production of insulin analogues with faster absorption rates from subcutaneous tissue as compared to conventional human regular insulin. We report the time-action profiles of 12 U subcutaneously injected insulin analogues (B9Asp + B27Glu or B10Asp) as evaluated against human regular insulin by means of the euglycaemic clamp technique (blood glucose 5.0 mmol/l) in healthy men. After injection of 12 U of either insulin preparation identical values were found for maximal insulin action (maximal glucose infusion rate, time to peak action), total amount of glucose infused as well as area under the curve of glucose infusion rate. Half-maximal glucose infusion rate was reached significantly earlier after injection of modified insulins (mean +/- SD 38 +/- 7 and 43 +/- 5 min) as compared to regular insulin (56 +/- 14 min, p less than 0.01). Forty-five min after injection of both insulin analogues glucose infusion rate had increased by 7.4 +/- 1.8 or 6.1 +/- 1.8 mg.kg-1.min-1, reflecting 83 +/- 27 or 67 +/- 15% of maximal regular insulin action. In conclusion, the two tested insulin analogues showed similar action profiles, but a significantly faster onset of action as compared to regular insulin.

Repeated plasma basal and glucagon stimulated C-peptide (CP) levels were determined at diagnosis, 1 mo. & 3-mos. intervals for 2 yrs in 72 newly diagnosed JDDM (38 M, 34 F)with a mean age of 12.1 ± 2.7 yrs. An analysis was performed of the correlation between basal and peak CP levels, HbA1 and daily insulin (I) dose at each period. According to basal and peak CP at 3 and 12 mos., three groups were differentiated: The following predictive factors for future insulin needs were found: a) basal CP levels at diagnosis of 0.15 pM/ml or more (Gr. A) are predictive for a long remission; b) a ratio of peak CP/I (exogenous) of less than 0.5 at 1 month (Gr. C) indicates no chance of remission and calls for progressive increase of insulin dose.

The mechanisms of sc insulin absorption are not understood, and models for interpreting in vivo data cannot be developed without gross simplification. To overcome this difficulty we developed a new approach which makes use of deconvolution analysis and does not require any model of the sc tissue. In five normal subjects and seven insulin-dependent diabetic (IDDM) patients endogenous insulin secretion was suppressed by means of a hypoglycemic glucose clamp procedure (approximately 2.8 mmol/L) sustained by a continuous insulin infusion (approximately 4 pmol/min.kg). A bolus injection of insulin (5.4 nmol) was administered iv, and plasma insulin concentrations were measured frequently for 2 h to assess iv insulin kinetics. Insulin then was injected sc in the abdominal region, and plasma insulin concentrations were measured for 8 h. Each subject was studied twice, with porcine and semisynthetic human insulin (Actrapid, Novo). The rate of insulin absorption was reconstructed by deconvolution from the plasma concentrations and iv insulin kinetic data. Linearity of the iv insulin kinetics, essential for deconvolution analysis, was confirmed by a dose-response study in the range of the measured concentrations (150-1800 pmol/L). In most instances, a two-compartment model was adequate to describe the iv response. The mean plasma insulin clearance rates were 15.5 +/- 1.9 (+/- SD) mL/min.kg (porcine) and 17.2 +/- 6.0 (human) in normal subjects and 20.7 +/- 8.8 (porcine) and 20.9 +/- 9.1 (human) in the IDDM patients. The rate of appearance of human insulin from sc tissue was faster than that of porcine insulin in both normal and IDDM subjects, but no significant differences were found in bioavailability, which was 55 +/- 12% (+/- SD; porcine) and 61 +/- 34% (human) in the normal subjects, and 84 +/- 28% (porcine) and 86 +/- 23% (human) in the IDDM patients. The rate of absorption and bioavailability were higher in the IDDM patients than in the normal subjects, a difference possibly related to increased sc blood flow in the IDDM patients. No differences were found with regard to glucose requirement values, normalized to plasma insulin concentrations, in agreement with the finding that the bioavailability of the two insulin species was similar.

To determine the role of proinsulin on endogenous insulin release, splanchnic output and arterial concentrations of C-peptide were measured in healthy subjects before and during infusion of human (HPI) and porcine (PPI) proinsulin at increasing rates for 70 min each (HPI, 328 and 656 micrograms X m-2 X h-1; PPI, 54, 134, and 268 micrograms/m-2 X h-1), while euglycemia was maintained by variable glucose infusion. By using this approach splanchnic C-peptide output was reduced by human proinsulin infusion from 143 +/- 16 (mean +/- SE) pmol/min to 111 +/- 18 and 75 +/- 11 pmol/min (P = 0.01). Simultaneously, arterial concentrations of C-peptide decreased from 716 +/- 40 pmol/l by 23 and 32%. Similar inhibition was induced by porcine PPI of splanchnic C-peptide output at an infusion rate of 268 micrograms X m-2 X h-1. Mean metabolic clearance rate was 2.7 and 3.7 ml X kg-1 X min-1 for HPI and PPI, respectively. Splanchnic glucose output was almost completely suppressed by human and porcine proinsulin at maximal infusion rates. This effect preceded both inhibition by proinsulin of splanchnic C-peptide output and stimulation of peripheral glucose utilization. We conclude that human and porcine proinsulin suppress endogenous insulin secretion at pharmacological concentrations. The observed constancy of the metabolic clearance rate of HPI demonstrates that its clearance remains a nonsaturable process up to supraphysiological HPI concentrations, while clearance of PPI appears to be subject to saturation. Furthermore, it appears that splanchnic glucose output responds earlier to proinsulin exposure than suppression of C-peptide release or stimulation of peripheral glucose utilization.

Peripheral hyperinsulinemia may be associated with metabolic consequences that could contribute to the high incidence of macrovascular disease in patients with diabetes mellitus. Arterial wall and striated muscle cells were studied in dogs to examine the effect of hyperinsulinemia on the lipid content and on lipogenic and glycolytic enzyme activity. Eight pancreatectomized dogs received segmental pancreatic autografts with venous drainage into the iliac vein. Glucose disappearance rates (K values) were normal four years after transplantation, but both fasting serum insulin levels (48.9 ± 4.8 v 11.8 ± 1.9 μU/mL) and the total area under the glucose-insulin response curve (1797 ± 196 v 1110 ± 158 μU · min/mL) were significantly greater than in control animals (P < 0.05). The hyperinsulinemic dogs had a marked triglyceride elevation in arterial smooth muscle (20.6 ± 8.0 v 0.5 ± 0.4 μmol/g) and striated muscle (171.4 ± 46.6 v 41.2 ± 7.7 μmol/g) (P < 0.001). Moreover, key enzymes in lipid synthesis (glucose-6-phosphate dehydrogenase, malic enzyme, and 3-hydroxyacyl-CoA DH) were significantly increased (P < 0.01) in the hyperinsulinemic animals, while the glycolytic enzymes, (phosphofructokinase, hexokinase, pyruvate kinase, and α-glycerophosphate DH) were not significantly different. These data demonstrate substantial enhancement of lipid synthesis in arterial wall and striated muscle in hyperinsulinemic dogs. Altered substrate metabolism in arterial walls, in association with hyperinsulinemia, may have important implications with regard to macrovascular disease in diabetes, particularly in insulin-treated patients. In addition, these studies may serve to stimulate longer term assessments of macroangiopathy in the increasing number of patients with functioning pancreatic allografts draining into the systemic circulation.

The comparative potency of equimolar amounts of soluble porcine and semisynthetic human insulin were studied in ten patients with type 1 diabetes in acute experimental situations. In both situations residual subcutaneous insulin depots were eliminated by intramuscular treatment exclusively with soluble insulin four days before the experiments. Then, practically identical metabolic states were achieved by connecting the patients to a glucose-controlled insulin infusion system (Biostator) 12 hours before the study. In one study, 0.5 g/kg body weight of glucose was administered intravenously as a bolus, and thereafter insulin was infused at a rate of 1.0 mU/kg/min. The decline in blood glucose was rectilinear and identical for the two insulins: y = -1.18x + 206 and y = -1.17x + 205. The insulin effect is well below maximum, and a 10% increase in the infusion rate of insulin was easily detected. Although changes in blood glucose and pancreatic glucagon were identical, a significantly lower plasma growth hormone level was noted after human insulin infusion. In the second study, 24 hours of near-normoglycemia was attained by the glucose-controlled insulin infusion system, the patients being supine and having identical meals at identical intervals. The diurnal blood glucose, plasma growth hormone, and pancreatic glucagon patterns were identical and the total 24 hour insulin consumption was 47.7 +/- 3.5 units and 47.7 +/- 3.7 units for the two insulins.

It has recently been shown that conventionally treated IDDMs are insulin resistant. Using the insulin clamp technique, we studied the influence of metabolic status on the in vivo insulin effect in these patients. Eleven IDDMs, treated conventionally with diet and insulin for 10.7 ± 5.6 yr, were studied before and after continuous subcutaneous insulin infusion (CSII) treatment (with a portable pump) for 6 mo. We found that conventionally treated diabetic subjects were extremely insulin resistant with regard to peripheral glucose uptake. Glucose uptake, at an insulin concentration of about 80 μU/ml, was 4.3 ± 2.0 mg/kg · min before treatment compared with 11.5 ± 4.0 mg/kg · min in normals (P < 0.01). After pump treatment for 6 mo, metabolic control improved significantly (HbA1c decreased from 8.9 ± 1.9% to 7.4 ± 1.2%, P < 0.01) and, parallel to that, glucose uptake increased about 80% to 7.5 ± 3.5 mg/kg · min (P < 0.01). The mean daily plasma FFA level decreased from 0.32 ± 0.10 mmol/L to 0.21 ± 0.07 mmol/L (P < 0.01); this variable was negatively correlated to the glucose clearance rate (r = –0.62, P < 0.01). There was no statistically significant change in mean daily plasma insulin and plasma growth hormone levels or in 24-h cortisol excretion in the urine (P > 0.1). The insulin binding capacity of serum IgG was also unchanged, and there was no significant relationship between this quantity and glucose clearance rates (r = 0.18, P > 0.1). We conclude that conventionally treated IDDMs are insulin resistant with regard to peripheral glucose uptake. The insulin resistance may, at least in part, be secondary to the abnormal metabolic Status Of these patients.

Several factors indicate that autoimmune mechanisms may play a part in the aetiology of insulin-dependent diabetes mellitus. At the onset of the disease in 10 children (aged 11-16 years) plasmapheresis was performed four times over one to two weeks. Seventeen age-matched children with the same clinical features served as controls. The C-peptide concentrations at onset were the same in the two groups, but after one month the children treated with plasmapheresis had significantly higher values. This difference became even more pronounced after three, nine, and 18 months, both during fasting and at the maximum response to a standardised meal. The study group also had a significantly more stable metabolism, longer partial remission, and no higher insulin requirement. Of the 10 treated children islet-cell cytoplasmic antibodies were present in seven before plasmapheresis and in nine during treatment. The antibodies remained detectable in five and six out of nine patients at one and six months respectively after plasmapheresis. Although the mechanisms are obscure, plasmapheresis performed at the onset of insulin-dependent diabetes mellitus may help to preserve beta-cell function.

This study examined pancreatic allograft function in transplanted diabetic juvenile pigs. The grafts were transplanted with ligated, occluded (Ethibloc) or open ducts. No immunosuppression was used. Irreversible and permanent diabetes was induced by streptozotocin. Graft function was assessed by measuring glucose tolerance and insulin production during an i.v. glucose tolerance test. The fractional growth rate of the transplanted host was used to evaluate the long-term consequence of transplantation. Normal glucose tolerance was achieved in 50%, and a slight impairment in 10% of the animals. In 35%, no detectable graft function was observed. Duct-ligated and Ethibloc-occluded grafts had a significantly lower function rate within the first week compared with grafts with open ducts. The fractional growth rate was significantly decreased in animals receiving grafts with occluded ducts. This was probably not due to different insulin production. No graft failures were observed within the first week in open-duct graft transplantations. Graft failures were associated with elevated serum alpha-amylase and were probably due to vascular impairment. Normal glucose tolerance in transplanted pigs was associated with elevated levels of normal insulin and C-peptide in peripheral blood, concomitant with low levels of proinsulin. Our results show that a pancreatic graft should be transplanted with open ducts. Obstructed ducts lead to an increased frequency of graft failure, while the transplanted hosts with such functioning grafts show retarded growth due to unidentified factors.

Scandinavian Journal of ImmunologyVolume 17, Issue s10 p. 273-278 Quantitative Radioimmunoelectrophoresis for Determination of Binding to IgG of Insulin and Other Polypeptides A. H. CHRISTIANSEN, A. H. CHRISTIANSEN Department of Dermatology, Finsen Institute, Copenhagen, and Novo Research Institute, Bagsværd, Denmark Deceased.Search for more papers by this authorL. HEDING, L. HEDING Department of Dermatology, Finsen Institute, Copenhagen, and Novo Research Institute, Bagsværd, DenmarkSearch for more papers by this author A. H. CHRISTIANSEN, A. H. CHRISTIANSEN Department of Dermatology, Finsen Institute, Copenhagen, and Novo Research Institute, Bagsværd, Denmark Deceased.Search for more papers by this authorL. HEDING, L. HEDING Department of Dermatology, Finsen Institute, Copenhagen, and Novo Research Institute, Bagsværd, DenmarkSearch for more papers by this author First published: December 1983 https://doi.org/10.1111/j.1365-3083.1983.tb04029.xCitations: 1 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume17, Issues10December 1983Pages 273-278 RelatedInformation

B-cell function was studied in 20 diabetic children, with an age at onset of diabetes between 1–16 years (8.8 ± 4.0). Serum samples were taken before the first insulin injection and after 1, 3, 6, 9 and in a few patients after 18 months. At 3, 9, and 18 months the patients were also given a standardized breakfast load. Serum proinsulin, C-peptide, IRI and insulin antibodies (IgG) were determined. At onset 19 patients had measurable C-peptide (0.22 ± 0.17 pmol/ml; range 0.05–0.58). Proinsulin varied between 0.000–0.25 pmol/ml (0.069 ± 0.071) and at onset amounted to 31.3 ± 29.4 (0–100)% of C-peptide as compared to 3.3 ± 1.1 (1.7–6.6) in non-diabetics. A long partial remission was significantly correlated to a low proinsulin/C-peptide ratio at onset. In patients with low fasting proinsulin and no insulin antibodies, breakfast stimulation was accompanied by an increased proinsulin release at 3 and 9 months. The results suggest that abnormal proinsulin secretion is a feature of the ‘B-cell exhaustion’ complex in juvenile-onset diabetes.

The effect of standing and physical exercise and catecholamines and cyclic nucleotides in plasma was measured in 8 patients with essential hypertension under standardized conditions before and after prolonged treatment with clonidine. Before clonidine medication noradrenaline, adrenaline and cyclic AMP (cAMP) increased in response to standing and bicycling for 20 min. No significant correlation was found between their absolute levels nor was the increase in cAMP following exercise correlated to the increase in noradrenaline. Standing and physical exercise were without effect on cyclic GMP (cGMP). Clonidine reduced the plasma noradrenaline concentration in supine position and the noradrenaline and the adrenaline response to standing and exercise. Plasma cAMP was uneffected by clonidine under basal conditions but the response to exercise was slightly reduced initially. During clonidine there was a positive correlation between the plasma levels of cAMP and noradrenaline following work. Clonidine produced an increase in plasma cGMP in supine position, immediately prior to bicycling and after 5 min of exercise.