We have compared the plasma profiles of C-peptide, human insulin (recombinant DNA), and purified porcine insulin of pancreatic origin (PPI) in six nondiabetic men after low-dose (4.8 U) or high-dose (9.6 U) subcutaneous injection and low-rate (1.0 U/h) or high-rate (1.7 U/h) intravenous infusion. There was no significant difference in plasma C-peptide or glucose levels when human insulin was compared with PPI at either dose level for subcutaneous injection or intravenous infusion. Thus, there was equal suppression of endogenous insulin by the two species of exogenous insulin. For low-dose subcutaneous injection there was no significant difference between plasma insulin levels of the two species at single time points or when areas were compared. For high-dose subcutaneous injection mean plasma insulin levels were higher after human insulin than after PPI (20-300 min); this serial difference reached conventional statistical significance at 50 min (P less than 0.05) and 90 min (P less than 0.01). For the area under plasma insulin profiles between 0 and 90 min after high-dose s.c. injection, human insulin was higher than PPI (P = 0.06). There was no significant difference between insulin concentrations after human insulin and PPI given by either low- or high-dose intravenous infusion, except that high-dose PPI values (55-110 min) were slightly but significantly higher after high-dose intravenous infusion. Further comparisons of the pharmacokinetics of human and other species of insulin are, therefore, justified in larger numbers of subjects and particularly in diabetic individuals.

Animals↗

PubMedDate not supplied

Recent progress in the development of radioimmunoassays for human serum lipoproteins.

A review of radioimmunoassays for measuring human apolipoprotein B (apo B), the A apolipoproteins of high density lipoprotein (apo A-I and apo A-II) and apolipoprotein C-II (apo C-II) in human plasma and in isolated lipoproteins is presented. The sensitivity, specificity and validity of each of these assays is discussed. In normolipidemic subjects the reported serum apo B concentrations ranged between 0.83 +/- 0.16 and 0.92 +/- 0.21 g per l (m +/- SD). Serum apo B concentrations were highest in Type II subjects (Type IIa homozygotes 3.83 +/- 0.43 g per l; Type IIa heterozygotes 2.37 +/- 0.47 g per l) and were less elevated in patients with Type IV and Type V disorders (1.32 +/- 0.21 g per l and 1.26 +/- 0.30 g per l, respectively). Preliminary data on the relationship between plasma apo B and cholesterol, the distribution of apo B amongst the lipoprotein classes and a comparison of the lipoprotein lipid-apo B ratios in the various hyperlipidemic disorders are summarized. In contrast to apo A-II, the immunoreactivity of apo A-I was not fully exposed in whole sera and in isolated lipoproteins. The different methods used to measure the apo A-I immunoreactivity are discussed. In normolipidemic subjects the serum apo A-I concentration in males and females was 1.13 +/- 0.061 and 1.24 +/- 0.068 g per l (m +/- SD), respectively, while the corresponding serum apo A-II values were 0.35 +/- 0.038 g per l and 0.41 +/- 0.046 g per l. In subjects with Tangier's disease, the serum apo A-I and apo A-II concentrations were less than 1 percent and 5 to 7 percent of that found in controls. The serum apo A-I level was also reduced in two subjects with abetalipoproteinemia (0.38 g per l and 0.30 g per l) and Tye II hyperlipoproteinemia (range 0.54 to 0.86 g per l). In normotriglyceridemic subjects and those with Type IIa hyperlipoproteinemia, the total plasma apo C-II concentrations were 0.0497 +/- 0.0040 g per l and 0.0562 +/- 0.0054 g per l (m +/- SE). Plasma apo C-II levels in Type IIb, Type IV and Type V lipoproteinemic subjects were 0.0899 +/- 0.0046, 0.0854 +/- 0.0069 and 0.1328 +/- 0.0021 g per l, respectively and were significantly higher than in the normotriglyceridemic subjects. An analysis of the relationship between the apo C-II content and the lipoprotein lipase activator properties of VLDL isolated from normo- and hypertriglyceridemic plasma samples is presented.

Apolipoproteins↗

PubMedDate not supplied

Calcium infusion--a new provocative test for insulinomas.

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Adenoma, Islet Cell↗

PubMedDate not supplied

Post-mortem glycosylated hemoglobin (HbA1c): evidence for a history of diabetes mellitus.

Glycosylated hemoglobin (HbA1c) levels on blood obtained from 28 cadavers were compared with that of healthy volunteers and patients with diabetes mellitus. Levels of HbA1c did not correlate with post-mortem intervals of four to 36 hours, suggesting that HbA1c is stable under these conditions. All deceased with a history of diabetes mellitus, five cases, had an elevated post-mortem blood HbA1c. Twenty-three deceased had a negative history for diabetes mellitus and seven of this group had an elevated HbA1c. These seven cases had diagnosis of malignancies and a history of prolonged exposure to steroids in excess compared to the remaining 16 cases.

Adolescent↗