The effect of elevated serum thyroid hormone concentrations on insulin-induced glucose metabolism was studied in healthy subjects before and after T4 administration (250 micrograms T4/day for 10-14 days). This treatment induced moderate hyperthyroidism (T4, 15.2 micrograms/dl; T3, 200 ng/dl). The following results were obtained. Insulin receptor binding to a 90% enriched monocyte fraction or to mitogen-stimulated cultured T lymphocytes was decreased by T4 administration, whereas insulin binding to erythrocytes was unaffected. Despite down-regulation of cellular insulin receptors, T4 administration did not alter oral glucose tolerance, but increased the disappearance of glucose after an iv load and the amount of glucose metabolized during euglycemic clamp studies infusing 1.0 or 1.5 mU insulin/kg BW X min; no effect was found at insulin infusion rates of 0.5, 2.0, and 4.0 mU/kg X min. At increasing steady state plasma glucose levels (up to 175 mg/dl) and an insulin infusion rate of 1.0 mU/kg BW X min, T4 administration reduced insulin-induced glucose metabolism. We conclude that experimental hyperthyroidism decreases insulin receptor binding but increases insulin-induced glucose metabolism during euglycemia. This may be due to the direct effect of thyroid hormones on glucose metabolism; however, during hyperglycemia, thyroid hormone induced insulin resistance is unequivocal.

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By using a modified Scatchard analysis, statistically significant differences were observed between the receptor affinities of the groups A aiid D, B and D, A and C.The receptor affinities and concentrations were not significantly different between the follicular and the luteal phases. From the data, no inverse correlation between the plasma insulin concentration and receptor binding was seen, i.e. the phenömenon of downiegulation pf insulin receptor concentration with hyperinsulinaemia seemed not to apply to erythrocytes.The present results suggest that insulin binding to erythrocytes is mpdulated preferably or even exclusively by an alteration of receptor affinity and that short-term chariges in insulin binding to erythroeytes are not caused by an alterätion of receptor concentration. Vergleich der Bindung von Insulin an Erythrocyten während und nach Schwangerschaft und in der Proliferationsund der Sekretionsphase des Menstruations-Cyclus

In two double-blind studies 66 insulin-dependent diabetic subjects pretreated with pork insulin were changed to human insulin (recombinant DNA) or a purified pork insulin preparation (regular and NPH insulin). Sixty-five patients previously pretreated with beef insulin were transferred, in a randomized, double-blind fashion, to human insulin and purified beef insulin of the same preparations (regular and NPH insulin). Patients' metabolic control, as demonstrated by fasting and 1-h postprandial blood glucose, HbA1c, and daily insulin dosage, over 4 mo was unchanged in our four groups compared with the values before changing insulin preparation. No severe hypoglycemic attacks or skin reactions were reported.

Capillary radioimmunoassay -- a modification of the coated tube technique -- is described. The assay is equivalent (accuracy, sensitivity, precision) to conventional methods for insulin determination; it overcomes, however, the necessity of centrifugation or filtration and offers the added bonus of being automation compatible.

Summary:  30 amino acids and their derivatives could be found in the ejaculates of humans by ion‐exchange chromatography. There were significant differences between diabetics and controls in the levels of theonine, serine, glutamine, glycine, iso‐leucine, leucine, tyrosine, phenylalanine, histidine and in 3‐methyl‐histidine. There was a positive correlation between levels of certain amino acids and the number of pathologically motile spermatozoa, particularly microforms and head alterations. An impaired Krebs cyclus function may explain an elevation of amino acid levels as they are utilized mainly by this cycle, which function depends on intact substrate flow from glucose catabolism.

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