Laurence C. Wegienka

Effect of arginine on serum levels of insulin and growth hormone in obese subjects

Abstract After the infusion of argine, serum levels of immunoreactive human growth hormone increased only slightly in obese subjects, reaching a peak value at 60 minutes of 7.9 ± 2.5 ng./ml. (mean ± S.E.M.) vs. 28 ± 6 ng./ml. in normal subjects, in spite of comparable rises in serum levels of α-amino-nitrogen. In contrast, changes in serum levels of immunoreactive insulin were similar in both groups, with a peak value at 30 minutes of 144 ± 50 μU/ml. in obese and 145 ± 17 μU/ml. in normal subjects.

Effect of selected hexoses, of epinephrine and of glucagon on insulin secretion in man.

Immunochemical methods of measuring serum insulin have implemented studies in man confirming in vitro data which suggest that metabolizable sugars such as mannose and glucose cause insulin secretion, whereas galactose, a nonutilizable sugar, does not. Infusions of 2-deoxy-D-glucose are associated with greatly increased epinephrine secretion and sustained hyperglycemia, but no rise in serum insulin levels. Epinephrine infusions induce and prolong hyperglycemia without raising serum insulin levels and effectively inhibit insulin secretion during glucose administration. These findings agree with in vitro evidence that epinephrine directly inhibits pancreatic secretion of insulin. Glucagon, on the other hand, sharply stimulates insulin secretion, either alone or after glucose infusions. Data are presented which suggest that this may be a direct effect of glucagon on the release of insulin by the pancreatic beta cell.

A clinically useful method for plasma testosterone determination

Abstract A simple method has been developed for clinically measuring plasma testosterone. Its sensitivity allows one to measure normal female levels of plasma, and the results are comparable to those obtained by double isotope derivative methods. This procedure requires paper chromatography of a methylene chloride extract of plasma and final determination by the competitive protein-binding technique, using salt precipitation of the bound fraction. By this method, the normal range for plasma testosterone was 26 to 108 mμg/100 ml in females and 273 to 1211 mμg/100 ml in males.

Comparison of insulin and 2-deoxy-D-glucose-induced glucopenia as stimulators of growth hormone secretion

Abstract Responses of plasma growth hormone after insulin-induced hypoglycemia and 2-deoxy-D-glucose (2-DG)-induced glucopenia were studied in 10 normal, 6 obese, 8 acromegalic, 6 addisonian, and 2 hypopituitary subjects. After insulin hypoglycemia, the mean increases of growth hormone above basal levels were: normal 27.6, addisonian 38.8, obese 2.3, active acromegalic 9.9, and inactive acromegalic subjects 3.1 mμg./ml. After 2-DG-induced glucopenia, the mean increases of growth hormone above basal levels were: normal 19.1, addisonian 25.6, obese 0.6, active acromegalic 6.5 and inactive acromegalic subjects 2.7 mμg./ml. No increase was noted with either stimulus in a hypopituitary subject. Both stimuli were effective in releasing growth hormone from the pituitary. The increase in growth hormone levels was higher and more consistent after insulin-induced hypoglycemia than after 2-DG-induced glucopenia. 2-DG, however, did produce a more sustained increase in growth hormone levels. In those subjects who have impaired insulin sensitivity, 2-DG—which acts by inducing cellular glucopenia—should be useful in evaluating pituitary growth hormone reserve.

Testosterone Metabolism in Idiopathic Hirsutism

Excerpt The recent development of methods for measuring testosterone in both the blood and the urine (1-6) has made possible a new approach to the problem of diagnosis in idiopathic hirsutism. This...

Gas chromatographic method for the determination of testosterone in urine

Abstract A method is described for measuring testosterone in the urine using glucuronidase hydrolysis, continuous extraction with methylene dichloride, and chromatography on silica gel column as well as thin-layer and gas chromatography. This method proved to be practical for processing large numbers of samples and gave consistently reproducible results in the more than 600 specimens tested in the course of clinical evaluation of patients.

In vitro Studies of the Mechanism of Polyuria Induced by Dextro Propoxyphene (Darvon).

Summary The isolated surviving toad bladder was used to demonstrate direct peripheral antagonism between antidiuretic hormone and both dextro propoxyphene (Darvon®) and levo propoxyphene (Norvad®). These findings suggest that the polyuria accompanying a recent death after dextro propoxyphene ingestion was a result of drug-induced nephrogenic diabetes insipidus.