| Abstract: | The regulation of testicular hCG binding and steroidogenesis in adult mutant mice with hereditary diabetes and obesity was studied. Low doses of hCG caused no change in hCG binding in obese (ob/ob) mice, whereas, in diabetic (db/db) mice, the increase in binding measured 24 h after hCG administration was not as great as in normal males. Intermediate doses of hCG caused a decrease in hCG binding in obese and normal mice, but not in diabetic animals. However, 72 h after injection of intermediate doses of hCG, a decrease in hCG binding also was observed in diabetic mice. Plasma testosterone was elevated 24 h after hCG injection in all types of mice studied, but the increase in diabetic mice was smaller than in normal animals. However, 72 h after treatment with hCG, plasma testosterone was still elevated in diabetic mice, but not in normal males. In vitro, hCG stimulated testicular testosterone synthesis in all groups of mice, but the observed increase was smaller in diabetic and obese than in normal animals. Plasma LH levels were higher in diabetic than in normal mice, whereas plasma FSH and prolactin levels were lower in obese mice than in normal animals. All parameters (i.e., LH receptors and circulating hormone levels) measured in yellow (Ay/a) mice were similar to those in normal (a/a) mice. The present study indicates that in these models for noninsulin-dependent diabetes, the testicular metabolism of LH receptors and capacity to secrete steroids is altered. |
