In-vitro studies of the development of pituitary and testicular functions in diabetes (C57Bl/KsJ-db/db) mutant mice.

The hypothesis that male diabetes mutant mice (C57Bl/KsJ-db/db) are suffering from impairment of testicular steroidogenic function and pituitary LH release was tested. A smaller postpubertal increase of testicular weight and a reduction of plasma testosterone and androstenedione levels by 65% at 17 weeks of age were most obvious from the comparison to homozygous lean controls. The ability of constant amounts of Leydig cells, either in crude interstitial cell or in purified Leydig cell suspensions, to respond to maximal doses of hCG or cyclic AMP-was reduced by at least 40% in adult diabetes mice. This defect could be attributed to a 40% decrease of steroid-17 alpha-monooxygenase activity as compared to lean mice. No differences occurred, however, if Leydig cells were submaximally stimulated. GnRH-stimulated pituitary LH release was not significantly changed. The impairment of testicular steroidogenic function in diabetes mutant mice may represent a further aspect of infertility of these animals and of diabetes mellitus.