The effects of the genotype and social stress on cAMP- and substrate-dependent mechanism regulating the hormone-producing function of mouse testes

Several steps of cAMP- and substrate-dependent testosterone production in t he testes were studied with laboratory mouse micropopulations of six inbred strains (A/He, CBA/Lac, C57B1/6J, DD, YT, PP). The strains differed in bas al testosterone production in the gonads and in its response to activation of the adenylate cyclase signal transduction pathway at various steps by hu man chorionic gonadotropin (hCG), the cholera toxin, forskolin, and dibutyr yl-cAMP and in the presence of pregnenolone, an early precursor of testoste rone. Establishment of dominant-subordinate relationships in mouse populati ons substantially affected testosterone production in response to all activ ators of testicular steroidogenesis. The secretory activity of the testes d ecreased at the early establishment of social hierarchy in experimental mic ropopulations, then returned to the initial level, and again decreased in t he case of activation with hCG, dibutyryl-cAMP, and pregnenolone. With all activators of steroidogenesis, basal and activated testosterone production changed in the same direction during the establishment and maintenance of s ocial hierarchy, suggesting coordinated changes in all examined steps of te stosterone biosynthesis in the testes. The among-strain differences in resp onse to all activators of steroidogenesis remained much the same at various stages of the establishment of social hierarchy. The parameters of cAMP- a nd substrate-dependent testosterone production averaged over individual sta ges of the establishment of social hierarchy proved associated. Their genot ypic correlations were positive and, in many cases, significant. Subsequent component analysis showed that one principal component accounted for more than 80% of the total among-strain variation, suggesting a coordinated gene tic control of the endocrine function of the testes.