Histochemical studies on three gonadotrophin-responsive enzymes in the infantile mouse ovary

The activities of alkaline phosphatase, NAD diaphorase and NADP diaphorase increased in infantile mouse ovaries in response to injected gonadotrophins. The distribution and activity of these enzymes were studied in detail in the ovaries of normal mice from 1 to 41 days after birth and in mice injected at various ages with FSH, LH and HCG. Granulosa cells contained NAD and NADP diaphorases. Thecal cells contained NADP diaphorase and alkaline phosphatase with NAD diaphorase first appearing in the thecae of larger follicles 11 days after birth. All three enzymes occurred in interstitial tissue, in the interfollicular stroma and in groups of gonadotrophin-responsive cells in the medulla. These medullary cells and the interstitial tissue were stimulated by exogenous LH and HCG but not by FSH. Granulosa, theca and interfollicular tissue were stimulated at some stage by each of the three injected hormones. The normal pattern of development is discussed in relation to the changing serum levels of endogenous gonadotrophin found in similar mice. It is concluded that the enzyme changes were closely and reciprocally related to endogenous hormone concentrations.