Histochemical Localization of Two Oxidative Enzymes in the Leydig Cells of Microchiropteran Bat Hipposideros speoris (Schneider) during the Annual Testicular Cycle

Hipposideros speoris is an insectivorous bat which breeds once in a year. The adult males show peak in their testicular activity from November-December, corresponding to the mid-December ovulation in the females. The testis of this bat was investigated for histochemical localization of succinic dehydrogenase and glucose-6-phosphate dehydrogenase in the Leydig cells. Specific changes in the enzyme reactions were observed correlative to the reproductive status. Thus, during the quiescent phase (April-August) proliferation of the atrophied Leydig cells was observed, along with a moderate activity of both the enzymes. With the approach of maturity (recrudescent phase: September-October) an enhancement in the enzyme activities was noticed. The onset of breeding period (November-December) brought about an abundance of Leydig cells and increase in the intensity of the enzyme reactions. During the post-mating phase (mid-December) the Leydig cells were not only regressed but decreased in abundance, with corresponding decrease in the localization of the enzymes. During the regression phase (January-March) there was a dramatic decrease in the abundance of the cells as well as intensity of reaction of the enzymes. It is concluded that G-6-PDH and SDH would generate NADPH that is needed for hydroxylation of steroids during steroidogenesis and the histochemical demonstration of these two enzymes provides an additional evidence for the steroid generating capacity of the Leydig cells, which follows a seasonal pattern.