INFLUENCE OF GONADOTROPHIN ON HISTOCHEMICAL PROPERTIES OF THE RABBIT OVARY

Abstract

ABSTRACT Histochemical findings on rabbit ovarian tissue following gonadotrophin stimulation were correlated with the extent of acetate-1-14C incorporation into steroids by ovarian slices incubated at equivalent time-periods. Gonadotrophin reduced the rate of cellular division (tritiated thymidine uptake) in the maturing follicle, and following ovulation, cellular division was seen principally in the theca interna and lutein cells. Cellular division was not seen in the cells of the interstitium before or at any time after gonadotrophin stimulation. Gonadotrophin intensified the Δ5, 3β-hydroxy-steroid dehydrogenase while reducing the 17β-hydroxysteroid dehydrogenase reaction. The intensity of the reductases may reflect an increased synthetic activity of the cells of the interstitium for the C21-class of steroids and a decreased synthesis of the C19-class of steroids. A histochemical reaction for 20β- (but not 20α-) hydroxysteroid dehydrogenase intensified after gonadotrophin, suggesting limited amounts of the 20β-hydroxy epimer being formed, and the balance of the reactions favouring an increased formation of progesterone and 20α-hydroxy-pregn-4-en-3-one. These studies suggest the cell types involved in the synthesis of progestins and androgens and indicate that the cells of the interstitium do not proliferate following gonadotrophin.