Immunolocalization of cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase in the ovary of vespertilionid bat (Scotophilus heathi) during different phases of ovulatory delay.
Immunocytochemical localization of steroidogenic enzymes, cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase, was performed in the ovaries of Scotophilus heathi during reproductive cycle, with reference to the period of delayed ovulation. Moderate immunoreactivity of side chain cleavage enzyme and 17-alpha-hydroxylase was observed mainly in thecal cells and interstitial cells of the ovarian stroma during quiescence. Thecal cells positive for 17-alpha-hydroxylase were found even around the primary follicles. The peak immunoreactivity for all the three enzymes was observed during recrudescence. It coincided with high circulating steroid levels during this period. In the stroma, immunoreactivity for side chain cleavage and 17-alpha-hydroxylase was so extensive that it almost occupied the entire interfollicular area of the ovary. Aromatase immunoreactivity declined, but side chain cleavage enzyme and 17-alpha-hydroxylase remained extensive during the period of delayed ovulation. This suggests a high androgen and low estrogen synthesis during the period of delayed ovulation. There was a marked decline in 17-alpha-hydroxylase and an increase in aromatase immunoreactivity during the preovulatory period, suggesting a decrease in androgen and increase in estrogen synthesis. The results suggest thecal cells and interstitial cells of the stroma as the major site of steroidogenesis in the ovary of S. heathi. Over production of androgen is attributed to the extensive development of 17-alpha-hydroxylase positive interstitial cells in the ovarian stroma, and this may be responsible for delayed ovulation in Scotophilus heathi.
Abhilasha
Department of Zoology, Banaras Hindu University, Varanasi, India.
Krishna
A
A
D000818:Animals; D001141:Aromatase / Q000032:analysis* / Q000276:immunology; D002685:Chiroptera / Q000378:metabolism*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000032:analysis* / Q000276:immunology; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism*; D005260:Female; D010053:Ovary / Q000201:enzymology*; D010060:Ovulation / Q000378:metabolism*; D012621:Seasons; D013254:Steroid 17-alpha-Hydroxylase / Q000032:analysis* / Q000276:immunology; D013997:Time Factors
D003577:Cytochrome P-450 Enzyme System; D001141:Aromatase; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme