Histoarchitecture and Δ5-3β hydroxysteroid dehydrogenase profile in ovaries of the non-pregnant, pregnant and lactating insectivorous rat-tailed bat, Rhinopoma microphyllum kinneari

Abstract

AbstractThe histoarchitecture and profile of Δ5-3β hydroxysteroid dehydrogenase were studied in an insectivorous seasonally-breeding microchiropteran, Rhinopoma microphyllum kinneari (rattailed bat) ovaries during non-pregnant, pregnant and lactation phases. Mid-sections of follicles and ova showed variation in their diameter (0.013-0.182 mm and 0.010-0.075 mm, respectively). Though dextral and sinistral ovaries are functionally equivalent, ovulation occurs only once (alternately from one ovary) in each annual cycle. An extroverted corpus luteum (0.792 mm) was observed in either the dextral or sinistral ovary of a pregnant R. m. kinneari. This exhibited two types of cells. Follicular atresia was pronounced in ovaries during these reproductive stages. No post-partum 'heat' was discerned. Δ5-3β HSDH is a crucial catalyst in steroid hormone biosynthesis and the reaction product indicates status of steroidogenesis in different follicle types. Differential Δ5-3β HSDH activity evident from reaction product staining in three reproductive states and in different ovarian components was seen. Consistent sites of enzyme activity were thecal cells and ovarian stroma. However, intensity varied in different reproductive states.