Seasonal Adrenocortical Cycle of the Female Soft-shelled Turtle Lissemys p. punctata

Abstract

The seasonal adrenocortical cycle in the female soft-shelled turtle Lissemys p. punctata was investigated by examining the adrenal gland once a month throughout the year from gravimetric, histological, histochemical and biochemical standpoints. The adrenal gland weight, nuclear diameter, histochemically detected 3b-hydroxysteroid dehydrogenase activity, corticosterone and RNA concentrations, and acid phosphatase and alkaline phosphatase activities began to increase from early summer (March-June), reached a peak in late summer (July-August) and declined subsequently (September-February), but adrenal cholesterol and ascorbic acid levels together with histochemically demonstrated sudanophilic lipids were altered reversely to those of other parameters. The results indicate that adrenocortical activity varies seasonally, being higher in early summer, highest in late summer and low in winter, that coincides with the seasonal ovarian cycle in Lissemys. It is suggested that there is a correlation between ovarian and adrenocortical activity and that the seasonality in adrenocortical activity may be related to environmental (temperature) and hormonal factors in the soft-shelled turtle.