Adrenocortical Modulation Following ACTH, Corticoid, and Medullary Hormone Administration in the Soft-shelled Turtle Lissemys punctata punctata (Bonnoterre) (Family: Trionychidae)

Our aim was to study the role of ACTH and adrenal hormones in adrenocortical function in the soft-shelled turtle, Lissemys punctata punctata (Family: Trionychidae). All experiments were carried out in sexually immature animals. 1) ACTH treatment at all doses (0.5, 1.0, and 2.0 IU/100 g body wt. daily for 10 d) produced adrenocortical hypertrophy with increased nuclear diameters followed by a rise in acid and alkaline phosphatase activities, and depletion of cholesterol and ascorbic acid levels from the adrenal gland. The magnitude of the response was nearly the same for all doses. 2) Dexamethasone treatment only at the moderate or higher dosage (50 or 100 mu g/100 g body wt. daily for 10 d) suppressed adrenocortical activity by causing changes counter to those of ACTH, and showed dose-dependent action, with no significant effect at the lower dose (25 mu g/100 g body wt. daily for 10 d). But ACTH treatment (0.5 IU/100 g body wt. daily for 10 d after DMS treatment of 100 mu g/100 g body wt. daily for 10 d) prevented adrenocortical suppression by inducing the same manifestations as those of ACTH alone in dexamethasone (DMS) recipients. 3) Corticosterone and aldosterone administration only at the moderate or higher dose (50 or 100 mu g/100 g body wt. daily for 10 d) had dose-dependent inhibitory effects on adrenocortical function by causing changes that were the same to those of dexamethasone recipients. 4) Norepinephrine and epinephrine treatments, however, caused dose-dependent adrenocortical stimulation only at the moderate or higher dose (50 or 100 mu g/100 g body wt. daily for 10 d) by inducing changes that were comparable to those of ACTH. These findings are briefly discussed.