Adrenal steroidogenesis and hepatic corticosteroid metabolism in hypertensive rats

In vitro metabolism of progesterone and cholesterol by the adrenal glands and hepatic delta 4-reductase activity of SHR and ARH were investigated to clarify the possible hyperactivity of the pituitary-adrenal axis and abnormal steroid metabolism in SHR. The increased conversion rate of progesterone to 11 beta-hydroxyprogesterone, corticosterone and 18-hydroxy-deoxycorticosterone and the increased biosynthesis of pregnenolone from cholesterol were noted in ARH, which were similar to those seen with chronic ACTH administration. On the other hand, adrenal steroidogenesis in SHR showed no difference from that of control. Therefore the apparently normal adrenal steroidogenesis in SHR may suggest that the adrenal gland is not involved in the spontaneous hypertension of rats. The markedly decreased hepatic delta 4-reductase activity in ARH and SHR was observed in this investigation.