The effect of ACTH on the blood clearance rate of aldosterone, cortisol, 17α-hydroxyprogesterone and 17α,20α-dihydroxy-4-pregnen-3-one in the sheep

Abstract The blood clearance rate (BCR) of aldosterone, cortisol, 17α-hydroxyprogesterone (17αOHP) and 17α,20α-dihydroxy-4-pregnen-3-one (17α20αOHP) has been measured in conscious sheep prior to and after 5 or 6 days ACTH treatment. ACTH increased the BCR of cortisol but did not change the BCR of the other three steroids. 17αOHP had a BCR greater than liver blood flow suggesting extra-hepatic metabolism. In vivo conversion of 17αOHP to 17α20αOHP by ovine red cells has been shown to be a significant site of this metabolism. It is suggested that this conversion of 17αOHP to 17α20αOHP may be important in the expression of the “hypertensinogenic” effect of 17αOHP.