Effects of different gestagenic steroid types on plasma-free corticosteroid levels in ACTH-treated rats

Abstract Eight selected gestagens were tested for effects on adrenal weight and plasma cortiosteroid levels following ACTH injection in intact male and female rats. Five patterns emerged which were suggestive of alterations in adrenocortical function and/or pituitary-adrenal relationships: 1. 1. Depression of adrenal weight and subnormal plasma corticosteroid levels following ACTH injection (males and females; 17 α-hydroxy-6 α-methylpregn-4-ene-3, 20-dione acetate, 3-cyclopentyloxypregna-3, 5-dien-20-one); 2. 2. Reduction of adrenal weight but normally elevated plasma corticosteroids after ACTH (females; 17 α-ethyl-17 β-hydroxyestr-4-en-3-one); 3. 3. No change in adrenal weight but subnormal plasma corticosteroids following ACTH-treatment (males; pregn-4-ene-3, 20-dione); 4. 4. Adrenal hypertrophy with subnormal plasma corticosteroid levels under the influence of ACTH (females; 17 α-ethynyl-17 β-hydroxyestr-4-en-3-one, 17 α-ethynyl-17 β-hydroxyestr-5(10) -en-3-one); 5. 5. Adrenal hypertrophy with normally elevated plasma corticosteroids following ACTH (males; 17 α-ethynyl-17 β-hydroxyestr-4-en-3-one, 17 α-ethynyl-17 β-hydroxyestr-5(10)-en-3-one). Only the first category (depressed adrenal weights and subnormal elevation of plasma corticosteroids following ACTH injection) resembles the feedback pattern obtained with glucocorticoids.