The actions of ethinyloestradiol on the pituitary‐adrenal system of the rat

Abstract

Summary1. Single doses of ethinyloestradiol stimulate the pituitary adrenal axis of the female rat during quiescent conditions. 2. After a stimulus which releases endogenous ACTH, there is an inhibition of the release of corticosterone from the adrenal gland, but an increase in the corticosterone stored in the gland.3. Ethinyloestradiol (1V0 mg/kg) injected acutely or daily for 7 days does not affect the corticosterone bindinlg capacity of plasma in female rats, or the clearance rate of an injection of corticosterone. 4. Prolonged treatment with ethinyloestradiol and ACTH inhibits the pituitary-adrenal response to a stress and to an ACTH injection, indicating a block at the adrenal and pituitary level. 5. The adrenal gland recovers more rapidly than the pituitary after cessation of the oestrogen treatment. 6. The inhibition of the pituitary-adrenal response to stress after oestrogen is probably caused by inhibition of cholesterol synthesis as suggested by others. Oestrogens can increase corticoid secretion during non-stress conditions, however, so precursor lack through exhaustion cannot be excluded. 7. It is suggested that the inhibition of the stress response after prolonged ACTH treatment is due to a decrease in sensitivity of the adrenal cortex after frequent ACTH stimulation, but the possibility that it is due to a reduction in circulating cholesterol cannot be ruled out.

Recovery of hypothalamo‐pituitary‐adrenal function in the rat after prolonged treatment with betamethasone

“…The circadian rhythm in plasma corticosterone concentration was also studied as described by Hodges & Mitchley (1970a). Corticosterone production by the adrenal glands in vitro was measured using the method of van der Vies, Bakker & de Wied (1960), modified by Flack (1970). Adrenal glands were removed rapidly under ether anaesthesia, cleaned and weighed.…”

Suppression of adrenocorticotrophic activity in the ascorbic acid deficient guinea‐pig

“…Adrenal glands Right adrenal glands, removed immediately after the collection of the blood samples, were prepared for the determination of their cortisol content (Hodges & Hotston, 1970) and left adrenals for measuring the cortisol production in vitro using a modification of the method of Bakker & de Wied (1961) as described by Flack (1970).…”

Some Metabolic Actions and Possible Toxic Effects of Hormonal Contraceptives in Animals and Man

“…Pregnancy or the administration of oestrogens or oral contraceptives causes an increase in the plasma level of transcortin in women (De Moor et al 1966;Katz 8c Kappas 1967;Doe et al 1967;Musa et al 1967). In the rat treatment with ethynyloestradiol for 7 days did not increase corticosterone binding capacity, and high doses of oestrogen given for 14 days produced only a small increase in this globulin (Flack 1970). The effect of oral contraceptives in increasing the plasma level of transcortin in women results in a concomitant increase of bound 17-hydroxycorticosteroids (17-OHCS) and thereby total plasma cortisol (Layne et al 1962;Metcalf 8c Beaven 1963;Streeten et al 1969;Williamson 8c Moody 1970;Beck et al 1972).…”