A comparison of the pituitary inhibitory effects of prednisone, prednisolone, and hydrocortisone

Prednisone, prednisolone and hydrocortisone, administered in doses of 1 mg. daily for thirty days, depressed the growth rate of rats. Prednisolone and hydrocortisone caused atrophy of the adrenal glands and increased the relative weights of the thyroid glands and testes. The apparently similar effects produced by prednisone were not significant. The seminal vesicles were not affected significantly by prolonged administration of prednisone, prednisolone or hydrocortisone. Pretreatment of rats with these steroids prevented the adrenal ascorbic acid depletion normally caused by laparotomy under ether anaesthesia. Prednisolone was slightly more potent and prednisone was considerably less potent than hydrocortisone in producing these effects.

Anterior pituitary glands in patients treated with cortisone and corticotropin

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Effect of chlorpromazine on pituitary ACTH secretion in the dog

Effect of chlorpromazine on adrenal cortical function has been determined by measuring 17-hydroxycorticosteroids in adrenal venous blood of dogs following intravenous injection of the drug. It was found that approximately half of the animals had significant adrenal responses to the injection of 1.3–3.3 mg./kg of chlorpromazine, and that all animals responded to dosages of 3.5 mg./kg and above. The adrenal response was abolished by hypophysectomy, ruling out a direct action of the drug on the adrenal gland. The response was unaffected by maintaining high peripheral blood levels of hydrocortisone. These observations suggest that chlorpromazine stimulates the release of ACTH from the adenohypophysis.

The effect of cortisone acetate on the secretion of adrenocorticotrophic hormone by the adenohypophysis

1. Cortisone acetate suspension, administered subcutaneously or orally to rats, caused no changes in adrenal ascorbic acid concentration. Intraperitoneal injections of cortisone acetate suspension caused profound adrenal ascorbic acid depletion, which was apparently due to a non-specific effect caused by the intraperitoneal administration of suspended matter.

2. Pretreatment of rats with large doses of cortisone acetate diminished, but did not prevent completely, the adrenal ascorbic acid depletion normally caused by unilateral adrenalectomy.