The contribution of the adrenal gland to the total amount of progesterone produced in the female rat.

1. The amount of progesterone contained in both adrenal glands of a rat was similar to or larger than the amount of progesterone in the ovaries of the same rat. This was found in unstressed rats, in stressed rats and also in pregnant rats.2. After ether anaesthesia and exsanguination the adrenal progesterone content was increased by 75%; the ovarian progesterone content remained unchanged.3. In contrast, prolonged operative stress resulted in a rise in the ovarian content of progesterone and 20-dihydroprogesterone whereas the adrenal progesterone content of these rats was lower than that of unstressed rats.4. The rate at which progesterone was secreted by the adrenal glands of stressed rats was similar to the ovarian progesterone secretion rate. Rats which were kept under mild stress conditions before the experiment showed higher adrenal progesterone secretion rates.

Adrenal secretion rates and adrenal tissue concentrations of pregnenolone, progesterone, 11 beta OH-androstenedione and some other steroids in young pigs and dogs.

1. The rates were measured at which a number of different steroids were secreted by the adrenal gland of the eviscerated and nephrectomized young pig and dog.2. In addition to cortisol and corticosterone the following steroids were consistently found to be present in the adrenal venous blood: pregnenolone, progesterone, 11betaOH-progesterone, androstenedione, 11betaOH-androstenedione and adrenosterone.3. The sum of the latter steroids could amount to as much as 30% of the total steroid secretion.4. A severe deficit in the blood volume increased the secretion of pregnenolone and the 17-oxo steroids in the pig.5. alpha-ethyltryptamine failed to inhibit ACTH release if the animals were eviscerated and nephrectomized, or if they were anaesthetized with chloralose instead of pentobarbitone sodium.6. The same steroids as in the adrenal venous blood were found in extracts from the adrenal glands of a number of species.7. The amount of individual steroids present in the adrenal gland of the stressed pig and dog was compared with the rate at which each had been secreted immediately before the excision of the gland.8. There was a positive correlation between the adrenal concentrations and the secretion rates of cortisol, the major glucocorticoid secreted by the pig and the dog.9. In contrast, the rate at which pregnenolone was secreted did not show a consistent relationship to its concentration in the gland.10. A storage mechanism for pregnenolone in the adrenal cortex is proposed.

Quantitative estimation of 17alpha-hydroxypregn-4-ene-3,20-dione (17alphaOH-progesterone) in adrenal venous blood and adrenal glands.

1. A method is described for the accurate estimation of small quantities of 17alpha-hydroxypregn-4-ene-3,20-dione (17alphaOH-progesterone) in blood and adrenal glands.2. The dog adrenal was found to secrete 17alphaOH-progesterone under conditions of operative stress at a rate of 5-10 mug/g tissue/hr. This is similar to the secretion rate of aldosterone.3. The secretion of 17alphaOH-progesterone was decreased after hypophysectomy and increased in response to adrenocorticotrophic hormone (ACTH).4. The adrenal gland of the dog, the monkey and the guinea-pig was found to contain between 0.6 and 6 mug of 17alphaOH-progesterone/g tissue. The concentration was usually somewhat smaller than that of pregnenolone or progesterone and between 1 and 20% of the concentrations of the glucocorticoids.5. A comparison of adrenal steroid contents and secretion rates under conditions of stress indicates a rate of synthesis in the order of 30-40 n-moles of 17alphaOH-progesterone/g adrenal tissue/min.

The effect of stress on the concentration of 3beta-hydroxypregn-5-en-20-one (pregnenolone) and pregn-4-ene-3,20-dione (progesterone) in the adrenal gland of the rat.

1. Pregnenolone and progesterone were estimated in extracts from adrenal glands of rats by gas-liquid chromatography.2. In unstressed rats their concentrations were found to be smaller than that of corticosterone.3. Acute stress caused an increase in the concentrations of these steroids which paralleled that of corticosterone.

Evidence for the presence of 16 alpha-hydroxypregn-4-ene-3,20-dione in adrenal venous blood of young pigs.

1. Evidence was obtained for the presence of 16alpha-hydroxypregn-4-ene-3,20-dione in each adrenal venous blood sample collected from eight young pigs under conditions of operative stress.2. The chemical identity of this steroid was tested on mug amounts by paper and gas chromatographic methods before and after the formation of derivatives.