The Secretion of the Adrenal Cortex in the Sheep

Abstract

Adrenal venous blood was collected from six anaesthetized sheep, of which two had been previously hypophysectomized. The blood was extracted and analysed for adrenocortical steroids by paper chromatography. In each case the predominant secretory product found in the extracts was 17\g=a\-hydroxycorticosterone. Small amounts of corticosterone and a substance tentatively identified as 11\g=b\-hydroxyandrost-4-ene-3,17-dione were also found in all the extracts. Only traces of other reducing steroids or \g=a\\g=b\-unsaturated ketosteroids were found: their irregular appearance makes it likely that they were artifacts. It seems unlikely that the secretion of the adrenal cortex in vivo is as complex as the mixture of products released by the perfused beef adrenals in the experiments of Hechter, Zaffaroni, Jacobsen, Levy, Jeanloz, Schenker & Pincus [1951].The reported actions of cortical steroids, or whole adrenal extracts, when injected into mammals or added to isolated tissues have become so numerous that it has become essential to find out by direct experiment what the adrenal cortex actually secretes into the blood in various conditions. In the absence of direct knowledge of the nature of the cortical secretion, various theories of adrenocortical function have been proposed from time to time [e.g. Sayers, 1950], but recent work has cast considerable doubt upon them. All such theories postulate that the adrenal cortex secretes one or more steroid substances at particular rates in various physiological conditions, and it is necessary to find out whether this is the case or not. This paper describes experiments on six sheep in which adrenal venous blood was collected and analysed by paper chromatography [Bush, 1953] in order to determine the rate and type of secretion in this species. METHODS Experimental techniqueFive adult ewes and one wether of 50-70 kg were used (two Suffolks, two crossbreds, one Hampshire, and one Romney Marsh). One ewe (no. 4) and one wether (no. 6) had been hypophysectomized 2 days and 11 months respectively before the experi¬ ments by a technique described elsewhere [Ferguson, 1953]. In the ewe serial sections of the pituitary fossa showed one fragment of coagulated pituitary tissue adhering to the walls of the fossa which had been cauterized with diathermy after removal of most of the pituitary gland. No viable tissue could be found in the sections.In serial sections of the pituitary fossa of the wether (no. 6) no pituitary tissue could be found. The depression of wool-growth observed in this animal was further evidence of complete hypophysectomy [Ferguson, 1951].

The suppression of cortisol secretion by steroids, and response to corticotrophin in sheep with adrenal transplants

“…plasma range. The method is relatively specific for J4--3-keto-1 1 -hydroxy steroids so that cortisol, which is the major glucocorticoid secreted by the sheep's adrenal (Bush & Ferguson, 1953;McDonald & Reich, 1959), makes by far the largest contribution to fluorescence. The cortisol secretion rate was calculated from the concentration (mean of duplicates) and adrenal plasma flow per minute.…”

“…The relatively large blood volume of the sheep allows the collection of considerable quantities of adrenal venous blood for corticosteroid analysis without harming the animal. Further, sheep have a high and fairly constant cortisol: corticosterone secretion ratio (Bush & Ferguson, 1953;McDonald & Reich, 1959) which facilitates measurement of cortisol secretion. These factors permit not only the frequent measurement of cortisol secretion in the same conscious sheep but also study of the time sequence of the adrenal's response to excitatory or inhibitory stimuli.…”

The Effect of Aldosterone, Cortisol, and Corticosterone Upon the Sodium and Potassium Content of Sheep's Parotid Saliva*

“…Cortisol (6), corticosterone (6), and aldosterone (7-9) have been identified in sheep adrenal venous blood. In order to obtain a basis for evaluating the contribution of each of these components of the adrenal secretion to the fall in parotid salivary Na/K ratio observed during different physiological states, the effects of these steroids upon salivary Na and K were studied in a series of experiments in normal and adrenalectomized sheep.…”

Steroid production by incubated mouse adrenals

“…In the camel, cortisol and corticosterone are the main steroids produced by the adrenal cortex (104); a compound with the mobility of 18-hydroxy-11-deoxycorticosterone was also isolated from camel adrenals. Cortisol has been reported to be the main cortical hormone of sheep, but small amounts of corticosterone have also been detected (105,106). This was also the case in foetal sheep near term (107), indicating that the foetal adrenal is active, at least near term.…”