Abstract
It has previously been shown that the injection of pure adrenotrophic hormone into rats is followed by a rapid fall in adrenal ascorbic acid, a slower fall in adrenal cholesterol, and an increase in liver glycogen.1,2,3 It has been found (unpublished experiments) that exposure of rats to such conditions as cold, scalds, or hemorrhage is also followed by a depletion of adrenal cholesterol and ascorbic acid. However, since the above stresses are without any effect on the adrenal cholesterol and ascorbic acid of hypophysectomized rats, it is evident that a release of adrenotrophic hormone from the anterior pituitary is a preliminary and necessary step in the adrenal cortical response to an increased need for cortical hormone.
The factors, humeral or nervous, that are associated with stress and which lead to an increased secretion of adrenotrophic hormone are not known, but it would appear that one common denominator is an increased degree of activity of the sympathetic nervous system, with a consequent release of epinephrine. We have, therefore, investigated the effect of epinephrine on the cholesterol and ascorbic acid levels of normal and hypophysectomized rats.
Methods. Male rats about 200 g in weight of either Sprague-Dawley or Yale strain were used for this investigation. Non-fasted animals were hypophysectomized by the parapharyngeal approach under ether anesthesia. They were used on the third postoperative day after a fast of 18 hours, while food was withheld from normal rats 24 hours before the experiment.
A 4-hour course of injections was given subcutaneously to both groups. Every hour each animal received 0.02 mg/100 g of epinephrine in physiological saline. One hour following the last injection the rats were quickly anesthetized with nembutal. The adrenals were removed and weighed on a torsion balance.
Get full access to this article
View all access options for this article.