DISSOCIATION OF ADRENAL ASCORBIC ACID AND CORTICOSTERONE RESPONSES TO STRESS IN RATS WITH HYPOTHALAMIC LESIONS1

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Abstract
A dichotomy has been observed between the adrenal ascorbic acid and corticosterone response to surgical stress in male rats with bilateral electrolytic lesions placed in the hypothalamus. Thus lesions in the posterior and midcentral portions of the hypothalamus specifically inhibited corticosterone release without altering adrenal ascorbic acid response or the weights of target organs dependent upon the normal production of pituitary hormones. Similarly, lesions in the basal tuberal region inhibited adrenal ascorbic acid depletion without affecting corticosterone release in response to stress. However, the latter lesions (with involved the median eminence) were not adrenal specific inasmuch as atrophy to the testes, seminal vesicles and prostate was also noted. Gross damage to the median eminence, basal tuberal region and portal systems blocked both adrenal responses and frequently resulted in atrophy to the thyroid and adrenal glands as well as of the sexual target organs. Water intake following hypothalamic damage was not correlated with adrenal responsiveness. Possible explanations are discussed for the ability of the adrenal to exhibit discriminatory responses to stress following hypothalamic lesions.