Modification of stress-induced prolactin release by dexamethasone or adrenalectomy

A study was conducted to determine the influence of conditions known to alter ACTH secretion on prolactin release by the pituitary. Dexamethasone or 0.9% NaCl was injected subcutaneously into intact male rats 4 hr before a 2-min ether stress. Other rats were submitted to the ether stress 2 weeks following adrenalectomy. Five min following exposure to the ether stress, the rats were decapitated and trunk blood was collected. Dexamethasone (31, 125 or 500 mug/kg) blocked the stress-induced prolactin release in a dosage dependent manner with the highest dose decreasing plasma prolactin to levels similar to those observed in rats not exposed to the ether stress. Conversely, adrenalectomy was found to potentiate prolactin release due to ether stress. The results indicate that the adrenal may play a regulatory role in stress-induced prolactin release. The are also consistent with the suggestion that a common pathway or mechanism may be involved in pituitary release.