[The activity of the enkephalinergic systems of the brain and hypophysis in experimental hypocorticism]

Abstract

Changes in activity of basic components of enkephalinergic system, leu-enkephalin contents, activity of enkephalin-hydrolysing enzymes (enkephalinases A and B, enkephalin aminopeptidases) and 3H-leu-enkephalin specific binding to opioid receptor in rat anterior and mediobasal hypothalamus, striatum, medulla oblongata and adenohypophysis have been analysed on experimental models of hypocorticoidism. No changes in brain and pituitary body leu-enkephalin contents following unilateral hypocorticoidism. No changes in brain and pituitary body leu-enkephalin contents following unilateral adrenalectomy were shown. Bilateral adrenalectomy resulted in two-phase character of neuropeptide level: a decrease of leu-enkephalin contents in hypothalamus, striatum and adenohypophysis on the 7th day and its increase to the normal level on the 10th day after the operation were revealed. A decrease of leu-enkephalin contents in rat brain on the 7th day following adrenalectomy occurred simultaneously with a decrease in enkephalin aminopeptidase activity and specific binding of labeled leu-enkephalin testifying to strengthening of enkephalin release form neurosecretory granules of brain structures following adrenalectomy. Important changes in leu-enkephalin contents, reception and inactive processes on the level of adenohypophysis and on the level of hypothalamus, striatum and medulla oblongata were detected by cortisol and ACTH administration in adrenalectomised animals.