Possible Interaction: Neuropeptide Y and Adrenocorticotropic Hormone

“Recently, we have found in young normal male controls after repetitive administration of NPY a shortened sleep latency and a decrease of time awake and, in the second half of the night, EEG delta-power; cortisol and ACTH levels were blunted.”

“A series of analogues of NPY that have a greatly reduced affinity for the Y1 [human pancreatic polypeptide (human PP), NPY(3-36)], the Y2 ([Pro34]NPY, human PP), the Y3 (peptide YY), and the Y6 (human PP) receptor, all markedly stimulated ACTH release.”

“Release of several anterior pituitary hormones, such as corticotropin (ACTH), growth hormone and thyroid-stimulating hormone, is also modulated by NPY and it remains to be seen whether the observed metabolic effects are mediated by the autonomic nervous system or via alterations in hormonal status.”

“We propose that intra-adrenal NPY is responsible for blunting adrenocortical responses to ACTH stimulation in the MR strain.”

“ NPY significantly increased ACTH , corticosterone and oxytocin secretion in the virgins but had no such effect on ACTH or oxytocin in the pregnant rats; the corticosterone response to NPY was markedly attenuated in pregnant rats.”

“Intraperitoneally administered NPY (27 nmol /100g body wt) raised ACTH plasma levels (from 5.23+/-0.06 pg/ml in carrier injected specimens to 6.83+/-0.01 pg/ml, 24 h after the injection).”

“Concurrently, we found that both acute and chronic infusion of neuropeptide Y induced a significant reduction in corticotropin-releasing factor in the hypothalamus as well as a significant decrease in alpha-melanocyte-stimulating hormone and corticotropin in the neurointermediate and anterior lobes, respectively.”

“However, in the presence of physiological concentrations of ACTH, which are submaximal for the stimulation of aldosterone secretion, NPY (10(-6) mol/l) significantly enhanced the secretion rate of aldosterone by rat zona glomerulosa cells in response to ACTH.”

“The effect of NPY appears to be biphasic, however, as NPY significantly attenuated the steroidogenic response to supramaximal ACTH concentrations: in rat zona glomerulosa cells the aldosterone response to 10(-8) mol ACTH/l was significantly inhibited by NPY.”

“ Neuropeptide Y (NPY) has a stimulatory effect on adrenocorticotropin (ACTH) and corticotropin-releasing factor (CRF) release.”

“The administration of 0.01, 0.1 and 1 nmol of NPY into the lateral ventricle dose-dependently Increased the plasma ACTH levels, as well as the levels of proopiomelanocortin mRNA in the anterior pituitary.”

“The present findings that NPY evokes ACTH secretion and potentiates the effectiveness of CRF as a secretagogue, together with high concentrations of NPY in the hypothalamus and pituitary portal blood, suggest the NPY is involved in the multihormonal control of ACTH release.”

“dose of NPY produced as great an ACTH and cortisol response as did equimolar ovine corticotropin releasing factor (CRF).”