Neuropeptide Y and glucocorticoid secretion from guinea pig adrenal gland: An in vivo and in vitro study

  • Authors:
    • N. Venkat Appa Rao
    • Carlo Macchi
    • Cinzia Tortorella
    • M. Firoz Ahmad
    • Gastone G. Nussdorfer
  • View Affiliations

  • Published online on: September 1, 2007     https://doi.org/10.3892/ijmm.20.3.345
  • Pages: 345-349
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Abstract

The effects of neuropeptide Y (NPY) on adrenal glucocorticoid secretion are controversial, and we have investigated this issue in guinea pigs, where, like in humans and cows, the main glucocorticoid hormone is cortisol. In vivo experiments showed that prolonged NPY administration markedly lowered cortisol plasma concentration not only in normal guinea pigs, but also in animals whose hypothalamic-pituitary-adrenal axis and renin-angiotensin system had been pharmacologically interrupted by the simultaneous administration of dexamethasone and captopril. In vitro experiments ruled out the possibility that in vivo glucocorticoid anti-secretagogue action of NPY can ensue from a direct effect on the adrenal gland. In fact, NPY did not affect cortisol secretion from dispersed guinea pig inner adrenocortical cells. In contrast, NPY raised cortisol production from adrenal slices containing medullary tissue, and this effect was blocked by the β-adrenoceptor antagonist l-alprenolol. This finding, coupled with the demonstration that NPY enhanced catecholamine release from guinea pigadrenomedullary tissue, strongly suggests that NPY may stimulate glucocorticoid secretion in this species through an indirect mechanism involving catecholamines, that in a paracrine manner promote the secretion of inner adrenocortical cells. In light of these observations, the conclusion is drawn that the in vivo effects of NPY are mediated by mechanism(s) independent of either the suppression of the main adrenal agonists ACTH and angiotensin-II or the direct inhibition of adrenal secretion. The possibility merits an investigation into whether NPY enhances the production of peptides, which, like leptin, inhibit adrenal glucocorticoid secretion acting as circulating hormones.

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September 2007
Volume 20 Issue 3

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Rao NV, Macchi C, Tortorella C, Ahmad MF and Nussdorfer GG: Neuropeptide Y and glucocorticoid secretion from guinea pig adrenal gland: An in vivo and in vitro study. Int J Mol Med 20: 345-349, 2007
APA
Rao, N.V., Macchi, C., Tortorella, C., Ahmad, M.F., & Nussdorfer, G.G. (2007). Neuropeptide Y and glucocorticoid secretion from guinea pig adrenal gland: An in vivo and in vitro study. International Journal of Molecular Medicine, 20, 345-349. https://doi.org/10.3892/ijmm.20.3.345
MLA
Rao, N. V., Macchi, C., Tortorella, C., Ahmad, M. F., Nussdorfer, G. G."Neuropeptide Y and glucocorticoid secretion from guinea pig adrenal gland: An in vivo and in vitro study". International Journal of Molecular Medicine 20.3 (2007): 345-349.
Chicago
Rao, N. V., Macchi, C., Tortorella, C., Ahmad, M. F., Nussdorfer, G. G."Neuropeptide Y and glucocorticoid secretion from guinea pig adrenal gland: An in vivo and in vitro study". International Journal of Molecular Medicine 20, no. 3 (2007): 345-349. https://doi.org/10.3892/ijmm.20.3.345