A marked decrease of vasoactive intestinal peptide release in obese patients.
The presence of vasoactive intestinal peptide (VIP) in the hypothalamus, anterior pituitary, and hypophyseal portal blood strongly suggests that VIP might be involved in the regulation of pituitary hormone secretion. To elucidate the relationship between VIP and the adrenergic system and its role in the mechanism of disturbed prolactin (PRL) and growth hormone (GH) release in obesity, serum VIP, GH, and PRL concentrations in response to alpha 2-adrenergic receptor agonist-clonidine were measured. Serum VIP levels were dramatically lower in obese as compared with non-obese patients, whereas clonidine did not alter VIP and PRL concentrations in either obese or non-obese patients. However, the response of GH to clonidine injection was blunted in obese patients. These results demonstrate an inhibited release of VIP in obesity. Whether a marked decrease of VIP may play a role in the mechanism of a disturbed release of GH and PRL remains to be explained.
Baranowska
B
B
Neuroendocrinology Department, Medical Center of Postgraduate Education, Warsaw, Poland.
D000328:Adult; D003000:Clonidine; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D011388:Prolactin / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D011942:Receptors, Adrenergic, alpha; D014660:Vasoactive Intestinal Peptide; D011388:Prolactin; D013006:Growth Hormone; D003000:Clonidine