A possible involvement of VIP in feeding-induced secretion of ACTH and corticosterone in the rat.
For decades it has been known that brain/gut peptides are released during the ingestion of a meal. Although a multitude of actions have been attributed to these peptides acting in the brain, including the release or inhibition of a variety of pituitary hormones, the actual physiological roles of these substances in the brain have not been confirmed. For the first time, we have demonstrated that feeding-induced hypothalamic-pituitary-adrenal (HPA) secretion may involve the brain/gut peptide, vasoactive intestinal peptide (VIP), acting in the paraventricular nucleus (PVN) of the hypothalamus. The effects of 24 h fasting and refeeding on the release of plasma ACTH and CORT secretion in male rats were investigated. Blood samples were collected 5 min prior to PVN administration of saline or VIP antagonist, [Lsy, Pro, Arg, Tyr]-VIP and 30 min after refeeding. Plasma ACTH and CORT concentrations were significantly increased by 43 and 485%, respectively, by 30 min ingestion of food. Pretreatment with the VIP antagonist (0.75 and 1.5 nmol/rat) significantly reduced the food-induced ACTH response by 69 and 76% and the CORT response by 58 and 65%, respectively. There were no significant differences in food-intake among groups. These results suggest that one potential role of hypothalamic VIP may involve activation of hypothalamic-releasing factors to regulate ACTH and CORT levels during or after a meal.
Alexander
L D
LD
Division of Hypertension, University Hospital of Cleveland, Case Western Reserve University School of Medicine, OH 44106-4982, USA.
Evans
K
K
Sander
L D
LD
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D002406:Catheterization, Peripheral; D003345:Corticosterone / Q000097:blood*; D004435:Eating / Q000502:physiology*; D007031:Hypothalamus; D008297:Male; D008845:Microinjections; D051381:Rats; D017207:Rats, Sprague-Dawley; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology / Q000502:physiology*
D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone