Sleep loss alters hypothalamic growth hormone-releasing hormone receptors in rats.
Previous experiments suggest that sleep deprivation (SD) is associated with growth hormone-releasing hormone (GHRH) release and that GHRH promotes sleep via intrahypothalamic sites of action. Binding of [His(1), (125)I-Tyr(10), Nle(27)]hGHRH(1-32) amide and GHRH receptor (GHRH-R) mRNA levels were determined in the hypothalamus and pituitary of rats subjected to 8 h of SD and of undisturbed control rats. The characteristics of the hypothalamic GHRH binding sites differed from those of the pituitary. High affinity GHRH binding and GHRH-R mRNA levels decreased by 50% in the hypothalamus of SD rats, whereas there were no alterations in the pituitary. The results demonstrate that GHRH-Rs exist in the hypothalamus and they respond differently to SD than the GHRH-Rs in the pituitary. The SD-induced changes are explained by down-regulation of the hypothalamic GHRH-Rs induced by GHRH release during and after SD.
Gardi
J
J
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, P.O. Box 646520, Pullman, WA, USA.
Taishi
P
P
Speth
R
R
Obal
F
F
Krueger
J M
JM
D000818:Animals; D015870:Gene Expression / Q000502:physiology; D013007:Growth Hormone-Releasing Hormone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D010913:Pituitary-Adrenal System / Q000378:metabolism* / Q000503:physiopathology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism*; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics / Q000378:metabolism*; D012892:Sleep Deprivation / Q000378:metabolism* / Q000503:physiopathology
D012333:RNA, Messenger; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D013007:Growth Hormone-Releasing Hormone; C066200:somatotropin-releasing hormone (1-32)amide, His(1),Nle(27)-; C048250:somatotropin releasing hormone receptor