AJP - Endocrinology and Metabolism, Vol 270, Issue 2 E230-E237, Copyright © 1996 by American Physiological Society

ARTICLES

Effects of systemic GHRH on sleep in intact and hypophysectomized rats

F. Obal Jr, R. Floyd, L. Kapas, B. Bodosi and J. M. Krueger
Department of Physiology, A. Szent-Gyorgyi Medical University, Szeged, Hungary.

The role of pituitary growth hormone (GH) in the mediation of enhanced sleep elicited by GH-releasing hormone (GHRH) was studied in the rat. Intact and hypophysectomized (HYPOX) rats received systemic injections of GHRH or physiological saline. GHRH (0.5, 5.0, or 50 micrograms/kg in the intact rats and 0.5 or 50 micrograms/kg in HYPOX rats) was injected 6 h after light onset (P.M. injection) or just before light onset (A.M. injection, 0.5 microgram/kg in both A.M. groups). Sleep-wake activity and brain cortical temperature were recorded for 23 h (12 h light + 11 h dark). A.M. injection of GHRH did not alter sleep in normal or HYPOX rats. Each dose of P.M. GHRH increased rapid-eye-movement sleep (REMS) during 6 h postinjection in the intact rats. Hypophysectomy abolished the REMS-promoting activity of GHRH. P.M. injection of 0.5 microgram/kg GHRH increased non-REM sleep (NREMS) and enhanced electroencephalogram slow-wave activity during NREMS in both the intact and the HYPOX rats. The NREMS-promoting activity disappeared when the dose of GHRH was increased in the intact rats, whereas a tendency to enhanced NREMS was still observed after 50 micrograms/kg GHRH in the HYPOX rats. GHRH stimulated GH secretion dose dependently in the intact rats. A.M. injection of 0.5 microgram/kg GHRH tended to be less effective in stimulating GH release than the same dose administered P.M. The results confirm the time-of-day variations in the GHRH effects on sleep previously reported in human subjects. It is likely that pituitary GH is involved in the mediation of the REMS-promoting activity of GHRH but not in the NREMS-promoting activity of GHRH. Nevertheless, the results do not exclude the possibility that GH may modulate NREMS.

This article has been cited by other articles:

				E. Szentirmai, T. Yasuda, P. Taishi, M. Wang, L. Churchill, S. Bohnet, P. Magrath, B. Kacsoh, L. Jimenez, and J. M. Krueger Growth hormone-releasing hormone: cerebral cortical sleep-related EEG actions and expression Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R922 - R930. [Abstract] [Full Text] [PDF]

				P. Schussler, A. Yassouridis, M. Uhr, M. Kluge, J. Weikel, F. Holsboer, and A. Steiger Growth hormone-releasing hormone and corticotropin-releasing hormone enhance non-rapid-eye-movement sleep after sleep deprivation. Am J Physiol Endocrinol Metab, September 1, 2006; 291(3): E549 - E556. [Abstract] [Full Text] [PDF]

				F. Obal Jr., J. Alt, P. Taishi, J. Gardi, and J. M. Krueger Sleep in mice with nonfunctional growth hormone-releasing hormone receptors Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2003; 284(1): R131 - R139. [Abstract] [Full Text] [PDF]

				F. Obal Jr, J. Fang, P. Taishi, B. Kacsoh, J. Gardi, and J. M. Krueger Deficiency of Growth Hormone-Releasing Hormone Signaling Is Associated with Sleep Alterations in the Dwarf Rat J. Neurosci., April 15, 2001; 21(8): 2912 - 2918. [Abstract] [Full Text] [PDF]

				B. Bodosi, F. Obal Jr., J. Gardi, J. Komlodi, J. Fang, and J. M. Krueger An ether stressor increases REM sleep in rats: possible role of prolactin Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1590 - R1598. [Abstract] [Full Text] [PDF]

				K. Spiegel, R. Leproult, E. F. Colecchia, M. L'Hermite-Baleriaux, Z. Nie, G. Copinschi, and E. Van Cauter Adaptation of the 24-h growth hormone profile to a state of sleep debt Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2000; 279(3): R874 - R883. [Abstract] [Full Text] [PDF]

				L. Beranek, I. Hajdu, J. Gardi, P. Taishi, F. Obal Jr., and J. M. Krueger Central administration of the somatostatin analog octreotide induces captopril-insensitive sleep responses Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1999; 277(5): R1297 - R1304. [Abstract] [Full Text] [PDF]

				J. Gardi, F. Obal Jr., J. Fang, J. Zhang, and J. M. Krueger Diurnal variations and sleep deprivation-induced changes in rat hypothalamic GHRH and somatostatin contents Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1999; 277(5): R1339 - R1344. [Abstract] [Full Text] [PDF]

				J. Zhang, F. Obal Jr, T. Zheng, J. Fang, P. Taishi, and J. M. Krueger Intrapreoptic Microinjection of GHRH or Its Antagonist Alters Sleep in Rats J. Neurosci., March 15, 1999; 19(6): 2187 - 2194. [Abstract] [Full Text] [PDF]

				J. Zhang, Z. Chen, P. Taishi, F. Obal Jr., J. Fang, and J. M. Krueger Sleep deprivation increases rat hypothalamic growth hormone-releasing hormone mRNA Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1998; 275(6): R1755 - R1761. [Abstract] [Full Text] [PDF]

				J. M. Krueger, J. Fang, M. K. Hansen, J. Zhang, and F. Obal Jr. Humoral Regulation of Sleep Physiology, August 1, 1998; 13(4): 189 - 194. [Abstract] [Full Text] [PDF]

				R. Moreno-Reyes, M. Kerkhofs, M. L'Hermite-Baleriaux, M. O. Thorner, E. Van Cauter, and G. Copinschi Evidence against a role for the growth hormone-releasing peptide axis in human slow-wave sleep regulation Am J Physiol Endocrinol Metab, May 1, 1998; 274(5): E779 - E784. [Abstract] [Full Text] [PDF]

				L. Beranek, F. Obal Jr., P. Taishi, B. Bodosi, F. Laczi, and J. M. Krueger Changes in rat sleep after single and repeated injections of the long-acting somatostatin analog octreotide Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1997; 273(4): R1484 - R1491. [Abstract] [Full Text] [PDF]

				I. Hajdu, F. Obal Jr., J. Fang, J. M. Krueger, and C. D. Rollo Sleep of transgenic mice producing excess rat growth hormone Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2002; 282(1): R70 - R76. [Abstract] [Full Text] [PDF]