Thread: quick read guys...
08-01-2005, 12:51 PM #1
quick read guys...
GHRH and sleep.
Obal F Jr, Krueger JM.
Department of Physiology, A. Szent-Gyorgyi Medical Center, University of Szeged, 6720, Szeged, Hungary. email@example.com
A significant portion of the total daily growth hormone (GH) secretion is associated with deep non-REM sleep (NREMS). GH secretion is stimulated by the hypothalamic neurohormone, GH-releasing hormone (GHRH). Exogenous GHRH promotes NREMS in various species. Suppression of endogenous GHRH (competitive antagonist, antibodies, somatostatinergic stimulation, high doses of GH or insulin -like growth factor) results in simultaneous inhibition of NREMS. Mutant and transgenic animals with a defect in GHRHergic activity display permanently reduced NREMS which cannot be reversed by means of GH supplementation. GHRH contents and mRNA levels in the hypothalamus correlate with sleep-wake activity during the diurnal cycle and sleep deprivation and recovery sleep. Stimulation of NREMS by GHRH is a hypothalamic action. GABAergic neurons in the anterior hypothalamus/preoptic region are candidates for mediating promotion of NREMS by GHRH. In contrast to NREMS, stimulation of REMS by GHRH is mediated by GH. Simultaneous stimulation of NREMS and GH secretion by GHRH may promote adjustment of tissue anabolism to sleep.
Systemic growth hormone does not affect human sleep.
Kern W, Halder R, al-Reda S, Spath-Schwalbe E, Fehm HL, Born J.
Department of Clinical Neuroendocrinology, University of Leubeck, Germany.
Subsequent to sleep onset, GH concentrations increase markedly, suggesting a stimulatory influence of sleep on GH secretion. However, results have been inconsistent as to whether GH conversely exerts a significant influence on sleep. Hence, the effects of exogenous administration of GH and of GH secretion stimulated by GH-releasing hormone (GHRH) on sleep were reexamined in 3 experiments in healthy male volunteers. In Exp I, 12 men participated on 3 experimental nights, receiving a constant iv infusion of 5 IU GH (between 2100-0700 h), an im bolus injection of 5 IU GH at 2100 h, and placebo. In Exp II, the effects of a short iv infusion of a high dose of 48 IU GH (between 2345-2315 h) on sleep were evaluated in 3 men. In Exp III, the effects of continuous infusion of 30 micrograms/h GHRH (between 2200-0700 h) on sleep were compared to the placebo condition in 10 men. Experiments were double blind, within-subject, cross-over comparisons and included an adaptation night before experimental nights. On all nights, the subjects went to bed at 2300 h and were awakened at 0700 h. Administration of GH elevated plasma GH and somatomedin-C levels throughout the night (P < 0.005). Neither im administration of 5 IU GH nor iv administration of 5 and 48 IU GH had any effect on the total sleep time or the time spent in different sleep stages during the whole night or in the first and second halves of sleep time. Infusion of GHRH increased nocturnal GH secretion (P < 0.005), but the episodic pattern of GH secretion was maintained. However, sleep remained unchanged during GHRH infusion. From these results we conclude that in healthy man, systemic GH has no physiological role for sleep regulation.
Different effects of short- and long-term recombinant hGH administration on ghrelin and adiponectin levels in GH-deficient adults.
Giavoli C, Cappiello V, Corbetta S, Ronchi CL, Morpurgo PS, Ferrante E, Beck-Peccoz P, Spada A.
Institute of Endocrine Sciences, University of Milan, Ospedale Maggiore IRCCS, Milan, Italy.
OBJECTIVE: To evaluate circulating levels of ghrelin and adiponectin (ApN) in GH-deficient (GHD) adults before and after short- and long-term recombinant human GH (rhGH) administration. PATIENTS AND METHODS: Twenty-three patients were studied. Seventeen subjects (Group A, 12 men, five women) were evaluated at baseline and after 1 year rhGH therapy (dose mean +/- SD: 0.3 +/- 0.1 mg/day) with the assessment of serum IGF-I, ghrelin, ApN, leptin, insulin and glucose levels, percentage of body fat (BF%), HOMA-IR and QUICKI. Seventeen age-, sex- and body mass index (BMI)-matched healthy subjects were recruited for comparisons. Six patients (Group B, three men, three women) underwent IGF-I generation test (rhGH 0.025 mg/kg/day for 7 days), blood sampled at baseline and on day 8 for determination of IGF-I, ghrelin and ApN levels. RESULTS: Group A: at baseline GHD patients showed low IGF-I levels and BF% significantly higher than controls (31.4 +/- 2.5 vs. 26.4 +/- 1.3, P < 0.05). Glucose, insulin, leptin, tryglicerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels, as well as HOMA-IR and QUICKI values were similar in the two series, while total cholesterol levels were higher in GHD. In GHD, ghrelin levels were significantly lower than in controls (193.9 +/- 27.1 vs. 298.1 +/- 32.5 pmol/l, respectively, P = 0.02), while ApN levels were similar (10.2 +/- 1.1 and 9 +/- 1 mg/l, respectively, P = ns). After 1 year of rhGH therapy, BF%, BMI, serum total and LDL cholesterol significantly decreased, serum leptin levels showed a trend to decrease, while HOMA-IR and QUICKI did not change. Ghrelin and ApN levels significantly increased from 193.9 +/- 27.1 to 232.4 +/- 26.3 pmol/l (P < 0.01) and from 8.6 +/- 0.8 to 10.3 +/- 1.1 mg/l (P < 0.05), respectively. In group B, the expected increase in IGF-I levels was associated with a significant decrease in ghrelin levels, while ApN did not change. CONCLUSION: GHD patients showed serum ghrelin lower than controls, probably due to the higher BF%. No difference in ApN was observed. Ghrelin and ApN increments induced by long-term treatment may be related to the significant BMI and BF% reduction that is the predominant metabolic effect of rhGH therapy. Conversely, the decrease in ghrelin levels observed after short-term rhGH administration may be consistent with an inhibitory feedback of GH and/or IGF-I on ghrelin release.
08-01-2005, 06:27 PM #2New Member
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- Jul 2005
new for me
08-02-2005, 03:37 AM #3Associate Member
- Join Date
- Jan 2005
but NOT a quick read.
08-02-2005, 10:12 AM #4Female Member
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LOL I was thinking the same thing LOL
Not a quick read!
08-02-2005, 10:35 AM #5
hey atleast you read ... no? ....lol
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