Evaluation of the role of melanocortin 3 and 4 receptors in leptin-stimulated and spontaneous growth hormone secretion in rats - PubMed (original) (raw)
Evaluation of the role of melanocortin 3 and 4 receptors in leptin-stimulated and spontaneous growth hormone secretion in rats
Hajime Watanobe et al. Neuroendocrinology. 2003 Dec.
Abstract
It has been reported that the melanocortin 4-receptor (MC4-R) may act downstream of leptin to mediate its effects on food intake and several neuroendocrine functions (the reproductive system, the hypothalamo-pituitary-thyroid axis, and prolactin secretion). However, no previous study examined whether MC4-R mediates leptin stimulatory actions on growth hormone (GH) secretion, or whether MC4-R signaling is involved in spontaneous pulsatile GH release in fed rats. Therefore in this study we examined the involvement of both MC3-R and MC4-R (the predominant MC-R subtypes expressed in the brain) in these two aspects of GH secretion in freely-moving male rats. In both fed and 3-day fasted rats, plasma GH levels were determined every 15 min over 5 h after single intracerebroventricular injections of the following substances or vehicle. Fasting diminished and leptin (0.3 nmol) reinstated the GH pulse amplitude without affecting the pulse frequency. Neither HS014 (1.0 nmol, a selective MC4-R antagonist) nor agouti-related peptide (1.0 nmol, a non-selective MC3/4-R antagonist) was effective in altering leptin-stimulated or spontaneous GH secretion. In addition, neither melanotan-II (1.0 nmol, a non-selective MC3/4-R agonist) nor gamma(1)-melanocyte-stimulating hormone (10 nmol, a selective MC3-R agonist) affected significantly GH release in fasted rats. We have previously demonstrated that stimulation or blockade of MC4-R, achieved by the same drug dosage as in this study, significantly affect luteinizing hormone and prolactin secretion in rats. The present results thus suggest that neither MC4-R nor MC3-R is involved in leptin-stimulated or spontaneous GH secretion, or at least that the level of MC4-R involvement in GH secretion is much lower than that in luteinizing hormone and prolactin release regulation.
Copyright 2003 S. Karger AG, Basel
Similar articles
- The melanocortin 4 receptor mediates leptin stimulation of luteinizing hormone and prolactin surges in steroid-primed ovariectomized rats.
Watanobe H, Schiöth HB, Wikberg JE, Suda T. Watanobe H, et al. Biochem Biophys Res Commun. 1999 Apr 21;257(3):860-4. doi: 10.1006/bbrc.1999.0547. Biochem Biophys Res Commun. 1999. PMID: 10208874 - The role of melanocortin-3 and -4 receptor in regulating appetite, energy homeostasis and neuroendocrine function in the pig.
Barb CR, Robertson AS, Barrett JB, Kraeling RR, Houseknecht KL. Barb CR, et al. J Endocrinol. 2004 Apr;181(1):39-52. doi: 10.1677/joe.0.1810039. J Endocrinol. 2004. PMID: 15072565 - Pivotal roles of alpha-melanocyte-stimulating hormone and the melanocortin 4 receptor in leptin stimulation of prolactin secretion in rats.
Watanobe H, Schiöth HB, Izumi J. Watanobe H, et al. J Neurochem. 2003 Apr;85(2):338-47. doi: 10.1046/j.1471-4159.2003.01683.x. J Neurochem. 2003. PMID: 12675910 - [Psychiatric disorders and neural mechanisms underlying energy intake and expenditure: a review].
Kishi T, Horiguchi J. Kishi T, et al. Nihon Shinkei Seishin Yakurigaku Zasshi. 2003 Oct;23(5):197-203. Nihon Shinkei Seishin Yakurigaku Zasshi. 2003. PMID: 14653225 Review. Japanese. - Melanocortin-4 receptor: a novel signalling pathway involved in body weight regulation.
Fisher SL, Yagaloff KA, Burn P. Fisher SL, et al. Int J Obes Relat Metab Disord. 1999 Feb;23 Suppl 1:54-8. doi: 10.1038/sj.ijo.0800796. Int J Obes Relat Metab Disord. 1999. PMID: 10193863 Review.
Cited by
- Effects of leptin and melanocortin signaling interactions on pubertal development and reproduction.
Israel DD, Sheffer-Babila S, de Luca C, Jo YH, Liu SM, Xia Q, Spergel DJ, Dun SL, Dun NJ, Chua SC Jr. Israel DD, et al. Endocrinology. 2012 May;153(5):2408-19. doi: 10.1210/en.2011-1822. Epub 2012 Mar 9. Endocrinology. 2012. PMID: 22408174 Free PMC article. - The role of the central melanocortin system in the regulation of food intake and energy homeostasis: lessons from mouse models.
Ellacott KL, Cone RD. Ellacott KL, et al. Philos Trans R Soc Lond B Biol Sci. 2006 Jul 29;361(1471):1265-74. doi: 10.1098/rstb.2006.1861. Philos Trans R Soc Lond B Biol Sci. 2006. PMID: 16815803 Free PMC article. Review.
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources