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Hypothalamic regulation of luteinizing hormone. reproduction physiologyTo assess if the hypothalamic median eminence (ME) is a neuroendocrine control site where final hypophysiotropic release leading to the preovulatory surge of Luteinizing Hormone (LH). an obligatory event for reproduction to occur. might be ultimately regulated. We have used two animal models for these studies: hens. showing daily LH preovulatory surges for 15-25 days and ewes. showing an LH preovulatory surge at the end of each follicular phase in a 16-day estrous cycle. In our studies. we have concentrated in assessing the hypothalamic control of LHRH by three of its ME putative inputs: ß-endorphin (ßEND). dopamine (DA). and neuropeptide Y (NPY). Through our immunocytochemical studies we mapped the hypothalamic distribution of LHRH and these three ME putative inputs. in hens and ewes. On the other hand. in our release studies. we used in vitro incubations of ME tissue and push-pull cannula (PPC) sampling of in vivo neuropeptide release from discrete areas of the ME. In addition to our release studies. we assessed the possibility that enzymatic degradation of LHRH in the ME might be a regulated event of some physiological significance. Furthermore. we recently determined steady-state levels of mRNA and expression of c-fos antigens. in some of these putative inputs to ME-LHRH neuronal terminals. In addition. we have developed an extremely sensitive capillary electrophoresis-based assay. that uses fluorescence microscopy detection of derivatized samples. for the determination of multiple neuropeptides in ME-PPC perfusate samples. Selected PublicationsChen CP. Kuhn P. Advis JP. Sarkar DK. (2006) Prenatal ethanol exposure alters the expression of period genes governing the circadian function of beta-endorphin neurons in the hypothalamus. J Neurochem. 97(4):1026-33. Chen CP. Kuhn P. Advis JP. Sarkar DK. (2006) Prenatal ethanol exposure alters the expression of period genes governing the circadian function of beta-endorphin neurons in the hypothalamus. J Neurochem. Apr 5; [Epub ahead of print] Dokur M. Chen CP. Advis JP. Sarkar DK. (2005) Beta-endorphin modulation of interferon-gamma. perforin and granzyme B levels in splenic NK cells: effects of ethanol. J Neuroimmunol. 166(1-2):29-38. Dokur M. Boyadjieva NI. Advis JP. Sarkar DK. (2004) Modulation of hypothalamic beta-endorphin-regulated expression of natural killer cell cytolytic activity regulatory factors by ethanol in male Fischer-344 rats. Alcohol Clin Exp Res. 28(8):1180-6. Cifuentes M. Advis JP. Shapses SA. (2004) Estrogen prevents the reduction in fractional calcium absorption due to energy restriction in mature rats. J Nutr. 134(8):1929-34. Chen CP. Kuhn P. Advis JP. Sarkar DK. (2004) Chronic ethanol consumption impairs the circadian rhythm of pro-opiomelanocortin and period genes mRNA expression in the hypothalamus of the male rat. J Neurochem. 88(6):1547-54. Boyadjieva NI. Dokur M. Advis JP. Meadows GG. Sarkar DK. (2002) Beta-endorphin modulation of lymphocyte proliferation: effects of ethanol. Alcohol Clin Exp Res. 26(11):1719-27. Boyadjieva N. Advis JP. and Sarkar DK (2000). Ethanol reduces the effect of hypothalamic ß-endorphin on natural killer cell activity. Anual meeting of the Endocrine Society. Toronto. Canada. Advis JP. Klein J and Sarkar DK (2000). Effects of ethanol on secretion of hypothalamic neuropeptides regulating preovulatory LH release in sheep. Annual meeting of the Research Society on Alcoholism (RSA). Buntin JD. Advis JP. Ottinger MA. Lea RW and Sharp PJ (1999). An analysis of physiological mechanisms underlying the antigonadotropic action of intracranial prolactin in Ring Doves. General and Comparative Endocrinology 114. 97-107. Park S. Hung W-L. Guzman N. and Advis JP (1996). Determination of neuropeptides by capillary electrophoresis. In Methods in Molecular Biology. Vol 73: Neuropeptide Protocols. Chapter 11. Edited by B Irvine and C Williams. Humana Press Inc. p101-111. |
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