22 - Orexins, a novel family of hypothalamic neuropeptides, Pu, S.

22 Orexins a - • Alteration in nutritional status have profound effects on reproduction • Central mechanisms coordinating energy homeostasis

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Article #19 – Orexins, a Novel Family of Hypothalamic Neuropeptides, modulate Pituitary Luteinizing Hormone Secretion in an Ovarian Steroid-Dependent Manner NPY, galanin and opiods link the neural processes that regulate reproduction and energy intake produced in the medial basal hypothalamus stimulate appetite and affect secretion of pituitary gonadotropin, leutenizing hormone (LH), by modulating release o fhypothalamic leteinizing hormone releasing hormone (LHRH) orexin producing neurons are localized in the lateral hypothalamus and perifornical area innervate the posterior hypothalamus orexins stimulate feeding in a dose related fashion Orexin A more effective than orexin B at stimulating feeding orexin upregulation is in response to energy depletion orexins may play a key role in hypo. regulation of reproduction
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Unformatted text preview: • Alteration in nutritional status have profound effects on reproduction • Central mechanisms coordinating energy homeostasis and reproduction reside in hypothalamus • NPY, galanin and opioids stimulate appetite and affect secretion of pituitary gonadotropin, luteinizing hormone (LH) by modulating release of hypothalamic LHRH • Imbalanced energy intake = depressed pituitary-gonadal function • In steroid primed rates, Orexin A and B stimulated LH (but A more so than B) • In unprimed rats, both orexins inhibited LH secretion • orexins exert a modulatory influence on pituatory LH secrection • Orexins may act as an excitatory signal in hypothalamic control of LH secretion in intact female rats • NPY may be one of mediators of effects of orexins • Mating stimulates and fasting inhibits gonadotropin secretion...
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This note was uploaded on 03/18/2012 for the course BIO 3UU3 taught by Professor Dr.rollo during the Spring '12 term at McMaster University.

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