Infertility often results from disruption of menstrual cyclicity and/or ovulation: processes known to be driven by specific hypothalamic signals. By monitoring neurosecretions in either naturally ovulating or ovariectomized (OVX) rhesus macaques, we observed a 10-fold increase in gonadotropin-releasing hormone (GnRH) secretion during an estradiol- 17beta (E2)-induced luteinizing hormone (LH) surge. No less than 14 neurotransmitter/neuropeptide(s) are implicated in the regulation of GnRH secretion. Because adrenergic receptors are found on GnRH neurons, we initially focus on norepinephrine (NE) and neuropeptide Y (NPY), which are colocalized in noradrenergic cells and stimulate GnRH gene expression and secretion in E2-conditioned animals, including macaques.
Aim 1 a will resolve if the preovulatory rise in ovarian E2 stimulates NE and NPY secretion in conjunction with the E2-induced GnRH/LH surge.
Aim 1 b will decipher if blockade of either NE or NPY receptor activity by selective antagonists blocks the GnRH/LH surge. Continuous push-pull perfusion or microdialysis will be performed in the mediobasal hypothalamus (MBH) of both intact and OVX monkeys with or without treatment of prazosin (NE antagonist) and (Ac[3-(2,6 dichlorobenzyl)tyr(27,36)D-Thr(32)]NPY-(27- 36)amide (NPY antagonist). Changes in perfusate levels of NE, NPY and GnRH will be analyzed by high-performance liquid chromatography and radioimmunoassays, respectively.
Aim 2 addresses the morphometric and intracellular evidence of how E2 influences NPY/NE/GnRH secretion.
Aim 2 a will determine if estrogen receptors are localized in NE and/or NPY neurons, if NPY is produced in NE neurons, and if NE/NPY terminals synapse with hypothalamic GnRH neurons. Histological sections of the MBH and brainstem (i.e., locus coeruleus/lateral tegmentum) will be examined for the localization of neurons that express estrogen receptor mRNAs (by in situ hybridization) and NE (i.e., dopamine-beta-hydroxylase), NPY and GnRH (by immunocytochemistry).
Aim 2 b will quantitate E2-induced changes in NPY and NE (i.e., tyrosine hydroxylase) mRNA contents in identified loci of brainstem and hypothalamus by ribonuclease protection assay.
Aims 3 and 4 examine how synaptic NE secretion interacts with other putative neuromodulators to regulate GnRH release.
Aim 3 a will determine if blockade of NE transporter activity (presynaptic NE reuptake) by the antidepressant, desipramine, acutely stimulates NE, hence GnRH, release.
Aim 3 b will show that continuous desipramine infusion suppresses NE/GnRH secretion, and establish if GnRH pulses can be reinitiated by pulses of NE or neuroexcitatory amino acids (i.e., N-methyl-D,L-aspartate). Microdialysis cannulae implanted in the MBH of OVX monkeys will be used for acute (3a) or continuous (3b) desipramine treatment, pulsatile NE or N-methyl-D,L-aspartate infusion (3b) and microdialysate collection for NE and GnRH measurements (3a,b).
Aim 4 a will examine by in situ hybridization whether chronic intrahypothalamic desipramine can suppress retrogradely NE transporter, tyrosine hydroxylase, or NPY mRNAs in brainstem NE cells.
Aim 4 b will search for evidence of E2 downregulation of NE transporter message in NE neurons. These studies will indicate the importance of specific neurochemical on GnRH secretion thereby increasing the knowledge of biological and pathological events in fertile and neurally depressed, infertile female primates.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD016631-14
Application #
2392342
Study Section
Reproductive Biology Study Section (REB)
Project Start
1982-09-01
Project End
1999-03-31
Budget Start
1997-04-01
Budget End
1998-03-31
Support Year
14
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Oregon Regional Primate Research Center
Department
Type
DUNS #
City
Beaverton
State
OR
Country
United States
Zip Code
97006
Smith, Jeremy T; Shahab, Muhammad; Pereira, Alda et al. (2010) Hypothalamic expression of KISS1 and gonadotropin inhibitory hormone genes during the menstrual cycle of a non-human primate. Biol Reprod 83:568-77
Pau, K Y; Hess, D L; Kohama, S et al. (2000) Oestrogen upregulates noradrenaline release in the mediobasal hypothalamus and tyrosine hydroxylase gene expression in the brainstem of ovariectomized rhesus macaques. J Neuroendocrinol 12:899-909
Pau, C Y; Pau, K Y; Spies, H G (1998) Putative estrogen receptor beta and alpha mRNA expression in male and female rhesus macaques. Mol Cell Endocrinol 146:59-68
Pau, K Y; Yu, J H; Lee, C J et al. (1998) Topographic localization of neuropeptide Y mRNA in the monkey brainstem. Regul Pept 75-76:145-53
Urbanski, H F; Pau, K Y (1998) A biphasic developmental pattern of circulating leptin in the male rhesus macaque (Macaca mulatta). Endocrinology 139:2284-6
Pau, K Y; Spies, H G (1997) Neuroendocrine signals in the regulation of gonadotropin-releasing hormone secretion. Chin J Physiol 40:181-96
Spies, H G; Pau, K Y; Yang, S P (1997) Coital and estrogen signals: a contrast in the preovulatory neuroendocrine networks of rabbits and rhesus monkeys. Biol Reprod 56:310-9
Pau, K Y; Berria, M; Hess, D L et al. (1996) Opiatergic influence on gonadotropin-releasing hormone and luteinizing hormone release during the macaque menstrual cycle. Biol Reprod 55:478-84
Pau, K Y; Berria, M; Hess, D L et al. (1995) Hypothalamic site-dependent effects of neuropeptide Y on gonadotropin-releasing hormone secretion in rhesus macaques. J Neuroendocrinol 7:63-7
Pau, K Y; Berria, M; Hess, D L et al. (1993) Preovulatory gonadotropin-releasing hormone surge in ovarian-intact rhesus macaques. Endocrinology 133:1650-6

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