The G. W. Harris Lecture Steroid Control of Brain and Pituitary Function

Fink, George

doi:10.1113/expphysiol.1988.sp003145

Cited by 50 publications

(22 citation statements)

References 64 publications

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“…In rodents, the amplitude of the GnRH surge has been reported to be too small to trigger a LH surge without an accompanying increase in pituitary responsiveness to GnRH (44,45). An increase in GnRH receptor expression in the pituitary before an estradiol-induced LH surge has been demonstrated in monkeys and sheep (46,47).…”

Section: Discussionmentioning

confidence: 99%

Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

Christian

Mobley

Moenter

2005

Proc. Natl. Acad. Sci. U.S.A.

192

213

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A robust gonadotropin-releasing hormone (GnRH) surge is a prerequisite signal for the luteinizing hormone (LH) surge that triggers ovulation. In rodents, the GnRH surge is initiated by elevated estradiol and a diurnal switch in estrogen action from negative to positive feedback. The ability of constant estradiol treatment to induce daily LH surges was tested in adult mice that were ovariectomized (OVX) or OVX and treated with estradiol implants (OVX؉E). LH in OVX mice showed no time-of-day difference. In contrast, OVX؉E mice showed a large LH surge (8-to 124-fold relative to the a.m.) in p.m. samples on d 2-5 post-OVX؉E. Targeted extracellular recordings were used to examine changes in firing activity of GnRH neurons in brain slices. There was no time-of-day difference in cells from OVX mice. In contrast, OVX؉E cells recorded in the p.m. showed an increased mean firing rate and instantaneous firing frequency, which could increase GnRH release, and decreased duration of quiescence between bouts of firing, possibly reflecting increased pulse frequency, compared with cells recorded in the a.m. In the a.m., OVX؉E cells showed changes in GnRH neuron firing reflecting negative feedback compared with OVX cells, whereas in the p.m., OVX؉E cells exhibited changes suggesting positive feedback. These data indicate that differences in pattern and level of individual GnRH neuron firing may reflect the switch in estradiol action and underlie GnRH surge generation. The persistence of altered GnRH neuron activity in slices indicates that this approach can be used to study the neurobiological mechanisms of surge generation.luteinizing hormone ͉ mouse model ͉ surge ͉ electrophysiology ͉ neuroendocrinology

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Section: Discussionmentioning

confidence: 99%

Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

Christian

Mobley

Moenter

2005

Proc. Natl. Acad. Sci. U.S.A.

192

213

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“…In vertebrate animals, sex steroid hormones, such as estrogen, progesterone and androgen, not only stimulate gonadal maturation directly, but also work through a feedback mechanism via combining with the related receptors in the brain (Fink 1988;Trudeau et al 1993;Yuan et al 1995). It has been reported that sex steroid hormones occur and modulate gonadal maturation in crustaceans for many years (Fingerman 1997;Huberman 2000).…”

Section: Introductionmentioning

confidence: 98%

The identification and distribution of progesterone receptors in the brain and thoracic ganglion in the mud crab Scylla paramamosain (Crustacea: Decapoda: Brachyura)

Huang

Song

et al. 2010

Invert Neurosci

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The existence of progesterone receptors (PR) in the Scylla paramamosain (mud crab) was studied using immunological techniques. By Western blotting, PR with an apparent molecular weight of 70 kDa is identified in both the brain and the thoracic ganglion. By immunohistochemistry, PR immunoreactive neurons are detected mainly in the protocerebrum, the subesophageal ganglion and the leg ganglion. PR immunoreactivity is localized mainly in the nuclei of these neurons, while only a few neurons show such activities in their cytoplasm. Our results provide evidence that progesterone modulates the neuroendocrine system mainly via nucleus receptors.

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“…Metestrus is the stage in the 4-day cycle when estrogens and progesterone are at their lowest levels in the circulation. 9 Anesthesia was induced (5%) and maintained (1% to 2%) by halothane in oxygen-nitrous oxide (30:70). A distal segment of the left MCA was occluded by electrocoagulation in male and female SHRSP, WKY, and F 1 crosses 1 and 2 (nϭ6 to 10) using the technique of Tamura et al, 10 with monitoring of physiological variables throughout MCAO and at 24 hours after MCAO as previously described.…”

Section: Methodsmentioning

confidence: 99%

Genetic and Gender Influences on Sensitivity to Focal Cerebral Ischemia in the Stroke-Prone Spontaneously Hypertensive Rat

et al. 1999

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Abstract-We have investigated genetic transmission of increased sensitivity to focal cerebral ischemia and the influence of gender in the stroke-prone spontaneously hypertensive rat (SHRSP). Halothane-anesthetized, 3-to 5-month-old male and female Wistar-Kyoto rats (WKY), SHRSP, and the first filial generation rats (F 1 crosses 1 and 2) underwent distal (2 mm) permanent middle cerebral artery occlusion (MCAO) by electrocoagulation. Key Words: rats, stroke-prone spontaneously hypertensive Ⅲ cerebral ischemia, focal Ⅲ gender Ⅲ estrus Ⅲ estrogen Ⅲ middle cerebral artery occlusion T he stroke-prone spontaneously hypertensive rat (SHRSP) was established from Wistar-Kyoto rats (WKY) and is an inbred animal model of cerebrovascular disease. 1 Spontaneous strokes occur in the SHRSP, and the role of a genetic factor in stroke is highlighted by the resistance of the related SHR to spontaneous strokes despite hypertension and similar diets.SHRSP exhibit an increased sensitivity to ischemia and an increased volume of infarction after experimentally induced focal cerebral ischemia compared with their reference strain, the WKY. This has been shown by ligation 2 or electrocoagulation 3,4 of the middle cerebral artery (MCA). One reason for the increased sensitivity of the SHRSP to stroke may be reduced blood flow through collateral vessels between the MCA and anterior and posterior cerebral arteries. The collaterals have been postulated to have an impaired ability to dilate and a smaller internal diameter compared with those in normotensive Wistar rats. 5 In addition, more marked ischemic glutamate increases in SHRSP than WKY may be related to stroke sensitivity. 6 Recently, we revealed a genetic component to the increased sensitivity after experimental ischemia in the SHRSP. We linked increased volume of infarction 24 hours after MCA occlusion (MCAO) to a locus on rat chromosome 5 with a logarithm of odds (LOD) of 16.6. 4 Having previously demonstrated a dominant mode of inheritance for this phenotype in F 1 cross 2 hybrid rats (WKY father), 7 we now use a different set of reciprocal crosses especially bred for these experiments to examine genetic transmission and any influence of the origin of the Y chromosome (SHRSP male progenitor versus WKY male progenitor) on infarct volume. We also investigate the effects of sex differences and control for estrous status during ischemia induction-the first F 1 analysis to do so. MethodsAll experiments were carried out under license from the Home Office and were subject to the Animals (Scientific Procedures) Act, 1986. Breeding and housing of SHRSP and WKY have been previously described. 4 Two parental crosses were performed espe-

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The G. W. Harris Lecture Steroid Control of Brain and Pituitary Function

Cited by 50 publications

References 64 publications

Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

Diurnal and estradiol-dependent changes in gonadotropin-releasing hormone neuron firing activity

The identification and distribution of progesterone receptors in the brain and thoracic ganglion in the mud crab Scylla paramamosain (Crustacea: Decapoda: Brachyura)

Genetic and Gender Influences on Sensitivity to Focal Cerebral Ischemia in the Stroke-Prone Spontaneously Hypertensive Rat

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