Increase of Gonadotropin-Releasing Hormone Concentration in Pituitary Portal Blood after Substance P Administration in Male Rats

Walczewska, Anna; Szkudlarek, Urszula; Jakubowska-Naziemblo, B; Dziedzic, Barbara; Traczyk, W

doi:10.1159/000054317

Cited by 3 publications

(1 citation statement)

References 42 publications

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“…The former is supported by the expression of ERα and ERβ in rat pituitary [16]. The latter is based on the proven expression of ER subtypes in GnRH neurons and other hypothalamic cell types involved in the control of GnRH release [4, 33, 34, 35, 36], as well as on the ability of estrogen to inhibit GnRH gene expression in vitro and GnRH release to portal circulation in vivo [3, 4, 37]. Moreover, defective GnRH release has been pointed out as the major cause of reduced gonadotropin secretion in neonatally estrogenized male rats [26].…”

Section: Methodsmentioning

confidence: 99%

Neonatal Imprinting and Regulation of Estrogen Receptor Alpha and Beta mRNA Expression by Estrogen in the Pituitary and Hypothalamus of the Male Rat

et al. 2001

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In male rodents, complete reproductive function is critically dependent on adequate estrogen action at different levels of the hypothalamic-pituitary-testicular axis. However, administration of high doses of estrogen during the critical period of neonatal differentiation results in multiple defects in the reproductive axis that disrupt male fertility, the molecular mechanism(s) behind such a phenotype remaining poorly characterized. The aim of this study was twofold: (1) to characterize the effects of neonatal estrogenization upon the pattern of estrogen receptors ERα and ERβ mRNA expression in the pituitary and hypothalamus of the male rat, and (2) to evaluate the ability of estrogen to acutely regulate pituitary and hypothalamic ERα and ERβ mRNA expression in the male rat. To achieve the first goal, groups of male rats were treated on the first day of life with estradiol benzoate (EB; 500 µg/rat), and pituitary and hypothalamic expression of ERα and ERβ mRNA levels were assayed by semiquantitative RT-PCR at different ages from the neonatal period until adulthood (days 1–75 of life). In addition, the mechanism(s) of altered pituitary expression of ERα and ERβ messages in neonatally estrogenized rats was explored by comparison of the effects of neonatal treatment with estrogen or a potent gonadotropin-releasing hormone (GnRH) antagonist. For the second goal, the acute effects of a single dose of EB (12.5–25 µg/rat) on hypothalamic and pituitary ERα and ERβ mRNA expression were assessed in prepubertal and adult male rats. Neonatal estrogenization permanently decreased pituitary ERα and ERβ mRNA expression levels respective to control values at all ages studied. This pattern of response was similar to the short-term effects of neonatal blockade of endogenous GnRH actions. In contrast, neonatal exposure to estrogen transiently increased the hypothalamic expression levels of ERα and ERβ messages. This effect was detected in neonatal (5-day-old), infantile (15-day-old) and prepubertal (30-day-old) rats, and it disappeared at puberty. In addition, estrogen was able to acutely regulate mRNA expression levels of its cognate receptor subtypes in the pituitary and hypothalamus of intact male rats. In adult (75-day-old) males, EB administration (25 µg/rat) induced a significant time-dependent decrease in pituitary ERα and ERβ mRNA levels. In contrast hypothalamic expression of ERα and ERβ messages was increased after acute exposure to EB (12.5 µg/rat) in prepubertal males (30 days old); yet differences in the time course of the response to estrogen were noticed between targets. In conclusion, our data indicate that estrogen is able to neonatally imprint and acutely regulate mRNA expression levels of ERα and ERβ in the pituitary and hypothalamus of the male rat. Regulation of pituitary and hypothalamic ERα and ERβ gene expression by the cognate ligand represents a novel mechanism whereby estrogen modulates its own biological actions upon different levels of the male reproductive axis throughout the life span.

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Section: Methodsmentioning

confidence: 99%

Neonatal Imprinting and Regulation of Estrogen Receptor Alpha and Beta mRNA Expression by Estrogen in the Pituitary and Hypothalamus of the Male Rat

et al. 2001

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Effects of capsaicin on ovarian granulosa cell proliferation and apoptosis

Guler

Zık

2018

Cell Tissue Res

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Capsaicin is the pungent ingredient in red peppers. Due to the effects on the sensory nerve fibers, capsaicin has been used to treat pain and inflammation associated with a variety of diseases including rheumatoid arthritis and diabetic neuropathy, obesity, and cardiovascular and gastrointestinal conditions. Despite the extensive publications on different systems, the studies of the effects on the ovary are very limited. The present study was conducted to examine the possible proliferative and/or apoptotic effects of various doses of capsaicin on primarily derived granulosa cells. In accordance with this purpose, ovarian granulosa cells were exposed to different doses of capsaicin for 24 and 48 h. The proliferative effects of capsaicin were examined by immunocytochemistry, immunofluorescence, and western blot using an antibody against proliferating cell nuclear antigen (PCNA) and cell viability assay (MTT). The effects on apoptosis were determined by immunocytochemistry and immunofluorescence using antibodies against cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP). We showed that the number of apoptotic cells increased in a capsaicin dose and time-dependent manners. We found that a low dose of CAP in 24 h administration was more effective on granulosa cell proliferation. Our results suggest that low-dose and short-term administration of CAP may have a positive effect on ovarian folliculogenesis.

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Close Juxtapositions between LHRH Immunoreactive Neurons and Substance P Immunoreactive Axons in the Human Diencephalon

Dudás

Merchenthaler²

2002

The Journal of Clinical Endocrinology & Metabolism

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LHRH release is induced by substance P (SP) in the rat hypothalamus. Recent immunocytochemical studies indicate that SP-immunoreactive axons synapse on LHRH neurons in the diencephalon of the rat, but this phenomenon has not yet been demonstrated in human. Therefore, in the present study we visualized the SP- and LHRH-immunoreactive (IR) elements in the human diencephalon and evaluated the close juxtapositions between them. The distribution of LHRH- and SP-IR sites were investigated in diencephalic sections of six, postmortem human brains by means of double-labeling immunocytochemistry. The LHRH-containing perikarya were located in the diagonal band of Broca, lamina terminalis cinerea, preopticoseptal, medial preoptic, and infundibular areas of the brain. The SP-IR fibers formed a network in the periventricular zone in the infundibular region, median eminence, and corpus striatum. The SP-IR cell bodies were located mainly in the infundibular region, median eminence, basal part of the periventricular area, dorsomedial subdivision of the ventromedial nucleus, and basal perifornical area of the tuberal region. The juxtapositions between LHRH-IR cell bodies and SP-IR varicosities were detected in the infundibular and periventricular regions. In these sites black, silver-intensified, SP-IR fiber varicosities abutted on brown, DAB-labeled, LHRH-IR cell bodies. Similar structures were detected between the SP-IR fibers and SP-IR perikarya. These findings suggest that the juxtapositions between the SP and LHRH systems may be the morphological basis of SP-controlled LHRH release in the human diencephalon. Moreover, the intimate contacts between SP-IR fiber varicosities and SP-IR cell bodies or axons indicate direct control of SP on the diencephalic SP release.

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Increase of Gonadotropin-Releasing Hormone Concentration in Pituitary Portal Blood after Substance P Administration in Male Rats

Cited by 3 publications

References 42 publications

Neonatal Imprinting and Regulation of Estrogen Receptor Alpha and Beta mRNA Expression by Estrogen in the Pituitary and Hypothalamus of the Male Rat

Neonatal Imprinting and Regulation of Estrogen Receptor Alpha and Beta mRNA Expression by Estrogen in the Pituitary and Hypothalamus of the Male Rat

Effects of capsaicin on ovarian granulosa cell proliferation and apoptosis

Close Juxtapositions between LHRH Immunoreactive Neurons and Substance P Immunoreactive Axons in the Human Diencephalon

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