The Distribution of Progesterone Receptor Immunoreactivity and mRNA in the Preoptic Area and Hypothalamus of the Ewe: Upregulation of Progesterone Receptor mRNA in the Mediobasal Hypothalamus by Oestrogen

Scott, Chris J; Pereira, Alda; Rawson, John A; Simmons, Donna M.; Rossmanith, W. G.; Ing, Nancy H.; Clarke, Iain J.

doi:10.1046/j.1365-2826.2000.00490.x

Cited by 58 publications

(44 citation statements)

References 66 publications

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“…Alternatively then, the two steroids might have interacted to impair the secretion of LH by one of the steroids inducing an increase in the number of receptors for the other steroid in the hypothalamus. We previously found an interaction of this nature in ewes where oestrogen increased the number of progesterone receptors in the ventromedial nucleus and arcuate nucleus in the ewe (Scott et al 2000). Oestrogen had a similar action on hypothalamic progesterone receptors in male guinea pigs (Dufourny et al 1997) but such interactions have not been studied in rams.…”

Section: Discussionmentioning

confidence: 99%

“…The procedures used for 35 S-labelling of the probe, hybridisation and pre/post hybridisation washes have been described in detail previously (Scott et al 2000). Following completion of the post-hybridisation treatments, the sections were exposed to Kodak BMR film for 3-5 days, then dipped in Ilford K5 photographic emulsion and exposed for 2 weeks.…”

Section: Experiments 2: In Situ Hybridisation Of Mrna For Progesteronementioning

confidence: 99%

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Progesterone and testosterone in combination act in the hypothalamus of castrated rams to regulate the secretion of LH

Turner

Tilbrook²,

Clarke³

et al. 2001

Journal of Endocrinology

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We tested the hypotheses that progesterone enhances the negative feedback actions of testosterone in rams and that this occurs through actions at the hypothalamus. In the first part of this study, blood samples were collected every 10 min for 12 h before and after 7 days of treatment (i.m.) of castrated Romney Marsh rams (n=5 per group) with vehicle, progesterone (4 mg/12 h), testosterone (4 mg/12 h) or a combination of progesterone (4 mg/12 h) and testosterone (4 mg/12 h). In the second part of this study the brains of four gonad-intact Romney Marsh rams were collected, the hypothalamus was sectioned and in situ hybridisation of mRNA for progesterone receptors conducted. After 7 days of treatment with vehicle or progesterone or testosterone alone, there were no changes in the secretion of LH. In contrast, treatment with a combination of progesterone and testosterone resulted in a significant (P<0·01, repeated measures ANOVA) decrease in mean plasma concentrations of LH, the number of LH pulses per hour and the pre-LH pulse nadir and a significant (P<0·01) increase in the inter-LH pulse interval. We found cells containing mRNA for progesterone receptors throughout the hypothalamus, including the preoptic area (where most GnRH neurons are located in sheep), the periventricular, ventromedial and arcuate nuclei and the bed nucleus of the stria terminalis. This study shows that progesterone is capable of acting centrally with testosterone to suppress the secretion of LH in castrated rams and that cells containing mRNA for progesterone receptors are located in the hypothalamus of rams in the vicinity of GnRH neurons.

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Section: Discussionmentioning

confidence: 99%

Section: Experiments 2: In Situ Hybridisation Of Mrna For Progesteronementioning

confidence: 99%

Progesterone and testosterone in combination act in the hypothalamus of castrated rams to regulate the secretion of LH

Turner

Tilbrook²,

Clarke³

et al. 2001

Journal of Endocrinology

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“…On the other hand, there is strong in vivo evidence of genomic and membrane actions of P, as well as ligand-independent P receptor activation in the regulation of lordosis behavior and gonadotrophin release (Bellido et al 1999, Schumacher et al 1999, Chappell & Levine 2000, Auger 2001, Mani 2001. E 2 induces the expression of P receptors in the pituitary and hypothalamus, with the highest level in the proestrus (Guerra-Araiza et al 2000, Scott et al 2000, Turgeon & Waring 2000. We may infer that the reduction in E 2 secretion on the proestrus day decreased P receptor expression and thus it could have affected the lordosis response in the neonatal handled females.…”

Section: Discussionmentioning

confidence: 99%

Neonatal handling and reproductive function in female rats

Gomes¹,

Raineki²,

Paula³

et al. 2005

Journal of Endocrinology

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Neonatal handling induces anovulatory estrous cycles and decreases sexual receptivity in female rats. The synchronous secretion of hormones from the gonads (estradiol (E 2 ) and progesterone (P)), pituitary (luteinizing (LH) and follicle-stimulating (FSH) hormones) and hypothalamus (LH-releasing hormone (LHRH)) are essential for the reproductive functions in female rats. The present study aimed to describe the plasma levels of E 2 and P throughout the estrous cycle and LH, FSH and prolactin (PRL) in the afternoon of the proestrus, and the LHRH content in the medial preoptic area (MPOA), median eminence (ME) and medial septal area (MSA) in the proestrus, in the neonatal handled rats. Wistar pup rats were handled for 1 min during the first 10 days after delivery (neonatal handled group) or left undisturbed (nonhandled group). When they reached adulthood, blood samples were collected through a jugular cannula and the MPOA, ME and MSA were microdissected. Plasma levels of the hormones and the content of LHRH were determined by RIA. The number of oocytes counted in the morning of the estrus day in the handled rats was significantly lower than in the nonhandled ones. Neonatal handling reduces E 2 levels only on the proestrus day while P levels decreased in metestrus and estrus. Handled females also showed reduced plasma levels of LH, FSH and PRL in the afternoon of the proestrus. The LHRH content in the MPOA was significantly higher than in the nonhandled group. The reduced secretion of E 2 , LH, FSH and LHRH on the proestrus day may explain the anovulatory estrous cycle in neonatal handled rats. The reduced secretion of PRL in the proestrus may be related to the decreased sexual receptiveness in handled females. In conclusion, early-life environmental stimulation can induce long-lasting effects on the hypothalamus-pituitary-gonad axis .

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“…LH (and by inference GnRH) pulse frequency slows coincidentally with P increases in the luteal phase, and administration of P to women during the follicular phase slows GnRH pulse frequency (34). Progesterone's ability to slow GnRH pulse frequency appears to require the permissive presence of estradiol (E 2 ) (7,24,33), probably reflecting the ability of E 2 to induce hypothalamic P receptors (18,27,31,32).…”

mentioning

confidence: 99%

Progesterone acutely increases LH pulse amplitude but does not acutely influence nocturnal LH pulse frequency slowing during the late follicular phase in women

McCartney¹,

Blank²,

Marshall³

2007

American Journal of Physiology-Endocrinology and Metabolism

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(P) is the primary effector of LH (and by inference gonadotropin-releasing hormone) pulse frequency slowing in cycling women, but the time course of this action is unclear. We hypothesized that P administration to estradiol (E 2)-pretreated women would slow LH pulse frequency within 12 h. We studied eight normally cycling women in two separate cycles (follicular phase, cycle days 7-11). After 3 days of E 2 pretreatment (0.2 mg/day via transdermal patches), a 25-h blood sampling protocol (starting at 0800) was performed to define LH pulsatility. Oral micronized P (100 mg) or placebo (PBO) was administered at 1800 in a randomized, double-blind fashion, with treatment crossover occurring during a subsequent cycle. The 10-h mean P concentration increased from 0.6 Ϯ 0.1 ng/ml before P (0800 -1800) to 3.9 Ϯ 0.3 ng/ml after P administration (2200 -0800, P Ͻ 0.01). Ten-hour mean LH interpulse interval increased significantly after both P and PBO administration, with no significant difference between P and PBO. In contrast, mean LH, LH amplitude, and mean FSH increased significantly within 4 h of P administration, but not after PBO. We conclude that, in E 2-pretreated women in the late follicular phase, 1) nocturnal LH pulse frequency is not acutely (within 12 h) influenced by P administration; 2) an acute increase in P causes pronounced augmentation of gonadotropin pulse amplitude within 4 h; and 3) LH pulse frequency slows overnight during the second half of the follicular phase. luteinizing hormone; gonadotropin-releasing hormone; follicle-stimulating hormone; estradiol; diurnal; circadian PULSATILE GONADOTROPIN-RELEASING HORMONE (GnRH), secreted from a functionally integrated network of hypothalamic neurons called the GnRH pulse generator, stimulates LH and FSH synthesis and pulsatile secretion from pituitary gonadotropes. Variations in GnRH pulse frequency regulate LH␤ and FSH␤ transcription and mRNA expression (2, 4) and contribute to differential secretion of LH and FSH throughout ovulatory cycles (8,11,19,39). Progesterone (P) appears to be the primary effector of GnRH pulse frequency slowing in adult women. LH (and by inference GnRH) pulse frequency slows coincidentally with P increases in the luteal phase, and administration of P to women during the follicular phase slows GnRH pulse frequency (34). Progesterone's ability to slow GnRH pulse frequency appears to require the permissive presence of estradiol (E 2 ) (7,24,33), probably reflecting the ability of E 2 to induce hypothalamic P receptors (18,27,31,32).Some animal studies suggest that P suppression of GnRH pulse frequency occurs rapidly. For instance, in ovariectomized but E 2 -replete ewes, P dramatically suppresses GnRH pulse frequency over 12 h; this effect appears to begin within 2 h and is blocked by the P receptor antagonist mifepristone (RU-486) (33). Similarly, in bovine females, changes in LH pulse frequency are observed within 6 h of altered P concentrations (1).In women, some hypothalamic-pituitary effects of P, such as increases of LH in E 2 -...

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The Distribution of Progesterone Receptor Immunoreactivity and mRNA in the Preoptic Area and Hypothalamus of the Ewe: Upregulation of Progesterone Receptor mRNA in the Mediobasal Hypothalamus by Oestrogen

Cited by 58 publications

References 66 publications

Progesterone and testosterone in combination act in the hypothalamus of castrated rams to regulate the secretion of LH

Progesterone and testosterone in combination act in the hypothalamus of castrated rams to regulate the secretion of LH

Neonatal handling and reproductive function in female rats

Progesterone acutely increases LH pulse amplitude but does not acutely influence nocturnal LH pulse frequency slowing during the late follicular phase in women

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