Gonadotropin-releasing hormone receptor gene expression in rat anterior pituitary

Mertani, Hichem C.; Testart, Catherine; Ouhtit, Allal; Brisson, Christine; Morel, Gérard

doi:10.1007/bf02782760

Cited by 3 publications

(2 citation statements)

References 21 publications

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“…Either this treatment stimulates the production of an inhibitory factor by gonadotrophs, or inhibits a stimulating factor which is unavailable or in too low a concentration to maintain prolactin levels. It cannot be ruled out that GnRH may act directly on lactotrophs because GnRH receptor mRNA has been found in adult rat lactotrophs (41). However, at least in the rat, GnRH has no effect on a purified population of lactotrophs (10).…”

Section: Discussionmentioning

confidence: 99%

Stimulating Effect of Glycoprotein Hormone Free α‐Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50‐Day Ovine Foetal Pituitary Explants

Chabot

Gauthier

Combarnous

et al. 2001

J Neuroendocrinology

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The aim of our study was to determine whether free a of glycoprotein hormones (free a) plays a role in lactotroph function during early pituitary development in the sheep foetus. Detection and quanti®cation of free a, luteinzing hormone b-subunit (LHb) and prolactin immunolabelling were determined by immunocytochemistry at days 32, 37, 42, 50 and 63 of gestation. Free a-and LHbcontaining cells were ®rst detected in the ovine foetal pituitary gland on day 37 of gestation, while prolactin-containing cells were ®rst identi®ed on day 42. Analysis of serial sections suggested that free a immunoreactive cells were also LHb-positive, indicating that free a was mainly synthesized by gonadotrophs. In early foetal stages, free a occurred in the antero-medio ventral region of the pituitary gland, whereas prolactin-containing cells were more dorsally and more caudally localized. The free a-, LHb-and prolactin-immunostained area increased markedly between days 50 and 63 of gestation. To evaluate a possible functional relationship between gonadotrophs and lactotrophs, the effects of free a or gonadotropin releasing hormone (GnRH) on prolactin release were assayed. Chronic treatment of pituitary explants from male and female 42-day-old ovine foetuses for 8 days with 10 x9 or 10 x7 M ovine free a did not affect prolactin release. By contrast, free a administration on pituitary explants from male and female 50-day-old foetuses resulted in enhanced prolactin release. At this age, a daily (2 h per day) treatment with 10 x8 M GnRH had similar stimulatory effect to free a whereas a`®rst day' treatment (24 h on the ®rst day) reduced prolactin release throughout the culture in males and had no effect in females. These results indicate that, despite early detection of free a at day 37 in the ovine foetal pituitary, its stimulatory effect on prolactin release occurs from day 50 of gestation, corresponding to the ®rst period of lactotroph development in vivo. A daily treatment with GnRH mimics the effect of free a on prolactin release.

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Section: Discussionmentioning

confidence: 99%

Stimulating Effect of Glycoprotein Hormone Free α‐Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50‐Day Ovine Foetal Pituitary Explants

Chabot

Gauthier

Combarnous

et al. 2001

J Neuroendocrinology

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“…Although further studies are needed, it is possible that gonadotropes are the primary cell type responsible for supplying ANXA5 in the pituitary gland. Alternatively, as the GnRH receptor is found not only in gonadotropes but also lactotropes [15], GnRH could also act through this cell type. If this is the case, GnRH could affect the function of lactotropes through ANXA5 synthesis, as GnRH has been shown to modify prolactin secretion [16].…”

Section: Resultsmentioning

confidence: 99%

Gonadotropin-releasing hormone is prerequisite for the constitutive expression of pituitary annexin A5

et al. 2015

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ANNEXIN A5 (ANXA5) is a member of the annexin family of structurally related proteins, which are characterized by calcium-dependent phospholipid binding [1,2]. Although found in a variety of tissues, the distribution of ANXA5 is specific to cell type [3,4]. We previously reported that ANXA5 is expressed in gonadotropes of the anterior pituitary gland and that its expression is enhanced after ovariectomy in rats [4,5]. We also demonstrated that gonadotropin-releasing hormone (GnRH) stimulates ANXA5 synthesis in vivo and in vitro [6,7], indicating the expression of ANXA5 is directly regulated by the GnRH receptor. Finally, we showed that the suppression of ANXA5 synthesis with antisense oligonucleotides retards GnRH-stimulated luteinizing hormone (LH) release [8].Gonadotropin-releasing hormone is prerequisite for the constitutive expression of pituitary annexin A5 Abstract. Annexin A5 (ANXA5), a member of the structurally related family of annexin proteins, is expressed in pituitary gonadotropes. We previously reported that ANXA5 expression is stimulated by gonadotropin-releasing hormone (GnRH).In the present study, we investigated ANXA5 expression in the anterior pituitary gland of GnRH-deficient mutant hypogonadal (hpg) mice. RT-PCR demonstrated that luteinizing hormone β subunit (LHβ) and ANXA5 mRNA levels were both lower in the pituitary gland of hpg mice than in wild-type mice. Immunohistochemistry showed that ANXA5 expression throughout the pituitary gland was very low in hpg mice, suggesting that ANXA5 is diminished in gonadotropes and also in other cell types. Subcutaneous administration of a GnRH analogue, des-gly10 (Pro9)-GnRH ethylamide (1 µg/ day for 7 days), augmented the expression of LHβ and ANXA5 in the pituitary gland in hpg mice. However, LHβ-and ANXA5-positive cells did not show exactly matched spatial distributions. These findings suggest that GnRH is necessary for constitutive ANXA5 expression in the pituitary gland, not only in gonadotropes but also in other pituitary gland cell types. A close relationship between ANXA5 and LHβ expression was confirmed. It is suggested that a significant role of ANXA5 in the physiologic secretion of LH.

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Stimulating Effect of Glycoprotein Hormone Free alpha-Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50-Day Ovine Foetal Pituitary Explants

Chabot¹,

Gauthier²,

Combarnous³

et al. 2001

J Neuroendocrinol

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The aim of our study was to determine whether free alpha of glycoprotein hormones (free alpha) plays a role in lactotroph function during early pituitary development in the sheep foetus. Detection and quantification of free alpha, luteinzing hormone beta-subunit (LHbeta) and prolactin immunolabelling were determined by immunocytochemistry at days 32, 37, 42, 50 and 63 of gestation. Free alpha- and LHbeta-containing cells were first detected in the ovine foetal pituitary gland on day 37 of gestation, while prolactin-containing cells were first identified on day 42. Analysis of serial sections suggested that free alpha immunoreactive cells were also LHbeta-positive, indicating that free alpha was mainly synthesized by gonadotrophs. In early foetal stages, free alpha occurred in the antero-medio ventral region of the pituitary gland, whereas prolactin-containing cells were more dorsally and more caudally localized. The free alpha-, LHbeta- and prolactin-immunostained area increased markedly between days 50 and 63 of gestation. To evaluate a possible functional relationship between gonadotrophs and lactotrophs, the effects of free alpha or gonadotropin releasing hormone (GnRH) on prolactin release were assayed. Chronic treatment of pituitary explants from male and female 42-day-old ovine foetuses for 8 days with 10-9 or 10-7 M ovine free alpha did not affect prolactin release. By contrast, free alpha administration on pituitary explants from male and female 50-day-old foetuses resulted in enhanced prolactin release. At this age, a daily (2 h per day) treatment with 10-8 M GnRH had similar stimulatory effect to free alpha whereas a 'first day' treatment (24 h on the first day) reduced prolactin release throughout the culture in males and had no effect in females. These results indicate that, despite early detection of free alpha at day 37 in the ovine foetal pituitary, its stimulatory effect on prolactin release occurs from day 50 of gestation, corresponding to the first period of lactotroph development in vivo. A daily treatment with GnRH mimics the effect of free alpha on prolactin release.

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Gonadotropin-releasing hormone receptor gene expression in rat anterior pituitary

Cited by 3 publications

References 21 publications

Stimulating Effect of Glycoprotein Hormone Free α‐Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50‐Day Ovine Foetal Pituitary Explants

Stimulating Effect of Glycoprotein Hormone Free α‐Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50‐Day Ovine Foetal Pituitary Explants

Gonadotropin-releasing hormone is prerequisite for the constitutive expression of pituitary annexin A5

Stimulating Effect of Glycoprotein Hormone Free alpha-Subunit and Daily Gonadotropin Releasing Hormone Treatment on Prolactin Release from 50-Day Ovine Foetal Pituitary Explants

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