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Anti-Müllerian hormone: a new actor of sexual dimorphism in pituitary gonadotrope activity before puberty.

Garrel G, Racine C, L'Hôte D, Denoyelle C, Guigon CJ, di Clemente N, Cohen-Tannoudji J - Sci Rep (2016)

Bottom Line: Furthermore, AMH was shown to establish complex interrelations with canonical FSH regulators as it cooperates with activin to induce Fshb expression whereas it reduces BMP2 action.Moreover, AMH specifically regulates FSH and not LH, indicating that AMH is a factor contributing to the differential regulation of gonadotropins.Overall, our study uncovers a new role for AMH in regulating gonadotrope function and suggests that AMH participates in the postnatal elevation of FSH secretion in females.

View Article: PubMed Central - PubMed

Affiliation: Université Paris-Diderot, Sorbonne Paris Cité, Biologie Fonctionnelle et Adaptative (BFA), F-75013 Paris, France.

ABSTRACT
Anti-Müllerian hormone (AMH) contributes to male sexual differentiation and acts on gonads of both sexes. Identification of AMH receptivity in both pituitary and brain has led to the intriguing idea that AMH participates to the hypothalamic-pituitary control of reproduction, however in vivo experimental evidence is still lacking. We show that AMH stimulates secretion and pituitary gene expression of the gonadotropin FSH in vivo in rats. AMH action is sex-dependent, being restricted to females and occurring before puberty. Accordingly, we report higher levels of pituitary AMH receptor transcripts in immature females. We show that AMH is functionally coupled to the Smad pathway in LβT2 gonadotrope cells and dose-dependently increases Fshb transcript levels. Furthermore, AMH was shown to establish complex interrelations with canonical FSH regulators as it cooperates with activin to induce Fshb expression whereas it reduces BMP2 action. We report that GnRH interferes with AMH by decreasing AMH receptivity in vivo in females. Moreover, AMH specifically regulates FSH and not LH, indicating that AMH is a factor contributing to the differential regulation of gonadotropins. Overall, our study uncovers a new role for AMH in regulating gonadotrope function and suggests that AMH participates in the postnatal elevation of FSH secretion in females.

No MeSH data available.


Related in: MedlinePlus

AMH potentiates activin signaling and activin effect on Fshb expression in LβT2 cells.LβT2 cells were stimulated for 4 h with 2.5 μg/ml AMH alone or combined with 10 ng/ml activin A or 20 ng/ml BMP2. (a) AMH enhances activin and counteracts BMP2 stimulation of Fshb expression. Fshb and Lhb mRNA levels were determined by real-time qPCR and expressed as the mean ± SEM of at least 3 independent experiments. (b) AMH improves activin coupling to the Smad2/3 pathway. P-Smad2 protein level was evaluated by immunoblotting and normalized with total Smad2. *P ≤ 0.05; **P ≤ 0.01 compared with control cells. a, P ≤ 0.05 between AMH and AMH+activin treatments. b, P ≤ 0.05 between AMH and AMH+BMP2 treatments.
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f3: AMH potentiates activin signaling and activin effect on Fshb expression in LβT2 cells.LβT2 cells were stimulated for 4 h with 2.5 μg/ml AMH alone or combined with 10 ng/ml activin A or 20 ng/ml BMP2. (a) AMH enhances activin and counteracts BMP2 stimulation of Fshb expression. Fshb and Lhb mRNA levels were determined by real-time qPCR and expressed as the mean ± SEM of at least 3 independent experiments. (b) AMH improves activin coupling to the Smad2/3 pathway. P-Smad2 protein level was evaluated by immunoblotting and normalized with total Smad2. *P ≤ 0.05; **P ≤ 0.01 compared with control cells. a, P ≤ 0.05 between AMH and AMH+activin treatments. b, P ≤ 0.05 between AMH and AMH+BMP2 treatments.

Mentions: We next determined whether AMH could modulate the action of other known potent inducers of Fshb expression such as activin or BMP2. Activin and BMP2 have been reported to activate the Smad2/3 and the Smad1/5/8 respectively in LβT2 cells721. As expected, a 4 h-treatment of LβT2 cells with activin or BMP2 significantly increased Fshb transcript levels (by 29 ± 5 and 18 ± 1 fold, respectively, Fig. 3a). When cells were co-stimulated with AMH and activin, the combined observed effect was greater than the sum of their individual effects, indicating that AMH synergistically cooperates with activin to induce Fshb expression in LβT2 gonadotrope cells. Activin also increased Lhb transcripts levels although to a lesser extent than Fshb but no synergism could be detected for this gene. The synergism between AMH and activin appears thus to be specific of Fshb expression. Contrasting with activin, AMH did not cooperate with BMP2 in inducing Fshb as no synergistic or additive effects could be detected. Instead, AMH inhibited by 25% the action of BMP2 (Fig. 3a). To better understand the mechanisms underlying AMH and activin synergism, we next measured activin signaling in cells co-treated or not with AMH. Although AMH alone did not affect Smad2 phosphorylation, it significantly increased activin-induced P-Smad2 levels (Fig. 3b). Same results were obtained after detection and quantification of P-Smad3 levels (activin-induced phosphorylation of Smad3 was increased by 1.4 ± 0.1 fold in presence of AMH, data not shown). In contrast, no effect of AMH on BMP2 induced phosphorylation of Smad1/5/8 could be detected (1.08 ± 0.03 fold over BMP2, data not shown). Altogether, this indicates that AMH, in addition to its proper effects, potentiates activin signaling and activin-dependent Fshb expression.


Anti-Müllerian hormone: a new actor of sexual dimorphism in pituitary gonadotrope activity before puberty.

Garrel G, Racine C, L'Hôte D, Denoyelle C, Guigon CJ, di Clemente N, Cohen-Tannoudji J - Sci Rep (2016)

AMH potentiates activin signaling and activin effect on Fshb expression in LβT2 cells.LβT2 cells were stimulated for 4 h with 2.5 μg/ml AMH alone or combined with 10 ng/ml activin A or 20 ng/ml BMP2. (a) AMH enhances activin and counteracts BMP2 stimulation of Fshb expression. Fshb and Lhb mRNA levels were determined by real-time qPCR and expressed as the mean ± SEM of at least 3 independent experiments. (b) AMH improves activin coupling to the Smad2/3 pathway. P-Smad2 protein level was evaluated by immunoblotting and normalized with total Smad2. *P ≤ 0.05; **P ≤ 0.01 compared with control cells. a, P ≤ 0.05 between AMH and AMH+activin treatments. b, P ≤ 0.05 between AMH and AMH+BMP2 treatments.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4815011&req=5

f3: AMH potentiates activin signaling and activin effect on Fshb expression in LβT2 cells.LβT2 cells were stimulated for 4 h with 2.5 μg/ml AMH alone or combined with 10 ng/ml activin A or 20 ng/ml BMP2. (a) AMH enhances activin and counteracts BMP2 stimulation of Fshb expression. Fshb and Lhb mRNA levels were determined by real-time qPCR and expressed as the mean ± SEM of at least 3 independent experiments. (b) AMH improves activin coupling to the Smad2/3 pathway. P-Smad2 protein level was evaluated by immunoblotting and normalized with total Smad2. *P ≤ 0.05; **P ≤ 0.01 compared with control cells. a, P ≤ 0.05 between AMH and AMH+activin treatments. b, P ≤ 0.05 between AMH and AMH+BMP2 treatments.
Mentions: We next determined whether AMH could modulate the action of other known potent inducers of Fshb expression such as activin or BMP2. Activin and BMP2 have been reported to activate the Smad2/3 and the Smad1/5/8 respectively in LβT2 cells721. As expected, a 4 h-treatment of LβT2 cells with activin or BMP2 significantly increased Fshb transcript levels (by 29 ± 5 and 18 ± 1 fold, respectively, Fig. 3a). When cells were co-stimulated with AMH and activin, the combined observed effect was greater than the sum of their individual effects, indicating that AMH synergistically cooperates with activin to induce Fshb expression in LβT2 gonadotrope cells. Activin also increased Lhb transcripts levels although to a lesser extent than Fshb but no synergism could be detected for this gene. The synergism between AMH and activin appears thus to be specific of Fshb expression. Contrasting with activin, AMH did not cooperate with BMP2 in inducing Fshb as no synergistic or additive effects could be detected. Instead, AMH inhibited by 25% the action of BMP2 (Fig. 3a). To better understand the mechanisms underlying AMH and activin synergism, we next measured activin signaling in cells co-treated or not with AMH. Although AMH alone did not affect Smad2 phosphorylation, it significantly increased activin-induced P-Smad2 levels (Fig. 3b). Same results were obtained after detection and quantification of P-Smad3 levels (activin-induced phosphorylation of Smad3 was increased by 1.4 ± 0.1 fold in presence of AMH, data not shown). In contrast, no effect of AMH on BMP2 induced phosphorylation of Smad1/5/8 could be detected (1.08 ± 0.03 fold over BMP2, data not shown). Altogether, this indicates that AMH, in addition to its proper effects, potentiates activin signaling and activin-dependent Fshb expression.

Bottom Line: Furthermore, AMH was shown to establish complex interrelations with canonical FSH regulators as it cooperates with activin to induce Fshb expression whereas it reduces BMP2 action.Moreover, AMH specifically regulates FSH and not LH, indicating that AMH is a factor contributing to the differential regulation of gonadotropins.Overall, our study uncovers a new role for AMH in regulating gonadotrope function and suggests that AMH participates in the postnatal elevation of FSH secretion in females.

View Article: PubMed Central - PubMed

Affiliation: Université Paris-Diderot, Sorbonne Paris Cité, Biologie Fonctionnelle et Adaptative (BFA), F-75013 Paris, France.

ABSTRACT
Anti-Müllerian hormone (AMH) contributes to male sexual differentiation and acts on gonads of both sexes. Identification of AMH receptivity in both pituitary and brain has led to the intriguing idea that AMH participates to the hypothalamic-pituitary control of reproduction, however in vivo experimental evidence is still lacking. We show that AMH stimulates secretion and pituitary gene expression of the gonadotropin FSH in vivo in rats. AMH action is sex-dependent, being restricted to females and occurring before puberty. Accordingly, we report higher levels of pituitary AMH receptor transcripts in immature females. We show that AMH is functionally coupled to the Smad pathway in LβT2 gonadotrope cells and dose-dependently increases Fshb transcript levels. Furthermore, AMH was shown to establish complex interrelations with canonical FSH regulators as it cooperates with activin to induce Fshb expression whereas it reduces BMP2 action. We report that GnRH interferes with AMH by decreasing AMH receptivity in vivo in females. Moreover, AMH specifically regulates FSH and not LH, indicating that AMH is a factor contributing to the differential regulation of gonadotropins. Overall, our study uncovers a new role for AMH in regulating gonadotrope function and suggests that AMH participates in the postnatal elevation of FSH secretion in females.

No MeSH data available.


Related in: MedlinePlus