α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat
Polyamines play an essential role in tissue growth and differentiation, in body weight increment, in brain organization, and in the molecular mechanisms of hormonal action, intracellular signaling, and cell-to-cell communication. In a previous study, inhibition of their synthesis by α- difluoromethy...
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1997
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v215_n2_p192_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v215_n2_p192_Thyssen |
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paper:paper_00379727_v215_n2_p192_Thyssen2023-06-08T15:02:25Z α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat eflornithine follitropin gonadorelin luteinizing hormone polyamine prolactin animal experiment animal model animal tissue article controlled study delayed puberty female follitropin blood level gonadorelin release immaturity luteinizing hormone release nonhuman prolactin release rat Animals Eflornithine Female Follicle Stimulating Hormone Gonadotropin-Releasing Hormone Luteinizing Hormone Pituitary Gland, Anterior Potassium Prolactin Rats Rats, Sprague-Dawley Receptors, LHRH Secretory Rate Animalia Polyamines play an essential role in tissue growth and differentiation, in body weight increment, in brain organization, and in the molecular mechanisms of hormonal action, intracellular signaling, and cell-to-cell communication. In a previous study, inhibition of their synthesis by α- difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase, during development in female rats, was followed by prolonged high follicle-stimulating hormone (FSH) serum level and a delayed puberty onset. Those changes were relatively independent of body mass and did not impair posterior fertility. The present work studies the mechanisms and site of action of polyamine participation in FSH secretion during development. DFMO was injected in female rats between Days 1 and 9 on alternate days. At 10 days of age, hypothalami from control and DFMO rats were perifused in vitro, and basal and potassium-induced gonadotropin- releasing hormone (GnRH) release were measured. The response to membrane depolarization was altered in DFMO hypothalami. Increased GnRH release in response to a low K + concentration was evidenced. Adenohypophyses of the same treated prepubertal rats were perifused in vitro and the response to GnRH pulses was checked. In DFMO-treated rats, higher FSH release was observed, with no changes in LH or PRL secretion. Finally, pituitary GnRH receptor number in adenohypophyseal membranes from treated and control groups was quantified. A significant reduction in specific binding was evident in hypophyses from DFMO-treated rats when compared with binding in the control group. In summary, DFMO treatment in a critical developmental period in the female rat impacts the immature GnRH neuronal network and immature gonadotropes. A delay in maturation is evidenced by a higher sensitivity to secretagogs in both pituitary glands and hypothalamic explants. These events could explain the prolonged high FSH serum levels and delayed puberty onset seen in this experimental model. 1997 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v215_n2_p192_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v215_n2_p192_Thyssen |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
eflornithine follitropin gonadorelin luteinizing hormone polyamine prolactin animal experiment animal model animal tissue article controlled study delayed puberty female follitropin blood level gonadorelin release immaturity luteinizing hormone release nonhuman prolactin release rat Animals Eflornithine Female Follicle Stimulating Hormone Gonadotropin-Releasing Hormone Luteinizing Hormone Pituitary Gland, Anterior Potassium Prolactin Rats Rats, Sprague-Dawley Receptors, LHRH Secretory Rate Animalia |
| spellingShingle |
eflornithine follitropin gonadorelin luteinizing hormone polyamine prolactin animal experiment animal model animal tissue article controlled study delayed puberty female follitropin blood level gonadorelin release immaturity luteinizing hormone release nonhuman prolactin release rat Animals Eflornithine Female Follicle Stimulating Hormone Gonadotropin-Releasing Hormone Luteinizing Hormone Pituitary Gland, Anterior Potassium Prolactin Rats Rats, Sprague-Dawley Receptors, LHRH Secretory Rate Animalia α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| topic_facet |
eflornithine follitropin gonadorelin luteinizing hormone polyamine prolactin animal experiment animal model animal tissue article controlled study delayed puberty female follitropin blood level gonadorelin release immaturity luteinizing hormone release nonhuman prolactin release rat Animals Eflornithine Female Follicle Stimulating Hormone Gonadotropin-Releasing Hormone Luteinizing Hormone Pituitary Gland, Anterior Potassium Prolactin Rats Rats, Sprague-Dawley Receptors, LHRH Secretory Rate Animalia |
| description |
Polyamines play an essential role in tissue growth and differentiation, in body weight increment, in brain organization, and in the molecular mechanisms of hormonal action, intracellular signaling, and cell-to-cell communication. In a previous study, inhibition of their synthesis by α- difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase, during development in female rats, was followed by prolonged high follicle-stimulating hormone (FSH) serum level and a delayed puberty onset. Those changes were relatively independent of body mass and did not impair posterior fertility. The present work studies the mechanisms and site of action of polyamine participation in FSH secretion during development. DFMO was injected in female rats between Days 1 and 9 on alternate days. At 10 days of age, hypothalami from control and DFMO rats were perifused in vitro, and basal and potassium-induced gonadotropin- releasing hormone (GnRH) release were measured. The response to membrane depolarization was altered in DFMO hypothalami. Increased GnRH release in response to a low K + concentration was evidenced. Adenohypophyses of the same treated prepubertal rats were perifused in vitro and the response to GnRH pulses was checked. In DFMO-treated rats, higher FSH release was observed, with no changes in LH or PRL secretion. Finally, pituitary GnRH receptor number in adenohypophyseal membranes from treated and control groups was quantified. A significant reduction in specific binding was evident in hypophyses from DFMO-treated rats when compared with binding in the control group. In summary, DFMO treatment in a critical developmental period in the female rat impacts the immature GnRH neuronal network and immature gonadotropes. A delay in maturation is evidenced by a higher sensitivity to secretagogs in both pituitary glands and hypothalamic explants. These events could explain the prolonged high FSH serum levels and delayed puberty onset seen in this experimental model. |
| title |
α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| title_short |
α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| title_full |
α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| title_fullStr |
α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| title_full_unstemmed |
α-Difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| title_sort |
α-difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat |
| publishDate |
1997 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v215_n2_p192_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v215_n2_p192_Thyssen |
| _version_ |
1768545455053996032 |