Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats
Polyamines, putrescine (PUT), spermidine (SPD), spermine (SPM), and agmatine (AGM), are polycationic amines related to multiple cell functions found in high concentrations during the development of hypothalamus and pituitary. In previous works, we demonstrated that α-difluoromethylornithine (DFMO),...
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2002
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v227_n4_p276_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v227_n4_p276_Thyssen |
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paper:paper_00379727_v227_n4_p276_Thyssen2023-06-08T15:02:25Z Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats Adenohypophysis GnRH Gonadotropins Hypothalamus Polyamines agmatine eflornithine follitropin gonadorelin gonadotropin luteinizing hormone polyamine putrescine spermidine spermine adenohypophysis animal cell animal experiment article cell culture controlled study development female hormone release hypothalamus nonhuman radioimmunoassay sex differentiation Animals Cells, Cultured Eflornithine Female Gonadotropin-Releasing Hormone Gonadotropins Pituitary Gland Polyamines Pregnancy Radioimmunoassay Rats Rats, Sprague-Dawley Animalia Polyamines, putrescine (PUT), spermidine (SPD), spermine (SPM), and agmatine (AGM), are polycationic amines related to multiple cell functions found in high concentrations during the development of hypothalamus and pituitary. In previous works, we demonstrated that α-difluoromethylornithine (DFMO), an inhibitor of polyamines biosynthesis, induced a delay in puberty of female rats, accompanied by high, sustained follicle-stimulating hormone (FSH) levels during the infantile period. Also, DFMO treatment induced changes in polyamine concentration both in hypothalamus and pituitary of rats, mainly a decrease of PUT and SPD, an increase in SPM, and no change in AGM. In the present work, we investigated the direct effects of polyamines on the secretion of hypothalamic GnRH and pituitary gonadotropins in 6- and 15-day-old female rats. In 6-day-old animals, in vitro incubations with PUT, SPD, and AGM of hypothalami or anterior pituitaries were able to inhibit GnRH, FSH, and leutinizing hormone (LH) secretion, respectively. SPM showed a nonspecific transient inhibitory effect on FSH. When challenged with either high K+ (hypothami) or GnRH (pituitaries), the tissues incubated in the presence of polyamines showed no differences when compared with their controls. No effects of polyamines in 15-day-old rats in either tissue were observed. Pituitary cell cultures of 6-day-old animals incubated with DFMO for 4 days showed a significant increase in FSH, but not in LH. We conclude that high PUT, SPD, and AGM levels during the first 10 days of life are important for the development of the hypothalamic-hypophyseal unit, probably related to an inhibitory effect on GnRH and gonadotropins. Therefore, polyamine participation, especially PUT and SPD, is of importance in the regulation of GnRH and gonadotropin secretion in the neonatal and infantile periods, critical stages in the establishment of sexual differentiation. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v227_n4_p276_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v227_n4_p276_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 |
Adenohypophysis GnRH Gonadotropins Hypothalamus Polyamines agmatine eflornithine follitropin gonadorelin gonadotropin luteinizing hormone polyamine putrescine spermidine spermine adenohypophysis animal cell animal experiment article cell culture controlled study development female hormone release hypothalamus nonhuman radioimmunoassay sex differentiation Animals Cells, Cultured Eflornithine Female Gonadotropin-Releasing Hormone Gonadotropins Pituitary Gland Polyamines Pregnancy Radioimmunoassay Rats Rats, Sprague-Dawley Animalia |
| spellingShingle |
Adenohypophysis GnRH Gonadotropins Hypothalamus Polyamines agmatine eflornithine follitropin gonadorelin gonadotropin luteinizing hormone polyamine putrescine spermidine spermine adenohypophysis animal cell animal experiment article cell culture controlled study development female hormone release hypothalamus nonhuman radioimmunoassay sex differentiation Animals Cells, Cultured Eflornithine Female Gonadotropin-Releasing Hormone Gonadotropins Pituitary Gland Polyamines Pregnancy Radioimmunoassay Rats Rats, Sprague-Dawley Animalia Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| topic_facet |
Adenohypophysis GnRH Gonadotropins Hypothalamus Polyamines agmatine eflornithine follitropin gonadorelin gonadotropin luteinizing hormone polyamine putrescine spermidine spermine adenohypophysis animal cell animal experiment article cell culture controlled study development female hormone release hypothalamus nonhuman radioimmunoassay sex differentiation Animals Cells, Cultured Eflornithine Female Gonadotropin-Releasing Hormone Gonadotropins Pituitary Gland Polyamines Pregnancy Radioimmunoassay Rats Rats, Sprague-Dawley Animalia |
| description |
Polyamines, putrescine (PUT), spermidine (SPD), spermine (SPM), and agmatine (AGM), are polycationic amines related to multiple cell functions found in high concentrations during the development of hypothalamus and pituitary. In previous works, we demonstrated that α-difluoromethylornithine (DFMO), an inhibitor of polyamines biosynthesis, induced a delay in puberty of female rats, accompanied by high, sustained follicle-stimulating hormone (FSH) levels during the infantile period. Also, DFMO treatment induced changes in polyamine concentration both in hypothalamus and pituitary of rats, mainly a decrease of PUT and SPD, an increase in SPM, and no change in AGM. In the present work, we investigated the direct effects of polyamines on the secretion of hypothalamic GnRH and pituitary gonadotropins in 6- and 15-day-old female rats. In 6-day-old animals, in vitro incubations with PUT, SPD, and AGM of hypothalami or anterior pituitaries were able to inhibit GnRH, FSH, and leutinizing hormone (LH) secretion, respectively. SPM showed a nonspecific transient inhibitory effect on FSH. When challenged with either high K+ (hypothami) or GnRH (pituitaries), the tissues incubated in the presence of polyamines showed no differences when compared with their controls. No effects of polyamines in 15-day-old rats in either tissue were observed. Pituitary cell cultures of 6-day-old animals incubated with DFMO for 4 days showed a significant increase in FSH, but not in LH. We conclude that high PUT, SPD, and AGM levels during the first 10 days of life are important for the development of the hypothalamic-hypophyseal unit, probably related to an inhibitory effect on GnRH and gonadotropins. Therefore, polyamine participation, especially PUT and SPD, is of importance in the regulation of GnRH and gonadotropin secretion in the neonatal and infantile periods, critical stages in the establishment of sexual differentiation. |
| title |
Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| title_short |
Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| title_full |
Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| title_fullStr |
Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| title_full_unstemmed |
Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| title_sort |
effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats |
| publishDate |
2002 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00379727_v227_n4_p276_Thyssen http://hdl.handle.net/20.500.12110/paper_00379727_v227_n4_p276_Thyssen |
| _version_ |
1768544948144046080 |