A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life.
Testis growth during early life is important for future male fertility and shows acceleration during the first months of life in humans. This acceleration coincides with the peak in gonadotropic hormones in the blood, while the role of hypothalamic factors remains vague. Using neonatal rats to asses...
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Public Library of Science (PLoS)
2014-01-01
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| author | Nikolay N Dygalo Tatjana V Shemenkova Tatjana S Kalinina Galina T Shishkina |
| author_facet | Nikolay N Dygalo Tatjana V Shemenkova Tatjana S Kalinina Galina T Shishkina |
| author_sort | Nikolay N Dygalo |
| collection | DOAJ |
| description | Testis growth during early life is important for future male fertility and shows acceleration during the first months of life in humans. This acceleration coincides with the peak in gonadotropic hormones in the blood, while the role of hypothalamic factors remains vague. Using neonatal rats to assess this issue, we found that day 9 of life is likely critical for testis development in rats. Before this day, testicular growth was proportional to body weight gain, but after that the testes showed accelerated growth. Hypothalamic kisspeptin and its receptor mRNA levels begin to elevate 2 days later, at day 11. A significant increase in the mRNA levels for gonadotropin-releasing hormone (GnRH) receptors in the hypothalamus between days 5 and 7 was followed by a 3-fold decrease in GnRH mRNA levels in this brain region during the next 2 days. Starting from day 9, hypothalamic GnRH mRNA levels increased significantly and positively correlated with accelerated testicular growth. Triptorelin, an agonist of GnRH, at a dose that had no effect on testicular growth during "proportional" period, increased testis weights during the period of accelerated growth. The insensitivity of testicular growth to GnRH during "proportional" period was supported by inability of a 2.5-fold siRNA knockdown of GnRH expression in the hypothalamus of the 7-day-old animals to produce any effect on their testis weights. GnRH receptor blockade with cetrorelix was also without effect on testis weights during "proportional" period but the same doses of this GnRH antagonist significantly inhibited "accelerated" testicular growth. GnRH receptor mRNA levels in the pituitary as well as plasma LH concentrations were higher during "accelerated" period of testicular growth than during "proportional" period. In general, our data defined two distinct periods in rat testicular development that are primarily characterized by different responses to GnRH signaling. |
| format | Article |
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| issn | 1932-6203 |
| language | English |
| publishDate | 2014-01-01 |
| publisher | Public Library of Science (PLoS) |
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| spelling | doaj-art-b9da1d6775d24c5d8db42808e8a2ff212025-08-20T02:14:55ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0194e9300710.1371/journal.pone.0093007A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life.Nikolay N DygaloTatjana V ShemenkovaTatjana S KalininaGalina T ShishkinaTestis growth during early life is important for future male fertility and shows acceleration during the first months of life in humans. This acceleration coincides with the peak in gonadotropic hormones in the blood, while the role of hypothalamic factors remains vague. Using neonatal rats to assess this issue, we found that day 9 of life is likely critical for testis development in rats. Before this day, testicular growth was proportional to body weight gain, but after that the testes showed accelerated growth. Hypothalamic kisspeptin and its receptor mRNA levels begin to elevate 2 days later, at day 11. A significant increase in the mRNA levels for gonadotropin-releasing hormone (GnRH) receptors in the hypothalamus between days 5 and 7 was followed by a 3-fold decrease in GnRH mRNA levels in this brain region during the next 2 days. Starting from day 9, hypothalamic GnRH mRNA levels increased significantly and positively correlated with accelerated testicular growth. Triptorelin, an agonist of GnRH, at a dose that had no effect on testicular growth during "proportional" period, increased testis weights during the period of accelerated growth. The insensitivity of testicular growth to GnRH during "proportional" period was supported by inability of a 2.5-fold siRNA knockdown of GnRH expression in the hypothalamus of the 7-day-old animals to produce any effect on their testis weights. GnRH receptor blockade with cetrorelix was also without effect on testis weights during "proportional" period but the same doses of this GnRH antagonist significantly inhibited "accelerated" testicular growth. GnRH receptor mRNA levels in the pituitary as well as plasma LH concentrations were higher during "accelerated" period of testicular growth than during "proportional" period. In general, our data defined two distinct periods in rat testicular development that are primarily characterized by different responses to GnRH signaling.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0093007&type=printable |
| spellingShingle | Nikolay N Dygalo Tatjana V Shemenkova Tatjana S Kalinina Galina T Shishkina A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. PLoS ONE |
| title | A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. |
| title_full | A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. |
| title_fullStr | A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. |
| title_full_unstemmed | A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. |
| title_short | A critical point of male gonad development: neuroendocrine correlates of accelerated testicular growth in rats during early life. |
| title_sort | critical point of male gonad development neuroendocrine correlates of accelerated testicular growth in rats during early life |
| url | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0093007&type=printable |
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