Puberty and sexual maturation in hemidecorticate female rats.
The onset of puberty and sexual maturation were studied in female rats that had been hemidecorticated (HD) during the neonatal period (1-3 days old). Hemidecorticate and control rats submitted to photostimulation (14 h light: 10 h dark) had earlier and better synchronized vaginal opening (VO) than rats raised under natural light (12 h light: 12 h dark). HD rats maintained under 14 h light: 10 h dark had vaginal opening 4-5 days earlier than their controls under the same light conditions. Peaks of plasma gonadotrophin (LH) were observed in hemidecorticate animals 10 days (30th day of life) earlier than in the controls (40th day). These LH peaks were preceded by higher adenohypophyseal and uterine weights at 25 and 30 days of age. The estrous cycles observed in adult rats that were hemidecorticated during the neonatal period were similar to that of intact rats. These results suggest that hemidecortication induces early puberty. This effect could be due to accelerated maturation of the ovaries probably due to the unrestricted activity of the medial basal hypothalamus, which in turn might activate the hypothalamic mechanisms that trigger puberty.
D000818:Animals; D002541:Cerebral Decortication; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D008027:Light; D007986:Luteinizing Hormone / Q000378:metabolism; D009929:Organ Size; D010053:Ovary / Q000033:anatomy & histology / Q000254:growth & development; D010903:Pituitary Gland, Anterior / Q000033:anatomy & histology; D011247:Pregnancy; D051381:Rats; D012741:Sexual Maturation
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone