Skip to Content
Merck
  • Prenatal androgen excess enhances stimulation of the GNRH pulse in pubertal female rats.

Prenatal androgen excess enhances stimulation of the GNRH pulse in pubertal female rats.

The Journal of endocrinology (2014-05-16)
Xiaonan Yan, Chun Yuan, Nannan Zhao, Yugui Cui, Jiayin Liu
ABSTRACT

In adolescent girls with polycystic ovary syndrome (PCOS), neuroendocrine derangements manifest after the onset of puberty, characterized by rapid LH pulse frequency. The early mechanism underlying the pubertal regulation of the GNRH/LH pulsatile release in adolescents with PCOS remains uncertain. To determine the effects of prenatal androgen exposure on the activation of GNRH neurons and generation of LH pulse at puberty, we administrated 5α-dihydrotestosterone to pregnant rats and observed serum LH levels and expression of hypothalamic genes in female offspring from postnatal 4 to 8 weeks. The 6-week-old prenatally androgenized (PNA) female rats exhibited an increase in LH pulse frequency. The hypothalamic expression of neurokinin B (Nkb (Tac2)) and Lepr mRNA levels in PNA rats increased remarkably before puberty and remained high during puberty, whereas elevated Kiss1 mRNA levels were detected only after the onset of puberty. Exogenous kisspeptin, NK3R agonist, and leptin triggered tonic stimulation of GNRH neurons and increased LH secretion in 6-week-old PNA rats. Leptin upregulated Kiss1 mRNA levels in the hypothalamus of pubertal PNA rats; however, pretreatment with a kisspeptin antagonist failed to suppress the elevated serum LH stimulated by leptin, indicating that the stimulatory effects of leptin may be conveyed indirectly to GNRH neurons via other neural components within the GNRH neuronal network, rather than through the kisspeptin-GPR54 pathway. These findings validate the hypotheses that NKB and leptin play an essential role in the activation of GNRH neurons and initiation of increased LH pulse frequency in PNA female rats at puberty and that kisspeptin may coordinate their stimulatory effects on LH release.

MATERIALS
Product Number
Brand
Product Description

Supelco
Benzyl benzoate, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Benzyl benzoate, United States Pharmacopeia (USP) Reference Standard
Supelco
Benzyl benzoate, analytical standard
Sigma-Aldrich
Benzyl benzoate, ≥99%, FCC, FG
Sigma-Aldrich
Benzyl benzoate, tested according to Ph. Eur.
Sigma-Aldrich
Benzyl benzoate, meets USP testing specifications
Sigma-Aldrich
Benzyl benzoate, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Benzyl benzoate, natural, ≥99%, FG