WCRB2014 POSTER PRESENTATIONS (1) (335 abstracts)
1Azabu University, Sagamihara, Japan; 2Nagoya University, Nagoya, Japan; 3The University of Tokyo, Bunkyo-ku, Japan.
Introduction: Kisspeptin, encoded by Kiss1, is a neuropeptide that directly regulates GnRH secretion from the hypothalamus. The present study aimed to examine a relationship between the circulating gonadotropin levels and follicle development using the Kiss1 knockout (Kiss1 KO) adult female rats.
Materials and methods: Kiss1 KO and WT animals were obtained by mating of Kiss1+/− males and females. The plasma was daily collected to determine gonadotropin levels for 4 days. The follicle development was examined by morphometric analysis for serial ovarian sections, and reproduction-related gene expressions were determined by in situ hybridization and real-time PCR.
Results and discussion: While plasma LH and FSH levels of the WT rats were fluctuated with a peak at proestrous afternoon, those of Kiss1 KO rats were undetectable throughout the consecutive 4 days. Kiss1 KO ovaries were smaller than WT ovaries, and secondary interstitium were predominantly observed in the sections. Although some antral follicles attained the maximum diameter nearly 300 μm, most of follicles sized more than 200 μm showed signs of atresia in Kiss1 KO ovaries. The secondary interstitium and theca cells expressed LH receptor (LHR) mRNA in Kiss1 KO ovaries. The granulosa cells in the antral follicles expressed FSHR mRNA, however, no follicles attained developmental stages where the granulosa cells expressed LHR mRNA. Since gene quantification suggested that Kiss1 KO ovaries expressed more mRNAs encoding inhibin α and inhibin/activin βA than WT ovaries, such paracrine regulators could develop follicles to antral follicle stage without gonadotropins.