SFEBES2023 Poster Presentations Neuroendocrinology and Pituitary (74 abstracts)
Analyses of the effects of adrenomedullin on the gonadotrophin-releasing hormone pulse generator and luteinising hormone pulses
Yukina Oshimo 1 , Marimo Sato 1 , Yuri Kondo 2 , Natsuho Hayashi 2 , Wenhao Cui 1 , Sho Nakamura 2 , Shuichi Matsuyama 2 , Satoshi Ohkura 2 , Fumie Magata 1 & Fuko Matsuda 1
1the Univ. of Tokyo, Tokyo, Japan. 2Nagoya Univ., Nagoya, Japan
The pulse mode of gonadotrophin-releasing hormone (GnRH) release from the hypothalamus and following luteinising hormone (LH) pulses from the pituitary induce follicular development in female animals. Kisspeptin neurons in the hypothalamic arcuate nucleus (ARC) are suggested to be the GnRH pulse generator. Adrenomedullin (AM) is a secretory peptide expressed in various tissues, including the hypothalamic paraventricular nucleus, but its functions in the central regulation of reproduction remain unclear. We previously reported that an injection of AM into the lateral ventricle (LV) suppressed LH pulses in ovariectomised and estradiol-treated female rats without affecting the number of kisspeptin neurons in the ARC. In the present study, we aimed to analyse the effect of AM on GnRH pulse generator activity and LH pulses using goats, whose activity of the GnRH pulse generator can be monitored in vivo. AM (0 or 5 nmol) was injected into the LV of ovariectomised Shiba goats while recording the multiple unit activity (MUA) in the ARC area and taking blood samples serially for 2 h of pre- and post-injection. And then, plasma LH concentrations were measured by radioimmunoassay to detect LH pulses. AM administration did not change the frequency of MUA volleys (pre vs post). On the other hand, AM decreased the rate of change of mean and baseline LH concentrations. These results indicated the suppressive effect of AM on pulsatile LH secretion in ruminants as with rodents. It is also suggested that the suppressive effect is not mediated by ARC kisspeptin neurons, the GnRH pulse generator.
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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