SFEBES2018 Oral Communications Neuroendocrinology and Reproduction (6 abstracts)
Imperial College London, London, UK.
Background: Kisspeptin stimulates gonadotropin secretion indirectly by stimulation of hypothalamic GnRH neurons. Kisspeptin and kisspeptin receptor, a G-protein coupled receptor (GPCR), are also expressed in the human ovary, but their direct actions on ovary, if any, are unclear.
Objectives: To examine the direct actions of kisspeptin on granulosa lutein cells (GL cells) and the role of kisspeptin in steroidogenesis.
Materials and methods: GL cells were isolated from follicular fluid collected at oocyte retrieval for IVF. Cells were treated in vitro with kisspeptin-10, hCG or a combination of both and then lysed for extraction of RNA, protein, or for measurement of IP1, a marker of phospholipase C activation. Western immunoblotting was used to detect phospho-ERK and phospho-AKT, and an IP1 accumulation assay was carried out, all of which are indicators of activation of receptor Gq activation and signalling.
Results: Treatment in vitro with kisspeptin-10 50 nM for 15 min increased phospho-ERK (2-fold increase, n=9, P<0.05) in GL cells. There was a non-significant increase in phospho-AKT (2-fold, n=7, P=0.1). Kisspeptin treatment for one hour resulted accumulation of IP1 (2.5 fold increase, n=8, P<0.05). Interestingly we detected activation of these Gq signalling pathways in samples from 70% of women, suggesting that kisspeptin receptor is active in the ovaries of some but not all women.
Conclusion: This is the first study examining direct effects of kisspeptin in human granulosa lutein cells. In vitro treatment with kisspeptin activates intracellular signalling, suggesting that it may play a direct role in regulation of ovarian function.