AUTHOR=Zhang Yu Ting , Hong Wan Shu , Liu Dong Teng , Qiu Heng Tong , Zhu Yong , Chen Shi Xi 

TITLE=Involvement of Membrane Progestin Receptor Beta (mPRβ/Paqr8) in Sex Pheromone Progestin-Induced Expression of Luteinizing Hormone in the Pituitary of Male Chinese Black Sleeper (Bostrychus Sinensis)

JOURNAL=Frontiers in Endocrinology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2018.00397

DOI=10.3389/fendo.2018.00397

ISSN=1664-2392

ABSTRACT=<p>Our previous studies showed that 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) acted as a sex pheromone to induce reproductive success in Chinese black sleeper (<italic>Bostrychus sinensis</italic>), but its functional mechanism remains unclear. In the present study, we cloned the cDNAs of the gonadotropin subunits (<italic>cg</italic>α<italic>, fsh</italic>β, and <italic>lh</italic>β), and found that, in exposure to 5 nM DHP, transcript levels of <italic>lh</italic>β significantly increased in the pituitary at 6 h post exposure; plasma 11-KT levels increased at 24 h post exposure in mature male fish. In contrast, DHP exposure failed to increase the transcript levels of <italic>lh</italic>β in the pituitary of immature male fish, suggesting that the responsiveness to DHP depends on reproductive status. Interestingly, expression of progestin and adipoQ receptor 8 (<italic>paqr8</italic>, also known as mPRβ) and progesterone receptor membrane component 2 significantly increased in the olfactory rosette of male fish at late meiosis stage following a co-injection of human chorionic gonadotropin (HCG) and luteinizing hormone releasing hormone-A<sub>3</sub> (LHRH-A<sub>3</sub>), while no increases of other progestin receptors were observed. Moreover, Paqr8 protein was localized in the dendritic knobs of the olfactory sensory neurons, which were activated following the <italic>in vivo</italic> exposure to DHP. The DHP-induced expression of <italic>lh</italic>β in pituitary was not inhibited by RU486, an antagonist of nuclear progesterone receptor. Taken together, our results suggested that sex pheromone DHP increased the expression of <italic>lh</italic>β transcript in the pituitary and plasma 11-KT levels of mature male, important for reproduction; and Paqr8 might be involved in responding to sex pheromone DHP in the olfactory rosette of male <italic>B. sinensis</italic>.</p>