1. Leptin Stimulates Prolactin mRNA Expression in the Goldfish Pituitary through a Combination of the PI3K/Akt/mTOR, MKK3/6/p38MAPK and MEK1/2/ERK1/2 Signalling Pathways.
- Author
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Aifen Yan, Yanfeng Chen, Shuang Chen, Shuisheng Li, Yong Zhang, Jirong Jia, Hui Yu, Lian Liu, Fang Liu, Chaoqun Hu, Dongsheng Tang, and Ting Chen
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LEPTIN ,PITUITARY hormones ,GOLDFISH ,OSTEICHTHYES ,OSMOREGULATION ,PROLACTIN ,MESSENGER RNA ,CELLULAR signal transduction ,FISHES - Abstract
Leptin actions at the pituitary level have been extensively investigated in mammalian species, but remain insufficiently characterized in lower vertebrates, especially in teleost fish. Prolactin (PRL) is a pituitary hormone of central importance to osmoregulation in fish. Using goldfish as a model, we examined the global and brain-pituitary distribution of a leptin receptor (lepR) and examined the relationship between expression of lepR and major pituitary hormones in different pituitary regions. The effects of recombinant goldfish leptin-AI and leptin-AII on PRL mRNA expression in the pituitary were further analysed, and the mechanisms underlying signal transduction for leptin-induced PRL expression were determined by pharmacological approaches. Our results showed that goldfish lepR is abundantly expressed in the brain-pituitary regions, with highly overlapping PRL transcripts within the pituitary. Recombinant goldfish leptin-AI and leptin-AII proteins could stimulate PRL mRNA expression in dose- and time-dependent manners in the goldfish pituitary, by both intraperitoneal injection and primary cell incubation approaches. Moreover, the PI3K/Akt/mTOR, MKK
3/6 /p38 MAPK, and MEK1/2 /ERK1/2 --but not JAK2/STAT 1, 3 and 5 cascades--were involved in leptin-induced PRL mRNA expression in the goldfish pituitary. [ABSTRACT FROM AUTHOR]- Published
- 2017
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