title: Reduced somatostatin in hypothalamus of young male mouse increases local but not circulatory GH.
abstract: The release of growth hormone (GH) from the pituitary gland is primarily inhibited by somatostatin (SRIF) from the hypothalamus via interactions with five types of SRIF receptors (SSTRs). However, the inhibition mechanism of SRIF on GH has not been fully examined. In this study, we repressed the hypothalamic SRIF in young male mice by stereotaxic injection of the lentiviral-shRNA against SRIF to investigate the role of hypothalamic SRIF on hormone secretion in the GH/IGF-1 axis. We found that the reduction of SRIF in hypothalamus was associated with an increase in the protein, but not the mRNA level, of the GH in the pituitary where SSTR 2 and SSTR 5 act importantly. Interestingly, the level of blood circulatory SRIF, GH, IGF-1 and the body weight were not significantly influenced by the downregulation of hypothalamic SRIF. Our findings provide insights into the mechanisms underlying the inhibition of SRIF on GH secretion.
authors.affiliation: Department of Biochemistry, Veterinary College, Jilin University, No 5333 Xi'an Road, Changchun 130062, People's Republic of China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Hao
authors.forename: Mingtang
authors.initials: M
authors.lastname: Li
authors.forename: Jianwei
authors.initials: J
authors.lastname: Dai
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Liu
authors.forename: Songcai
authors.initials: S
authors.lastname: Liu
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D055785:Gene Knockdown Techniques; D013006:Growth Hormone / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D013004:Somatostatin / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D013004:Somatostatin; D013006:Growth Hormone