Upregulation of leptin receptor gene expression in the anterior pituitary of human growth hormone-releasing hormone transgenic mice.
The recently cloned leptin receptor (OB-R) is expressed in many tissues, including the anterior pituitary. It is not known whether OB-R gene expression is regulated by pituitary hormones. In the present study, we detected the long isoform of OB-R (OB-R(L)) in the anterior pituitary of normal mice using RT-PCR, but were unable to detect the short isoform (OB-R(S)). In human growth hormone-releasing hormone (hGHRH) transgenic mice, we discovered a significant increase in OB-R(L) mRNA levels in the anterior pituitary as compared to controls, and OB-R(S) gene expression was detectable. In contrast to the pituitary, there were no significant changes in OB-R gene expression for either isoform in the hypothalamus of hGHRH mice. The dramatic increase in the gene expression of OB-R(L) in the anterior pituitary of hGHRH transgenic mice was confirmed by RNase protection assay. This is the first study to demonstrate that OB-R gene expression in the anterior pituitary gland is increased by GH and/or GHRH.
Cai
A
A
Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, Lexington 40536, USA.
Hyde
J F
JF
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D019382:Human Growth Hormone / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D015854:Up-Regulation
D002352:Carrier Proteins; C515448:LEPR protein, human; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; C515447:leptin receptor, mouse; D019382:Human Growth Hormone