Expression of Growth Hormone Receptor Gene During 3T3-L1 Differentiation / 대한소아내분비학회지

ABSTRACT

PURPOSE: Growth hormone(GH) produces a variety of effects in adipose tissue via GHRs on the cell membrane. In mouse, alternative splicing of the nascent transcript from the GHR gene produces two major transcriptsGHR mRNA and GHR binding protein(GHBP) mRNA. These two transcripts share the common extracellular ligand-binding domain, but differ in the C-terminal sequence. Since GHR plays an important role in mediating the actions of GH in adipose metabolism, I initiated these studies to examine GHR gene expression during mouse 3T3-Ll preadipocyte-adipocyte differentiation. METHODS: GHR and GHBP transcripts were detected by RNase protection assay (RPA) using the antisense riboprobes complementary either to the specific sequence of the GHR or to the sequence shared by both GHR and GHBP mRNAs. RNA prepared from 3T3-L1 cells at day 0(preadipocytes) and day 7(adipocytes) after treatment with actinomycin D was analyzed by RPA. RESULTS: After stimulation of differentiation, mRNA abundance increased 25-fold and reached a maximal level by day 7 of adipogenesis. The GHR mRNAGHBP mRNA ratio was 1.3+/-.15 and remained unchanged during differentiation. The decay rate for both mRNAs, estimated by treating the cells with actinomycin D, was approximately 24 hours and showed no significant difference between preadipocytes and adipocytes. CONCLUSION: GHR gene expression is upregulated during preadipocyte-adipocyte differentiation.