Growth Hormone (GH)-Releasing Factor Does Not Regulate GH Release or GH mRNA Levels in GH3Cells*

Abstract
Growth hormone releasing factor (GRF) regulates both growth hormone [GH] production and GH [messenger] mRNA levels in primary cultures of rat pituitary cells. Investigations were carried out to ascertain the ability of GRF to regulate GH production or mRNA levels in a clonal strain of rat putuitary tumor (GH3) cells. Incubation of the cells with GRF at 1-1000 nM for 4 h-10 days did not result in a stimulation of GH or prolactin [PRI] production, nor did it effect the cytoplasmic levels of the corresponding mRNA. The lack of response to GRF was not affected by dexamethasone triiodothyronine [T3] or serum. Apparently, GH3 cells do not provide a useful model system for studies of the mechanism(S) of action or GRF on either GH release or GH gene expression.

This publication has 12 references indexed in Scilit: