Growth hormone and insulin-like growth factor-I do not activate identical genes in normal human osteoblasts

In this study, we have examined the expression of mRNAs induced by growth hormone (GH) and insulin-like growth factor-I (IGF-I) in normal human osteoblasts using the differential display PCR method. Cells were incubated in the presence of 10(-7)M GH or IGF-I, RNA isolated and reverse-transcribed using an oligonucleotide primer, T11AC, anchored to the polyadenylate tail of a subset of mRNAs. The cDNA was then amplified using T11AC and an arbitrary 10-mer in the presence of [alpha-35S] dCTP. The PCR products were subsequently separated on a 6% DNA sequencing gel. The obtained patterns demonstrate that most, but not all, mRNAs induced by GH or IGF-I are identical. We conclude that GH and IGF-I do not induce expression of identical mRNAs in human osteoblasts. Our results support the dual effector theory of growth hormone action.