Growth hormone is mitogenic for fetal mouse osteoblasts but not for undifferentiated bone cells

More evidence has recently been obtained indicating that growth hormone (GH) has a direct effect on bone. However, it is not clear which cell type reacts to the hormone. The present study used osteoblast-like cells derived from sequentially digested fetal mouse calvaria. Separately cultured tractions resulted in populations enriched in cells with a more or a less differentiated phenotype. The results showed that GH acts on the cells released last, i.e. those with more characteristics of the osteoblast. In these cells, GH induced strong mitogenic activity. Prolactin was not active.