The growth hormone-prolactin relationship: a neglected issue.

During embryogenesis, the growth hormone-secreting cells (somatotrophs) and the prolactin-secreting cells (lactotrophs) develop from a common progenitor cell (somatomammotroph). Postnatally, in situations when one of these two hormones is oversecreted, often the second hormone is, too. The question posed is whether the increased secretion of growth hormone together with that of prolactin over long periods of time is a risk factor for malignancy.