Nerve growth factor and glucocorticoids regulate phenotypic expression in cultured chromaffin cells from adult rhesus monkeys.

Adrenal chromaffin cells and sympathetic neurons are both derivatives of the neural crest. Despite their morphological and functional differences, chromaffin cells retain some developmental plasticity and if treated with Nerve Growth Factor (NGF), can express certain characteristics of sympathetic neurons. However, there is some age and species variability in the response of chromaffin cells to NGF: in general chromaffin cells from adult animals are not considered to be dependent on NGF for survival, and chromaffin cells from adults of several species fail to respond to NGF in vitro by growing neurites. This is in contrast to the dramatic effects of NGF on chromaffin cells from perinatal rats. We have examined the requirements of chromaffin cells from adult rhesus monkeys to survive, to proliferate, and to express a neuronal morphology in vitro. NGF greatly enhances the proportion of rhesus chromaffin cells that form neurites and the length of the neurites that are formed, but the conversion to a neuronal phenotype is more limited than in chromaffin cells cultured from young rats. NGF also enhances rhesus chromaffin cell survival, but fails to stimulate their proliferation, in contrast to its effect on perinatal rat cells [18]. Glucocorticoid hormones (GCs) specifically antagonize the effects of NGF on neuritic outgrowth while promoting chromaffin cell survival. Thus adrenal chromaffin cells from rhesus monkeys retain a degree of developmental plasticity even in the adult animal.