Maturation of steroidogenic cells: a target for IGF-I.

Using primary culture of steroidogenic cells in vitro, in serum-free chemically defined medium, strong evidence has been provided for actions of IGF-I on the differentiation of immature Leydig cells and on the maintenance of a differentiated function of mature adrenocortical cells. These data point to the steroidogenic cells as a target for IGF-I action. They also add further evidence for a role of IGF-I in the differentiation process. These actions can be of importance in normal physiological situations as well as in abnormal conditions where IGF-I is decreased, such as hypopituitarism and malnutrition.