Hormonal regulation of testosterone production in short-term primary culture of fetal mouse Leydig cells.

Short-term primary culture of Leydig cells were prepared from 18 day old fetal mouse testes. The cells were cultured in a defined medium supplemented with 1% fetal calf serum, EGF and Insulin. The cells rapidly attached to the plastic culture dish. Seventy to eighty percent of the firmly attached cells stained positively for 3 beta-HSD activity and gradually assumed a flattened epitheloid appearance. The functional activity of these cells in terms of testosterone production and hCG-responsiveness was maintained for 2 days. There was a significant effect of plating density. Pre-culture (24 h) of fetal Leydig cells in the presence of 100 mIU hCG desensitized these cells to a subsequent stimulation by hCG. This is the first report of a short-term primary culture of fetal Leydig cells which demonstrates the maintenance of androgenic activity of these cells in vitro.