Transplantation and subsequent recovery of small amounts of isolated Leydig cells.

A technique is described for transplantation of a few million Leydig cells in a gelatin sponge. Within 7 days after subcutaneous transplantation in the neck, a spongeous tissue develops within the gelatin matrix. This tissue contains Leydig cells, fibroblasts, and blood vessels. Isolated Leydig cells were recovered after collagenase dispersion of this tissue. Steroid production by these isolated cells can be stimulated by LH, but the response is less than with fresh Leydig cells isolated directly from testicular tissue. The biochemical properties of Leydig cells devoid of surrounding Sertoli cells can be applied to long-term studies.