11. Testicular and epididymal function. Effects of isolation and purification procedures on the viability and properties of testis Leydig cells.

The effect of the isolation and purification procedures used to obtain mouse and rat Leydig cells on their viability and steroidgenic properties has been investigated. It was found that mechanical dispersion of rat testes prior to collagenase dispersion had a deleterious effect on the steroidogenic capacity of the cells. Omission of the mechanical disruption and separation of the collagenase-dispersed cells on Percoll gradients yielded 3 bands of cells. Band III (density 1.070 g/ml) contained highly pure viable Leydig cells of high steroidogenic capacity. Diaphorase histochemistry (but not trypan blue exclusion) revealed that bands I and II contained high amounts of damaged Leydig cells. These results are discussed in relation to the previously reported heterogeneity of Leydig cells. Both mouse and rat Leydig cells (band III) in monolayer culture maintained their responsiveness to LH for several days. The rat (but not mouse) Leydig cells contained LHRH receptors and responded to LHRH in a biphasic manner: initially a stimulation of both basal and LH increased steroidogenesis occurred which after 24 h became inhibitory.