Multiple pathways for cationic amino acid transport in rat seminiferous tubule cells.

Arginine and ornithine are known to be important for various biological processes in the testis, but the delivery of extracellular cationic amino acids to the seminiferous tubule cells remains poorly understood. We investigated the activity and expression of cationic amino acid transporters in isolated rat Sertoli cells, peritubular cells, pachytene spermatocytes, and early spermatids. We assessed the l-arginine uptake kinetics, Na(+) dependence of transport, profiles of cis inhibition of uptake by cationic and neutral amino acids, and sensitivity to trans stimulation of cationic amino acid transporters, and studied the expression of the genes encoding them by RT-PCR.