Multiple Pathways for Cationic Amino Acid Transport in Rat Seminiferous Tubule Cells1

Abstract

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. Our data suggest that l-arginine is taken up by Sertoli cells and peritubular cells, principally via system y(+)L (SLC3A2/SLC7A6) and system y(+) (SLC7A1 and SLC7A2), with system B(0+) making a minor contribution. By contrast, system B(0+), associated with system y(+)L (SLC3A2/SLC7A7 and SLC7A6), made a major contribution to the transport of cationic amino acids in pachytene spermatocytes and early spermatids. Sertoli cells had higher rates of l-arginine transport than the other seminiferous tubule cells. This high efficiency of arginine transport in Sertoli cells and the properties of the y(+)L system predominating in these cells strongly suggest that Sertoli cells play a key role in supplying germ cells with l-arginine and other cationic amino acids. Furthermore, whereas cytokines induce nitric oxide (NO) production in peritubular and Sertoli cells, little or no upregulation of arginine transport by cytokines was observed in these cells. Thus, NO synthesis does not depend on the stimulation of arginine transport in these somatic tubular cells.

Impact of Ocean Warming and Acidification on Symbiosis Establishment and Gene Expression Profiles in Recruits of Reef Coral Acropora intermedia

“…Tret1 codes for a “PREDICTED: solute carrier family 2, facilitated glucose transporter member 8-like” protein, while SLC7A1 and SLC7A2 code for “PREDICTED: cationic amino acid transporter 2-like isoform X1” and “PREDICTED: cationic amino acid transporter 2-like isoform,” respectively. These two amino acid transporters translocate L-arginine produced by symbiont algae from the symbiont to the coral host ( Ferrier, 1994 ; Cérec et al, 2007 ), although glucose is the major photosynthetic product translocated from symbionts to coral host ( Hillyer et al, 2017a ). The onset of symbiosis was not successfully established under heat stress, suggesting a low production of glucose and amino acids.…”

“…Each gene box is equally divided into four pieces (A, C, H, and H+C), sequentially representing ATAC, ATHC, HTAC, and HTHC treatment, respectively. two amino acid transporters translocate L-arginine produced by symbiont algae from the symbiont to the coral host (Ferrier, 1994;Cérec et al, 2007), although glucose is the major photosynthetic product translocated from symbionts to coral host (Hillyer et al, 2017a). The onset of symbiosis was not successfully established under heat stress, suggesting a low production of glucose and amino acids.…”

Seasonal differences in the testicular transcriptome profile of free-living European beavers (Castor fiber L.) determined by the RNA-Seq method

“…The SLC7A1 gene mediates the transport of cationic amino acids across cell membrane. It has been reported that rat Sertoli cells express SLC7A1 which relies on the NA+-independent transport system to deliver arginine or other cationic amino acids to germ cells [47]. The KCNMB2 gene is a calcium-gated potassium channel that has been described in various mammalian endocrine cells, including human and hamster testicular Leydig cells [48].…”

Novel male-biased expression in paralogs of the aphid slimfast nutrient amino acid transporter expansion

“…One possible role for these male-biased paralogs that we cannot predict from female expression profiles is a role in male reproduction, such as spermatogenesis. Although slimfast has never been implicated in spermatogenesis, related mammalian transporters ( SLC7A1 and SLC7A2 ) deliver L-Arginine to rat seminiferous tubule cells [37], where spermatogeneis begins. Thus, divergence of some slimfast paralogs to fill a male reproductive role is plausible.…”