Furlong T J, Posen S
Department of Medicine, Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
Am J Physiol. 1990 Feb;258(2 Pt 2):F321-7. doi: 10.1152/ajprenal.1990.258.2.F321.
Brush-border membrane vesicles (BBMV) were prepared from rat and human renal cortical tissue by magnesium aggregation and differential centrifugation, and the uptake of L-cystine, L-cysteine, and L-cysteine-D-penicillamine were assessed by a rapid-filtration technique. L-Cystine uptake was relatively sodium independent and associated with membrane binding. Sodium-stimulated uptake was sensitive to a cation but not anion diffusion potential. Both sodium-independent and sodium-stimulated uptake rates were inhibited by the cationic L-amino acids and by some neutral L-amino acids. The uptake rates of L-cysteine and L-cysteine-D-penicillamine were more sodium dependent, and sodium-stimulated uptake rates were more sensitive to cation and anion diffusion potentials. Neither the sodium-independent nor the sodium-stimulated uptake rates of L-cysteine or L-cysteine-D-penicillamine were inhibited by the cationic L-amino acids. L-Cysteine-D-penicillamine showed relatively little membrane binding. It is concluded that L-cystine is transported into renal cortical BBMV by pathways distinct from those concerned with the transport of L-cysteine and L-cysteine-D-penicillamine, and it is postulated that these differences may account for some of the effects of D-penicillamine in cystinuria.
通过镁聚集和差速离心法从大鼠和人类肾皮质组织中制备刷状缘膜囊泡（BBMV），并采用快速过滤技术评估L-胱氨酸、L-半胱氨酸和L-半胱氨酸-D-青霉胺的摄取情况。L-胱氨酸摄取相对不依赖于钠，且与膜结合有关。钠刺激的摄取对阳离子扩散电位敏感，但对阴离子扩散电位不敏感。阳离子L-氨基酸和一些中性L-氨基酸均抑制钠非依赖性和钠刺激的摄取速率。L-半胱氨酸和L-半胱氨酸-D-青霉胺的摄取速率对钠的依赖性更强，且钠刺激的摄取速率对阳离子和阴离子扩散电位更敏感。阳离子L-氨基酸既不抑制L-半胱氨酸的钠非依赖性摄取速率，也不抑制其钠刺激的摄取速率，对L-半胱氨酸-D-青霉胺也是如此。L-半胱氨酸-D-青霉胺显示出相对较少的膜结合。结论是，L-胱氨酸通过与L-半胱氨酸和L-半胱氨酸-D-青霉胺运输相关途径不同的途径转运至肾皮质BBMV中，据推测，这些差异可能是青霉胺在胱氨酸尿症中某些作用的原因。
