Studies on renal adaptation to altered dietary amino acid intake: reduced renal cortex taurine content increases the Vmax of taurine uptake by brush border membrane vesicles

Research paper by Russell W. Chesney, Naomi Gusowski, Shermine Dabbagh

Indexed on: 01 Mar '87Published on: 01 Mar '87Published in: Pediatric Nephrology


Rats were placed on a normal taurine diet (NTD), low taurine diet (LTD) or a high taurine diet (HTD) for 14 days. β-Alanine was fed to half of the animals in each group and resulted in a lowered renal cortex taurine content. Brush border membrane vesicle (BBMV) uptake of taurine was higher after β-alanine feeding and was associated with an increase in Vmax of uptake. β-Alanine feeding to HTD animals also altered the Km of uptake, possibly since the load of sulfur amino acids (6% of diet) was high. As a control, glycine (3%) feeding for 8 days along with each diet did not alter the plasma or renal cortex content; BBMV uptake as well as Km and Vmax of taurine accumulation were minimally altered. Accordingly, ingestion of a non-sulfur-containing α-amino acid did not change β-amino acid transport. This study provides evidence that whole body taurine homeostasis is maintained in the presence of a taurine-depleting agent (β-alanine feeding) by an increase in the number of Na+-taurine uptake sites.