Renal Na⁺-glucose cotransporters

Abstract

In humans, the kidneys filter approximately 180 g of D-glucose from plasma each day, and this is normally reabsorbed in the proximal tubules. Although the mechanism of reabsorption is well understood, Na(+)-glucose cotransport across the brush-border membrane and facilitated diffusion across the basolateral membrane, questions remain about the identity of the genes responsible for cotransport across the brush border. Genetic studies suggest that two different genes regulate Na(+)-glucose cotransport, and there is evidence from animal studies to suggest that the major bulk of sugar is reabsorbed in the convoluted proximal tubule by a low-affinity, high-capacity transporter and that the remainder is absorbed in the straight proximal tubule by a high-affinity, low-capacity transporter. There are at least three different candidates for these human renal Na(+)-glucose cotransporters. This review will focus on the structure-function relationships of these three transporters, SGLT1, SGLT2, and SGLT3.

Acute effects of glucose and insulin on vascular endothelium

“…As we made comparable observations using D-galactose instead of D-glucose we were able to exclude other members of this SGLT family (SGLT-2 and SGLT-3), since SGLT-1 does not discriminate between D-glucose and D-galactose, while neither SGLT-2 nor SGLT-3 transport D-galactose efficiently (K m >20 mmol/l) [31].…”

“…2d). The transporter isoforms SGLT-1 and GLUT1 have been shown to transport D-galactose as efficiently as D-glucose [30,31]. Accordingly, the effect of D-galactose on endothelial NO release (E max =4.1±0.4 nmol/l, 4.2±0.3 min, n=5) (Fig.…”

Characterisation of glucose transporters in the intact coronary artery endothelium in rats: GLUT-2 upregulated by long-term hyperglycaemia

“…In addition to the GLUT isoforms that we studied, there are another seven known isoforms (GLUT-6 to 12) [9], at least two other isoforms of SGLT [55], and the proton-myoinositol symporter [9]. Antibodies to some of these transporters became available after this study was completed, and for this reason we have not examined their role in the vascular endothelial cell.…”

Functional characterization of a H+/nucleoside co‐transporter (CaCNT) from Candida albicans, a fungal member of the concentrative nucleoside transporter (CNT) family of membrane proteins

“…the melibiose transporter (MelB) of E. coli mediates uphill transport of melibiose coupled to Na + or H + (Botfield et al, 1990), while that of Klebsiella pneumoniae couples sugar transport to H + and Li + (Hama et al, 1992). Similarly, mammalian SGLT1 and SGLT3 can utilize H + or Li + in addition to Na + as the driving force for sugar transport, whereas SGLT2 is Na + -specific (Wright, 2001).…”