The Na+/I- symporter (NIS) mediates active iodide uptake in the intestine

NICOLA, JP; BASQUIN, C; PORTULANO, C; REYNA-NEYRA, A; PARODER, M; CARRASCO, N

AMER PHYSIOLOGICAL SOC

Lugar: Bethesda; Año: 2009 vol. 296 p. 654 - 654

Absorption of dietary iodide, presumably in the small intestine, is the first step in iodide(I-) utilization. From the bloodstream, I- is actively taken up via the Na+/I- symporter (NIS) in the thyroid for thyroid hormone biosynthesis and in such other tissues as lactating breast,which supplies I- to the newborn in the milk. The molecular basis for intestinal I- absorption is unknown. We sought to determine whether I- is actively accumulated by enterocytes and, if so, whether this process is mediated by NIS and regulated by I- itself. NIS expression waslocalized exclusively at the apical surface of rat and mouse enterocytes. In vivo intestine-to-blood transport of pertechnetate, a NIS substrate, was sensitive to the NIS inhibitorperchlorate. Brush border membrane vesicles accumulated I- in a sodium-dependent,perchlorate-sensitive manner with kinetic parameters similar to those of thyroid cells. NIS was expressed in intestinal epithelial cell line 6 (