Hajjar J J, Fucci J C, Rowe W A, Tomicic T K
Proc Soc Exp Biol Med. 1987 Apr;184(4):403-9. doi: 10.3181/00379727-184-42493.
Vanadate has been reported to inhibit (Na+ + K+)-ATPase of many cells and in some systems to stimulate adenylate cyclase. Since intestinal transport is influenced by these enzymes, we studied the effects of varying concentrations of orthovanadate (VO-4) on alanine transport in the in vitro rat jejunum. At the higher concentrations tested (10(-3) and 10(-2) M) vanadate had a ouabainlike action on alanine transport. It decreased the mucosal-to-serosal flux and the influx of alanine into the intestinal epithelium and it caused a reduction of (Na+ + K+)-ATPase activity of basolateral membranes. The relatively lower vanadate concentration of 10(-4) M increased the influx and the efflux of alanine across the mucosal border of the jejunum. The increase was associated with elevation of cyclic AMP in the intestinal mucosa. The studies suggest the presence of a dual action of vanadate on amino acid transport, a stimulatory effect at low concentration, due to increased adenylate cyclase activity, and an inhibitory effect at higher concentrations, due to a decreased activity of (Na+ + K+)-ATPase.
据报道，钒酸盐可抑制多种细胞的（钠+钾）-ATP酶，并且在某些系统中可刺激腺苷酸环化酶。由于肠道转运受这些酶的影响，我们研究了不同浓度的原钒酸盐（VO-4）对体外大鼠空肠中丙氨酸转运的影响。在所测试的较高浓度（10^(-3)和10^(-2) M）下，钒酸盐对丙氨酸转运具有哇巴因样作用。它降低了从黏膜到浆膜的通量以及丙氨酸进入肠上皮的内流，并导致基底外侧膜的（钠+钾）-ATP酶活性降低。相对较低的10^(-4) M钒酸盐浓度增加了丙氨酸穿过空肠黏膜边界的内流和外流。这种增加与肠黏膜中环磷酸腺苷的升高有关。这些研究表明钒酸盐对氨基酸转运存在双重作用，低浓度时具有刺激作用，这是由于腺苷酸环化酶活性增加，而高浓度时具有抑制作用，这是由于（钠+钾）-ATP酶活性降低。
