Effect of Vanadate on Amino Acid Transport in Rat Jejunum

Abstract

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;) on alanine transport in the in vitro rat jejunum. At the higher concentrations tested and 10-2M) 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 1 OP4M 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. o 1987 Society for Experimental Biology and Medicine.Pentavalent vanadium (vanadate) is recognized as a potent inhibitor of Na-K-ATPase. 403

Nutritional Factors that Can Favorably Influence the Glucose/Insulin System: Vanadium

“…The insulin-like effects of vanadium also extend to the lipid metabolic pathways and on protein metabolism and mitogenesis [12][13][14][15][16].…”

Ванадий: Биологическая Роль, Токсикология И Фармакологическое Применение

“…В число процессов, которые ванадий стимулирует на клеточном уровне, входят метаболизм углеводов [70], ванадат-зависимое окисление NADH [65], стимуляция активности липопротеинлипазы [186], стимуляция аденилатциклазы и транспорта аминокислот [106].…”