The inhibitory effect and the mechanism of ethanol absorption by zinc complex in mouse gastrointestinal tract

Abstract

The inhibitory effect of ethanol absorption by zinc cysteine (Cys-Zn) and zinc acetylcysteine (ACys-Zn) were studied in mice. The mice orally received Cys-Zn, ACys-Zn, Cys or Zn acetate, and after 1 hr, ¹⁴C-ethanol was given orally or intraperitoneally (i.p.). At various times, blood was drawn from the tail vein and ¹⁴C-radioactivities determined. Cys-Zn and ACys-Zn inhibited the appearance of ¹⁴C-radioactivities in blood following oral ¹⁴C-ethanol loading, but Cys and Zn acetate caused no changes as compared to the control. Cys-Zn pretreatment did not induce any change in the blood ¹⁴C-radioactivity when ethanol was given i.p. The levels of ¹⁴C-radioactivity and zinc in the gastrointestinal tract after oral administration (adm) of Cys-Zn and ¹⁴C-ethanol were significantly higher than those of the control for 7 hr. At 72 hr after adm, the urinary and fectal excretions of ¹⁴C-radioactivity were low when Cys-Zn was given at the dose of 5.0% or 0.5%. The excretion of ¹⁴C-radioactivity through expiration in both cys-Zn and control mice was about 28% of the dose at 5 hr after adm. Distributions of ¹⁴C-radioactivities in other organs of Cys-Zn treated mice were lower then those of the control. In the vitro study, Cys-Zn stimulated the metabolism of ethanol to acetaldehyde and acetic acid in the 9, 000 g supernatant of the small intestine. The results suggest that zinc complex shows a long-term adhesive and permeable action on the gastrointestinal tract in mice, and this inhibited ethanol absorption.