Vitamin A deficiency alters the bioelectric parameters and RNA content of rat gastric mucosa in vitro.
The present study was aimed to investigate the mechanisms by which vitamin A plays a role in maintaining the efficiency of gastric mucosal barrier. Particularly, we measured electrical parameters and the RNA/DNA ratio of gastric mucosa isolated in vitro from the stomach of rats in which vitamin A-deficiency was induced by means of a vitamin A-free diet and then abolished by means of a massive vitamin A supplementation. Pair-fed vitamin A-nondepleted rats and normal rats fed ad libitum on a standard diet served as controls. Vitamin A status was assayed for each group of rats by measuring the hepatic content of vitamin A. We found that in gastric mucosa vitamin A-deficiency induced: 1) a decrease in both transmucosal potential difference and short-circuit current; 2) an increase in transmucosal electrical resistance; 3) a decrease in RNA content resulting in a decreased RNA/DNA ratio. Abolishment of vitamin A-deficiency restored both electrical parameters and RNA content of rat gastric mucosa. Our results stress the role of vitamin A in maintaining the efficiency of the gastric mucosal barrier. Vitamin A seems to act by stabilizing gastric electrical parameters and by controlling the protein synthesis/turnover in the surface gastric mucosal cells.
Ventura
U
U
Department of Experimental Medicine, Section of Human Physiology, University of Pavia, Pavia, Italy. ventura@unipv.it
Ceriani
T
T
Montini
E
E
Romano
M
M
Ricci
V
V
D000284:Administration, Oral; D000818:Animals; D004247:DNA / Q000737:chemistry; D004032:Diet / Q000009:adverse effects; D004334:Drug Administration Schedule; D004594:Electrophysiology; D004847:Epithelial Cells / Q000378:metabolism; D005753:Gastric Mucosa / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D008297:Male; D014176:Protein Biosynthesis; D011506:Proteins / Q000737:chemistry / Q000187:drug effects; D012313:RNA / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014801:Vitamin A / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use; D014802:Vitamin A Deficiency / Q000378:metabolism* / Q000503:physiopathology* / Q000517:prevention & control
D011506:Proteins; D014801:Vitamin A; D012313:RNA; D004247:DNA