Role of gastric glutathione in smoke flavouring-induced gastric injury in rats.
Some commercial liquid smoke flavourings have been shown to induce acute gastric mucosal injury in rats when given orally as a large single dose. The present study was carried out to examine the mechanism of action in rats of two selected smoke flavourings containing about 10% total acids as acetic acid. These flavourings and 10% acetic acid decreased the concentration of glutathione (GSH) in the glandular stomach. The decrease in gastric GSH was coupled with smoke flavouring-induced gastric injury. Pretreatment with N-ethylmaleimide, a GSH depletor, enhanced acetic acid-induced gastric injury. Pretreatment with cysteine, a sulphhydryl compound, protected rats against smoke flavouring-induced gastric injury. Aqueous fractions of the smoke flavourings, after removal of non-polar compounds and acidic organic compounds (including acetic acid) by diethyl ether extraction, decreased the gastric GSH concentration considerably and had a marked reactivity in vitro with GSH, but these fractions by themselves showed no ability to induce gastric injury. Addition of 10% acetic acid to these aqueous fractions caused greater gastric injury than 10% acetic acid alone, which suggests that these aqueous fractions contain the (unidentified) compound(s) that facilitate acetic acid-induced gastric injury. These findings indicate that gastric endogenous and exogenous sulphhydryls play an important part in gastric cytoprotection.
Shimizu
M
M
Osaka City Institute of Public Health and Environmental Sciences, Japan.
Nakama
A
A
Yamano
T
T
Noda
T
T
Fujita
T
T
Kuroda
K
K
Yamada
A
A
Morita
S
S
D000085:Acetates / Q000633:toxicity*; D019342:Acetic Acid; D000284:Administration, Oral; D000818:Animals; D003545:Cysteine / Q000494:pharmacology; D005421:Flavoring Agents / Q000633:toxicity*; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005978:Glutathione / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012906:Smoke; D014934:Wood
D000085:Acetates; D005421:Flavoring Agents; D012906:Smoke; D005978:Glutathione; D003545:Cysteine; D019342:Acetic Acid