Nicotinamide adenine dinucleotide-dependent retinoic acid formation from retinol in the human gastric mucosa: inhibition by ethanol, acetaldehyde, and H2 blockers.
All-trans retinoic acid formation from all-trans retinol (vitamin A) in the human gastric mucosa was studied. When all-trans retinol and the human gastric mucosa were incubated together, all-trans retinoic acid was formed in the presence of nicotinamide adenine dinucleotide (NAD). When the NAD was not added, hardly any formation was observed. The formation of all-trans retinoic acid tended to be attenuated by 10 mM ethanol. Moreover, it was significantly attenuated in a concentration-dependent manner by ethanol at concentrations of 100 mM and above. Acetaldehyde at concentrations of 50 microM and above also significantly attenuated its formation in a concentration-dependent manner. Some H2 blockers, which include ranitidine hydrochloride and cimetidine, significantly attenuated the formation of all-trans retinoic acid, whereas famotidine failed to suppress it. There is an NAD-dependent pathway by which all-trans retinoic acid is produced from all-trans retinol in the human gastric mucosa. Inhibitors of alcohol dehydrogenase, which include ethanol and some H2 blockers, and of aldehyde dehydrogenase, which include acetaldehyde, inhibit its production.
Yokoyama
H
H
Department of Internal Medicine, School of Medicine, Keio University, Japan.
Matsumoto
M
M
Shiraishi
H
H
Miyagi
M
M
Kato And
S
S
Ishii
H
H
D000079:Acetaldehyde / Q000494:pharmacology*; D000328:Adult; D002927:Cimetidine / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D008875:Middle Aged; D009243:NAD / Q000494:pharmacology; D011899:Ranitidine / Q000494:pharmacology; D014212:Tretinoin / Q000378:metabolism*; D014801:Vitamin A / Q000378:metabolism*
D006635:Histamine H2 Antagonists; D009243:NAD; D014801:Vitamin A; D000431:Ethanol; D014212:Tretinoin; D002927:Cimetidine; D011899:Ranitidine; D000079:Acetaldehyde