Effects of bovine alpha-lactalbumin on gastric defense mechanisms in naive rats

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2003-01, Vol.67 (3), p.577-583
• Main Authors: Ushida, Y. (Morinaga Milk Industry Co. Ltd., Zama, Kanagawa (Japan)), Shimokawa, Y, Matsumoto, H, Toida, T, Hayasawa, H
• Format: Article
• Language: English
• Subjects: Administration, Oral; ALBUMINS; Animals; Biological and medical sciences; Cattle; COW MILK; defense mechanism; Dinoprostone - analysis; Dinoprostone - biosynthesis; Dose-Response Relationship, Drug; Fundamental and applied biological sciences. Psychology; Gastric Emptying - drug effects; Gastric Juice - drug effects; Gastric Juice - metabolism; Gastric Mucins - analysis; Gastric Mucins - biosynthesis; Gastric Mucosa - drug effects; Gastric Mucosa - metabolism; gastroprotection; Hydrogen-Ion Concentration; Lactalbumin - metabolism; Lactalbumin - pharmacology; Male; prostaglandin; PROSTAGLANDINS; RATS; Rats, Wistar; STOMACH ULCER; Stomach Ulcer - chemically induced; Stomach Ulcer - etiology; Stomach Ulcer - metabolism; Stomach Ulcer - prevention & control; ulcer; α-lactalbumin
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.67.577

We recently investigated the effects of the major proteins in cow's milk on gastric mucosal injuries in rat ulcer models. We found that α-lactalbumin (α-LA) has marked preventive effects against gastric mucosal injuries and that prostaglandin (PG) synthesis may contribute to these effects [Matsumoto et al., Biosci. Biotechnol. Biochem., 65, 1104-1111, 2001]. In this study, we investigated the effects of α-LA on several defense mechanisms of gastric mucosa by evaluating gastric PGE 2 content, gastric mucin content, gastric luminal pH, gastric fluid volume, and gastric emptying in naive rats. Oral administration of α-LA (200, 500, and 1000 mg/kg) elevated endogenous PGE 2 levels in gastric tissue and increased the gastric mucin contents of both the gastric fluid and the adherent mucus gel layer. In addition to these PG-related responses, α-LA also caused PG-independent responses such as elevation of gastric luminal pH, increase in gastric fluid volume, and delay in gastric emptying. These responses were observed to be dose-dependent (200-1000 mg/kg of α-LA). Thus, we demonstrated that α-LA enhances both PG-dependent and PG-independent gastric defense mechanisms in naive rats. Both of these mechanisms are probably involved in its gastroprotective action.