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Alcohol‐induced Enhancement of Intestinal γ‐Glutamyl Transpeptidase Activity in Rats and Humans: A Possible Role in Increased Serum γ‐Glutamyl Transpeptidase Activity in Alcoholics
Author(s) -
Ishii Hirornasa,
Watanabe Yoko,
Okuno Furnio,
Takagi Toshikazu,
Munakata Yoshio,
Miura Soichiro,
Shigeta Yohsuke,
Tsuchiya Masaharu
Publication year - 1988
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1988.tb00142.x
Subject(s) - gtp' , lamina propria , medicine , lymph , endocrinology , ethanol , small intestine , lymphatic system , chemistry , biology , biochemistry , pathology , immunology , epithelium , enzyme
It is a well‐known phenomenon that serum γ glutamyltranspeptidase (γ‐GTP, EC 2.3.2.2.) activity is increased after chronic consumption of ethanol, and γ‐GTP has been, therefore, widely used as a sensitive marker for detection of alcoholism and its related liver disease. However, the precise mechanisms whereby the chronic ethanol consumption leads to an increase in serum γ‐GTP activity are not fully understood. In the present study, we investigated the relationship between the intestinal and serum γ‐GTP activities after chronic ethanol consumption both in rats and humans. Chronic ethanol feeding to rats resulted in a significant increase in serum γ‐GTP activity associated with a significant increment of the intestinal γ‐GTP activity. The histochemical staining of γ‐GTP in the mucosa of the small intestine of these animals demonstrated enhanced γ‐GTP activity at the microvilli of the brush border membrane, lamina propria of the mucosa, and endoplasmic reticulum of the intestinal epithelial cell. The augmented activity in the lamina propria was mainly localized at the submucosal lymphatics. Histology of the small intestine of human alcoholics was, more or less, similar to those observed in alcoholic rats. We further investigated the γ‐GTP activity in the mesenteric lymph using the animal model of lymphorrhea, and found that the γ‐GTP activity was increased by 83% when expressed per unit of lymph in the ethanol‐fed rat, accompanied by a marked decrease of serum γ‐GTP activity, suggesting a close relationship between the serum and the intestinal γ‐GTP via the lymphatic channel. In conclusion, an increased serum γ‐GTP activity, which is frequently observed in alcoholics, may, at least in part, originate from the enhanced activity of the intestinal γ‐GTP.