Elevated serum and antral gastrin in obese (ob/ob) mice.

Elevations in serum gastrin concentration of six to seven times were found in postabsorptive 5- and 10-wk-old, but not 30- and 40-wk-old, obese mice in comparison with the appropriate lean controls. At 10 wk of age a fourfold hypergastrinemia was also evident in (ob/ob) mice denied food for 48 h. In 10-wk-old (ob/ob) mice that had eaten the same amount of food as lean mice from weaning, serum gastrin was six times that of lean controls. Antral gastrin concentration was 54% higher in fed 10-wk-old (ob/ob) mice than in lean mice. No relationship was found between alterations in serum gastrin and measures of gastrointestinal size or proliferative status. Maximal gastric acid output, expressed with respect to oxyntic mucosal dry weight, was reduced by 52% in 10-wk-old (ob/ob) mice compared with lean controls. It is concluded that the hypergastrinemia of 10-wk-old (ob/ob) mice is not caused by hyperphagia, but may be a consequence of reduced acid inhibition of gastrin release.