Differences in leptin biosynthesis in the stomach and in serum leptin level between men and women.

Background and Aim Although the stomach has been identified as an important source of leptin, the detailed biosynthesis sites of leptin in human gastrointestinal tract have not been fully elucidated. The study objective was to compare leptin distribution and expression in the stomach and its serum level between healthy men and women. Methods Nineteen subjects (organ donors; 10 men and 9 women) with normal gastric mucosa histology were recruited. Research material contained gastric samples from the cardia, fundus, and pyloric regions. Gastric mucosa leptin content and leptin gene expression were determined by immunohistochemistry and real-time polymerase chain reaction method. Plasma leptin level was measured using ELISA method. Results In the stomach of healthy adult subjects, leptin-immunoreactive cells were mainly found in the fundus, and the number of immunoreactive cells was higher in women than in men. Leptin-containing cells were less numerous in the cardia and pylorus mucosa. Similarly, leptin gene expression was the highest in the fundus and higher in women than in men. Serum leptin level was higher in women than in men and was found to correlate positively with body mass index and weight in both sexes. A negative correlation between leptin level and age was noted in women, but not in men. Conclusions The current study is the first to provide evidence for the presence of leptin-containing cells in all segments of the human stomach. The differences in gastric leptin biosynthesis and serum leptin levels between men and women suggest that leptin secretion can be controlled by sex hormones or other unknown factors.