Massage-like stroking influences plasma levels of gastrointestinal hormones, including insulin, and increases weight gain in male rats.

The aim of the present study was to investigate the effects of repeated massage-like stroking on plasma levels of some gastrointestinal hormones, insulin included, glucose and weight gain. For this purpose, male rats were exposed to stroking on the ventral side of the abdomen for 3 or 14 times. The treatments were given every second day. Control rats were picked up at the same time but received no stroking. Body weight was measured regularly. Rats were decapitated 10 min after the last treatment. Hormone levels were radioimmunoassayed and glucose was measured by spectrophotometry. In rats exposed to 3 sessions of massage-like stroking plasma levels of insulin (p<0.05) and somatostatin (p<0.01) were significantly decreased 10 min after the last treatment. After 14 treatments of massage-like stroking, decreased plasma levels of insulin (p<0.01) and gastrin (p<0.01) as well as increased glucose levels (p<0.01) were observed 10 min after the last treatment. In addition, weight gain was significantly increased (ANOVA p<0.0001) in rats exposed to 14 treatments. In conclusion, repeated massage-like stroking decreased plasma levels of gastrin, insulin and somatostatin, increased plasma levels of glucose and promoted weight gain. The effects were influenced by the number of treatments.