Effects of oxytocin on the IGF-axis and some gastrointestinal hormones in ad libitum fed and food-restricted female rats

The aims of this study were to investigate if administration of oxytocin to ad libitum fed and food-restricted female rats affects weight gain, body f atness. the IGF-axis, and some vagally mediated gastrointestinal hormones, such as gastrin, chotecystokinin (CCK) and somatostatin. Ad libitum fed and food-restricted (receiving 70% of the food intake of the ad libitum fed gr oup) female rats were injected subcutaneously. once a day. for 10 days, wit h saline (control) or oxytocin (1 mg kg(-1) bodyweight). The animals were k illed 5 days after the last injection. Oxytocin-treated food-restricted fem ales had more body fat and lower plasma levels of IGF-I, IGFBP-1 and IGFBP- 3 compared with saline-treated counterparts. Oxytocin-treated ad libitum fe d rats also had lower plasma levels of IGFBP-1 but contained less body fat. compared with saline-treated counterparts. There was no effect of oxytocin treatment on body weight or weight gain in either or the feeding groups. E xcept for gastrin, which was lower, there was no effect of oxytocin on the gastrointestinal hormones studied. The results indicate that oxytocin treat ment influences fat deposition and the IGF-axis in female rats, but that th e results are dependent on the nutritional status of the animal.