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

Abstract

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 fatness, the IGF-axis, and some vagally mediated gastrointestinal hormones, such as gastrin, cholecystokinin (CCK) and somatostatin. Ad libitum fed and food-restricted (receiving 70% of the food intake of the ad libitum fed group) female rats were injected subcutaneously, once a day, for 10 days, with saline (control) or oxytocin (1 mg kg-1 bodyweight). The animals were killed 5 days after the last injection. Oxytocin-treated food-restricted females 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 fed 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 of the feeding groups. Except for gastrin, which was lower, there was no effect of oxytocin on the gastrointestinal hormones studied. The results indicate that oxytocin treatment influences fat deposition and the IGF-axis in female rats, but that the results are dependent on the nutritional status of the animal.