Postnatal oxytocin treatment of spontaneously hypertensive male rats decreases blood pressure and body weight in adulthood

Postnatal oxytocin treatment decreases blood pressure and increases body weight in adult normotensive rats. The aim of the present study was to investigate the effect of postnatally administered oxytocin on blood pressure, heart rate and body weight in spontaneously hypertensive rats (SHR). For this purpose SHR male pups were given oxytocin (1 mg/kg) or saline subcutaneously once a day on days 10–14 after birth. Blood pressure and heart rate were measured at the age of 2 months. Weight was registered continuously. The postnatally oxytocin-treated male SHR had significantly lower systolic blood pressure as adults compared to the controls (158 vs. 169; p < 0.05). They also had a tendency to lower diastolic blood pressure (119 vs. 128; p = 0.10). Heart rate was equal in the two groups. The postnatally oxytocin-treated male SHR had a significantly lower body weight at the age of 5–8 weeks compared to the controls (ANOVA p = 0.014).