INFLUENCE OF ENDOGENOUS SOMATOSTATIN ON LACTATION IN RATS

The role of endogenous somatostatin on lactation in rats was examined by passive immuno-neutralization of Wistar rats. In one study, the rats were given either immunoglobulin raised in sheep against somatostatin, or non-specific sheep immunoglobulins by daily s.c. injection from parturition through the first two weeks of lactation. The growth of the pups was recorded by weighting every second day, and the milk yield calculated from the pup weight and weight gain. Immunoneutralization of maternal somatostatin during pregnancy had a slight effect (p < 0.05) on the mean birth weight of the pups but no subsequent effect on postnatal growth rate of the pups or milk yield ($25.32{\pm}0.88g/day$) compared with young control rats given normal sheep serum ($25.55{\pm}1.04g/day$). Similarly, passive immunization against somatostatin during lactation ($21.96{\pm}1.57g/day$) also did not affect milk yields compared with controls ($24.85{\pm}1.03g/day$). These data do not support a significant role for endogenous somatostatin in regulating milk production in lactating rats.