Intravenous administration of cholecystokinin (CCK) stimulates prolactin and growth hormone release in the pig.

Blood samples were taken from prepubertal pigs (n = 7) surgically prepared with venous catheters before, and at intervals during the 30 min period after, administration of physiological saline (vehicle) or sulphated cholecystokinin octapeptide (CCK) (0.3, 0.7 and 1.3 μg/kg). Plasma concentrations of prolactin and growth hormone were measured by radioimmunoassay. Statistically significant dose-related increases in prolactin occurred mainly in the first 10-min period following CCK administration. The peptide also stimulated growth hormone secretion although in a less consistent manner, with the increases tending to occur over a longer time period. Together with earlier reports showing that CCK induces cortisol release in pigs, these results suggest that the peptide's effect on anterior pituitary function could be indicative of a stress response.