ADRENOCORTICAL STIMULATION BY A CHOLECYSTOKININ PREPARATION IN THE RAT

The effect of a cholecystokinin (CCK) preparation on the secretion of corticosterone when injected intraperitoneally and intraventricularly was studied in the rat. Both routes of injections produced pronounced elevation of plasma corticosterone levels, but the minimum effective dose by intraventricular injection was 10 mU/rat and that by intraperitoneal injection 2 U/100 g, or approximately 5 U/rat. Although the effect was observed in vagotomized rats, CCK did not affect the pituitary gland itself. It was inferred that CCK acts directly or indirectly on CRF neurones in the brain. Since CCK preparation used in the present experiments was contaminated with motilin, the effect of synthetic motilin on the adrenocortical secretion was also examined. However, no stimulatory effect was found following intraventricular injection of this peptide. © 1979.