The effect of secretin on serum group I pepsinogens (PG I) in man.

Six healthy young males were studied with an intravenous infusion of secretin, 2 CU/kg body weight and hour in saline, or with saline alone for 3 h on two separate days. Blood was drawn before and at regular intervals during the infusions, and serum PG I was determined by radioimmunoassay. After an initial decline on both days, serum PG I rose significantly during the secretin infusion. The initial fall in serum PG I was probably not caused by heparin used to keep the indwelling catheter open, since a similar fall was also observed in another six subjects in whom saline was used to keep the catheter open. Moreover, heparin added to the serum did not affect the measurement of PG I.