[Secretin and cholecystokinin: hormonal action on the concentration of vasoactive intestinal polypeptide and gastrin in human subjects?].

There is little, and partially contradictory information about the mutual hormonal effects of peptides. With the help of volunteers we investigated the influence of a new synthetic secretin (1 CU/kg/h, 0 to 120 min.) alone and in combination with GIH-CCK (1 IU/kg/h, 60 to 120 min.) on the concentration of VIP (n = 13) and gastrin (n = 20). Six of the volunteers were subjected to a randomized cross-over study under NaCl infusion in which both peptides were determined. The VIP concentration was not significantly influenced (31 +/- 3 - 34 +/- 4 - 38 +/- 4.5 pg/ml, p greater than 0.05) by either secretin (0 to 60 min.) or by secretin and CCK (60 to 120 min.). In contrast, secretin induced a significant fall in the gastrin level (30 +/- 2 vs. 24 +/- 2 pg/ml, p less than 0.05). With an additional administration of CCK there was a significant rise in gastrin (75 min.: 46 +/- 3 pg/ml, p less than 0.005) with a decline in peptide levels at the end of the infusion (135 min.: 23 +/- 2 pg/ml, p less than 0.005). The cross reactivity with GIH-CCK and CCK-octapeptide was 2.4 and 3% respectively. The increase in gastrin is not regarded as being due to cross reaction with CCK. This may be due to either contamination of the CCK preparation by other peptides which exert an influence on the gastrin level or the CCK induced release of bile.