Changes in the blood gas concentration caused by secretin and cholecystokinin. Indication of a vasomotor effect?

The assumption that secretin has a general vascular effect led to an investigation of the blood gas level in the peripheral veins and the acid/base balance under the influence of secretin (1 CU/kg/h, 0-120 min) and cholecystokinin (CCK) (1 IU/kg/h, 60-120 min) in a group of 10 volunteers. Six of the volunteers were subjected to a randomized, cross-over NaCl infusion study. With a secretin infusion alone (0-60 min) there was a transient, significant rise in PO2 (p less than 0.01) and oxygen saturation (p less than 0.05), which was no longer detectable after 60 min (p greater than 0.05). With an additional administration of CCK (60-120 min) and in the follow-up phase of observation (120-180 min) there was a significant fall in both parameters (120 min: p less than 0.05, 180 min: p less than 0.01). PCO2, HCO-3, and pH remained unaffected. The isolated increase in PO2 and O2 saturation may be attributed to vasodilation induced by secretin. The drop in both parameters under the influence of an additional infusion of CCK and in the follow-up phase of observation is linked to a possible vascular effect of CCK.