Effect of aging on plasma cholecystokinin secretion and gallbladder emptying

Abstract

The present study was undertaken to examine the effect of aging on cholecystokinin (CCK) release, gallbladder emptying and their interrelationships. Therefore, 26 healthy subjects were studied, 13 younger than 40 yr (mean age 31 yr, range 21–39 yr) and 13 older than 40 yr (mean age 64 yr, range 40–78 yr). After intraduodenal administration of 60 ml corn oil, plasma CCK concentration was measured by a sensitive and specific radioimmunoassay and gallbladder emptying by cholescintigraphy. Fasting plasma CCK concentrations were similar in both groups (1.2±0.2 pmol/l in the younger and 1.5 ± 0.3 pmol/l in the older subjects), but the integrated postprandial CCK secretion was significantly (p<0.01) increased in the older subjects (214±21 pmol/l. 60 min) compared to the younger subjects (153±15 pmol/l. 60 min). However, gallbladder emptying was not significantly different between the older and younger subjects (at 60 min 55±7% vs. 61±4%). Gallbladder sensitivity to endogenous CCK was significantly (P<0.02) reduced in the older subjects when compared to the younger subjects. In conclusion, gallbladder sensitivity to CCK is diminished in older subjects but gallbladder emptying remains unchanged due to a significantly increased endogenous CCK secretion.