[Effect of calcitonin on gallbladder volume between food intake and on its emptying after meals in humans].

The effect of increasing i.v. doses of synthetic salmon calcitonin: 0.0044, 0.0088, 0.0175, and 0.0350 i.u..kg-1 min-1 versus placebo on the fasted gallbladder volume was assessed in 7 normal subjects according to a double-blind study protocol. In addition the action of calcitonin on meal-induced gallbladder emptying was examined. Gallbladder volumes were measured by means of real-time ultrasonography. An excellent day-to-day reproducibility of the fasted gallbladder volume was reflected by a coefficient of variation amounting to 12.2%, whereas the correlation coefficient between the fasted gallbladder volumes on day 1 and 2 amounted to r = 0.98, p less than 0.001. Calcitonin evoked a dose-dependent relaxation of the fasted gallbladder. A statistically significant increase of the fasted gallbladder volume was observed with 0.0175 (23.4 +/- 5.50 cm3 placebo vs 33.9 +/- 7.74 cm3 calcitonin, p less than 0.001) and 0.0350 (21.4 +/- 4.62 cm3 placebo vs 36.1 +/- 8.42 cm3 calcitonin, p less than 0.01) i.u..kg-1 min-1 calcitonin, where as mean increase of the gallbladder volume amounted to 32.1 and 46.5%, respectively. A significant delay of the gallbladder emptying after calcitonin was reflected by a decrease of the ejection fraction: 23.2 +/- 8.33% calcitonin vs 57.8 +/- 6.94% placebo (p less than 0.02) at 20 min, and 40.5 +/- 8.76% calcitonin vs 67.2 +/- 3.75% placebo (p less than 0.02) at 30 min after the test meal. Calcitonin is concluded to increase significantly the interdigestive gallbladder volume and to delay the meal-induced gallbladder emptying in humans.