C. Marteau et A. Gerolami, INFLUENCE OF HYPERCALCEMIA ON IONIZED CALCIUM-CONCENTRATION IN PANCREATIC-JUICE OF THE DOG, The Journal of laboratory and clinical medicine, 123(4), 1994, pp. 565-573
Citations number
30
Categorie Soggetti
Medical Laboratory Technology","Medicine, General & Internal
Calcium concentration of pancreatic juice depends on secretion of calc
ium bound to enzymatic proteins or calcium diffusion from interstitial
fluids. To evaluate the relative magnitude of these pathways, we stud
ied the influence of hypercalcemia on ionized calcium (Ca++) in dog pa
ncreatic juice. Pancreatic juice was collected during basal secretion
and during stimulation by secretin or secretin plus caerulein in contr
ol conditions and under CaCl2 infusion. [Ca++] was measured by selecti
ve electrodes. Saturation of juice in CaCO3 was calculated. In stimula
ted juice, total calcium concentration ([Ca-T]) and [Ca++] were unchan
ged by hypercalcemia. In basal juice, composition was profoundly modif
ied by hypercalcemia because [Ca-T] (3.31 +/- 0.89 mmol/L vs 1.80 +/-
0.44 for controls), [Ca++] (1.44 +/- 0.37 mmol/L vs 0.84 +/- 0.24 mmol
/L for controls), and the index of saturation in CaCO3 (5.2 +/- 2.4 vs
2.9 +/- 1.8 for controls) increased significantly. Protein concentrat
ion was unchanged. This suggests that in basal conditions, the relatio
nship between plasma and juice calcium levels is due to passive inters
titial Ca++ diffusion through the pancreatic ducts. In accordance with
the hypothesis of a restricted calcium diffusion, the effects of hype
rcalcemia were flow rate dependent, being less pronounced when basal f
low rate increased. It is concluded that, in the dog, the calcium spec
ies found in stimulated juice result from a redistribution of calcium
secreted along with proteins, whereas at low secretion rate, juice cal
cium level depends mainly on interstitial Ca++ diffusion into the main
pancreatic ducts.