Figure 1

Phosphate kinetics in rats after phosphate administration through the duodenum. (a) Experimental design of (b) and (c). The effects of duodenal administration of phosphate on normal rats (Duo group) were analyzed. A Na₂HPO₄/NaH₂PO₄ solution (phosphate 80 mM, sodium 154 mM, pH 7.4, 1.0 ml/animal) containing trace amounts of radiolabeled phosphate (³²P, 3700 Bq/ml) was administered through the duodenum at time 0. Blood samples were collected from the inferior vena cava and portal vein at the indicated time points. Organ samples were collected at 5 min. (b) ³²P levels (counts per minute (cpm)) in the blood of the inferior vena cava and portal vein (n = 4 rats per group). (c) ³²P levels in the liver, kidney, soleus, and calvaria at 5 min (n = 6 rats per group). (d) Experimental design of (e) to (i). The radiolabeled sodium phosphate solution was administered in the same manner as in (a). Levels of ³²P in the (e) liver, (f) calvaria, (g) blood from the inferior vena cava, (h) kidney, and (i) soleus were measured at the indicated time points (n = 5 rats per group). All results are presented as the means ± SDs, n.s.: not significant, Ref.: reference. *P < 0.05 based on the repeated measures of ANOVA in (b) and on Dunnett’s test in (c) and (e) to (i).