COMPARATIVE-STUDY OF DIFFERENT METHODS OF INDUCING ACUTE AND CHRONIC HYPERCALCEMIA IN RATS

Experimental studies are frequently carried out using calcium salt tre atment in rats. Modifications in plasma calcium levels could suggest i mportant changes in cellular functions, transmitters and drug response s. Changes during continuous maintenance of hypercalcemia could, on th e other hand, be different from those produced by an acute increase in calcemia Nevertheless, to date no specific studies exist which evalua te and compare the modifications in calcemia and other alterations whe n different methods of administering acute and chronic calcium are use d in rats. This paper presents a method for inducing acute hypercalcem ia in Sprague-Dawley rats after intraperitoneal administration of diff erent quantities of CaCl2. Different oral calcium treatments to induce chronic hypercalcemia were also evaluated. Hypercalcemia was more con sistent when calcium was administered in both the solid and liquid die ts. On day 14 of treatment the highest total and ionic plasma calcium levels appeared in rats fed with CaCO3 in the solid diet (4% Ca) and w ith CaCl2 in the liquid diet (1.5% Ca). With this treatment hypercalce mia was maintained for 2 months.