INTERACTION OF TYPE-I AND TYPE-II CORTICOSTEROID RECEPTOR STIMULATIONON CARCASS ENERGY AND CARCASS WATER

The effects of chronic type I and type II corticosteroid receptor stim ulation were examined in adrenalectomized Sprague-Dawley rats to quant ify the relative contribution of body energy and body water changes to changes in body weight. Adrenalectomy caused a decrease in both body energy and water. Aldosterone (type I agonist) treatment increased bod y weight gain and returned energy accretion to the level of sham-opera ted animals. However, most of the change in body weight (72%) was attr ibutable to a change in body water. The aldosterone-induced increases in body weight gain and carcass water were attenuated by RU-28362 (typ e II receptor agonist) infusion, suggesting that type II receptor stim ulation can antagonize the effect of type I receptor stimulation. Chan ges in carcass water were paralleled by changes in soluble carcass sod ium. Despite alterations in soluble body sodium, no measurable differe nces in cumulative sodium retention were found. These findings confirm previous studies suggesting an effect of type I receptor stimulation on energy accretion. However, they also caution that changes in body w eight cannot be equated with changes in body energy.