Influence of body weight and growth rate on nitrogen and electrolyte excretion in rats.

Abstract

ConclusionYoung male rats that differed in body weight by only about 20% had significant(p ≦ .05) metabolic differences during a 3-day fast. These included calcium, phosphate, urea, creatinine, the Na/K, Mg Ca, Ca/PO4 and uric acid/creatinine ratios. There was an almost 10-fold difference in their respective growth rates, however, which undoubtedly contributed to the differences. These group differences tended to disappear in almost all variables as the fast progressed. The various ratios proved to be quite sensitive to the group differences.