No abstract

ExtractThe relations of total zinc, manganese, nucleic acids, and protein in the livers of control, hypophysectomized, and calorie-restricted rats were evaluated by regression analysis and analysis of covariance (tables I through V).The most striking findings were the demonstration of a continuous relation between RNA and zinc in the livers of the control rats and of experimental groups ( fig. 2), and an absolute increase in the content of manganese in the livers of the calorie-restricted animals ( fig. 3).It is suggested that zinc is important for the maintenance of ribonucleic acid synthesis and subsequent protein synthesis in mammalian tissues. SpeculationIn biological tissues, ribonucleic acid is a necessary precursor for protein synthesis; possibly zinc, acting as a cofactor, is of equal importance. Introductionacid (DNA), ribonucleic acid (RNA), and protein.These interrelations are considered for control rats, In an earlier paper [3] it was reported that during a rats receiving adequate protein but inadequate calories, variety of circumstances affecting growth of rats and for rats that had been hypophysectomized. (endocrine imbalance, calorie restriction) the ratios Regression equations presented in this communicain liver of both zinc and ribonucleic acid to deoxyribo-tion contain a common factor, liver weight, through nucleic acid appeared to parallel each other closely. which both the dependent and independent variables This suggested that the two components were related are calculated. This, of course, leads to somewhat within the cell. The present study was designed to spurious correlations. The emphasis of the statistical examine the relation of zinc and manganese to nucleic analysis, however, is not on the fitted equations but acids and protein within the rat liver by more definitive on the comparisons of the sets of data by analysis of statistical methods in order to strengthen or discard covariance. This permits comparisons of animals of the previous finding. varying ages and sizes in a way that is biologically Statistical analysis, namely regression analysis and meaningful. analysis of covariance, was utilized to inspect the relaAnalysis of covariance affords a sensitive statistical tion of total zinc (Zn) and also total manganese (Mn) method by which two regression lines may be compared in rat liver with the liver content of deoxyribonucleic to determine whether they are from two different pop-