Metabolic studies with Zn65. VII. Biological half-life of zinc in the guinea pig

Abstract

In order to determine the turnover of zinc in the guinea pig, we have studied in this work a way of finding the biological half-life of Zn-65 in the total of the animal and in the most significant organs of the same, which were, for the moment: pancreas, liver, genitals, kidneys, spleen, lung, heart, stomach, in­ testinos, eyes, brain and teeth. To this end we have inoculated series of from 5 to 10 guinea pigs, intraperitoneally, with an isotonic, free from pirogenous, and sterile solution of Cl3 Zn-65, at a rato of 60 microcurie/kg of weight in one sole dose. The animals being killed at the foreseen time. The above-mentioned parts were separated and, according to their characteristics, they were first incinerated or directly digcsted, an aliquot part of the resultant solution being registered on a scintillation counter. We determined the standard deviation of the average values given in Tables I and II. With the values obtained, curves were traced in a semi-logarithmics scale. In all the periods studied, of which the graphic representation is a straight line, we have found, by the method of the squares themselves, the exponential function as a starting point, we have been able to make an exact calculation of the biological half-life of the most significant organs, and for the differentiated periods.