Some Observations on the Distribution of Radioactive Zinc in Prostatic and Other Human Tissues

Abstract

SUMMARY Intravenous injections of 65Zn containing 50 to 100 μc. of radioactivity and 50 to 100 μg. of carrier zinc have been given to fifteen patients suffering from various forms of malignant disease and the radioactive content of blood and other tissues estimated twenty to ninety‐six hours later. Results expressed as 65Zn organ/blood ratios have been compared with zinc organ/blood ratios calculated from data reported by other workers from chemical determinations on similar tissues. The radioactive and chemical ratios are generally of the same order with the exception of muscle which had a much lower, and liver and certain samples of carcinomatous prostatic tissue which had a much higher 65Zn ratio than Zn ratio. Carcinomatous prostatic tissue from one patient had a 65Zn tissue/blood ratio of 40, which is twice as much as the highest ratio found in any other tissue. This study was supported by the New York Cancer Committee and the Lerner Fund. The writers gratefully acknowledge the assistance of Miss Eva Simmel in preparing the autoradiographs.

Distribution of 65Zn in the Prostate and other Organs of Man

“…This comparatively poor localization dims the hope of applying such in vivo counting techniques for diagnosis or for determining indices of function, unless much higher ratios are encounltered for pathological states of the prostate. Our findings are in accord with the meager evidence available (Mawson and Fischer, 1952 ;Daniel et al, 1956;Prout et al, 1959;Kerr et al, 1960) which suggests that the reverse is more probable.…”

“…The localization of 65Zn by the border epithelium is in accord with the radioautograph published by Daniel et al (1956) for human prostate and with those presented by Wetterdal (1958) and Millar, Vincenlt and Mawson (1961) for the dorsolateral prostate of the rat. Using the dithizone stain, Mager et al (1953) studied the prostates of the dog, man, monkey and rabbit, reporting that the apical portions of the secretory cells were most intensely stained.…”

“…While an eight-fold variation was found in the necropsy specimens from eight male patients, an even greater ratio of about 15 was encountered in the surgical specimens from 36 patients 660 E. SIEGEL, F. A. GRAIG, M. M. CRYSTAL AND ELSIE P. SIEGEIL (Table III). A factor of only 12 is indicated in the series of 15 patients studied with 65Zn by Daniel et al (1956) and an even smaller ratio, about seven, is found for the 21 cases investigated by Prout et al (1959). It should be noted that stable zinc levels are likewise variable, Hoare, Delory and Penner (1956) having observed an 11-fold range in 19 normal prostates.…”

“…The liver, however, is a notable exception, since it takes up a much higher fraction of the 65Zn dose than its relative content of the stable metal. MIeselhan et al (Daniel et al, 1956;Prout et al, 1959;Ross et al, 1958) and the dog (Sheline et al, 1943;Meschan et al, 1959), but are higher than the corresponding values for the mouse (Sheline et al, 1943) and rat (Gilbert and Tavlor, 1956;Ballou, 1959). The variation of 65Zn uptake in the liver with time is noteworthy (Fig.…”

“…Interest in zinc metabolism has been stimulated-by the accumulating evidence which indicates that this metal is a constituent of several enzymes (Fischer, Tikkala and Mawson, 1955;Vallee, 1955) and is associated, also, with some pathological states (Daniel et al, 1956;Prout, Sierp and Whitmore, 1959; Herring et al, 1961;Fredricks, Tanaka and Valentine, 1960). Our concern with the element stems from reports of the high concentration of zinc found in the prostate gland both in animals (Gunn et al, 1955) and man (Mawson and Fischer, 1 952).…”