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

Abstract

ALTHOUGH there are many biological studies dealing with zinc, little quantiative data have appeared regarding the concentration and turnover of this metal, especially for man. 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).While its biological significance is established, the physiological role of zinc remains to be elucidated. Important contributions to our understanding of the part played by the element should result from investigations which employ 65Zn. Precise data are not yet available as to the fraction of the administered radioisotope which is taken up by the various organs. Quantitative concentration data are unavailable for the prostate; moreover, the particular sites and structures of the gland associated with 65Zn uptake have not been identified.Following our earlier study of the distribution of 65Zn in blood and its excretion in man (Graig and Siegel, 1960), the present investigation was undertaken to learn more about the concentration of the radioisotope by several organs with special attention to the prostate. For the latter, it was also sought to ascertain which glandular components are implicated in the accumulation of 65Zn. MATERIALS AND METHODSAutopsy studies. Fourteen pre-terminal patients having various malignancies were given approximately 100 ,uc 65Zn (specific activity greater than 75 mc/g.) as the chloride. The radioisotope was administered as an intravenous infusion in a 250 ml. volume of isotonic solution. At autopsy, which occurred between 1 and 174 days after the infusion, portions of the following organs were obtained, whenever possible, for digestion and the assay of 65Zn: liver, pancreas, spleen, prostate, seminal vesicles, lung, bladder and skeletal muscle.Studies on prostatic surgical specimens. Tracer doses of 65Zn (approximately 50 ,uc) were administered in the manner described above to 36 patients presumed to have diseased prostates and awaiting surgery. A sample of each surgical

A comparison of the short-term kinetics of zinc metabolism in women during fasting and following a breakfast meal

“…Radioactive tracer studies of Zn metabolism in human subjects and animals show that the pancreas actively takes up Zn (Siegel et al 1961), and that pancreatic Zn has a rapid turnover rate (Sheline et al 1943). Zn is required for the synthesis of pancreatic enzymes that are released into the duodenum.…”

ICRP Publication 134: Occupational Intakes of Radionuclides: Part 2

“…The amount of zinc lost in sweat under normal conditions appears to be of the same order as losses in urine (Jacob et al., 1981; Johnson et al., 1993). (390) Following acute entry of labelled zinc into blood, 60% or more of the label accumulates rapidly in the liver (Siegel et al., 1961; Spencer et al., 1965; Aamodt et al., 1979). Relatively high concentrations are also seen in the kidneys and pancreas at early times (Siegel et al., 1961; Spencer et al., 1965).…”

“…(390) Following acute entry of labelled zinc into blood, 60% or more of the label accumulates rapidly in the liver (Siegel et al., 1961; Spencer et al., 1965; Aamodt et al., 1979). Relatively high concentrations are also seen in the kidneys and pancreas at early times (Siegel et al., 1961; Spencer et al., 1965). Over a period of weeks, the label shifts largely to skeletal muscle and bone, which have low rates of accumulation but long retention of zinc (McKenney et al., 1962; Khristov, 1970; Aamodt et al., 1982).…”

Age‐related macular degeneration and nutritional supplementation: a review of randomised controlled trials

“…Zinc is highly concentrated in ocular tissues, particularly the retina and pigment epithelium (Siegel et al ., 1961; Galin et al ., 1962; Swanson and Truesdale, 1971; Eckhert, 1979; Ujiie, 1979). It acts as a cofactor for the antioxidant enzymes retinal dehydrogenase and catalase (Sigel, 1983) and is also involved in retinal metabolism.…”