Age-dependent variation of zinc-65 metabolism in LACA mice.
Mice were gavaged with zinc-65 solution, 8.6-19.3 kBq per mouse, and the whole-body retention and organ content of zinc-65 were measured at different times after administration. The age-dependence of the fractional absorption of zinc-65 from the gastrointestinal tract (f1), the endogenous faecal excretion fraction of zinc-65 (EFEF), tissue distribution and whole-body retention were determined. The f1 values obtained were 0.86 +/- 0.15, 0.64 +/- 0.11, 0.52 +/- 0.07 and 0.39 +/- 0.02 in suckling, adolescent, young adult and older mice, respectively. The EFEF values determined were 0.083 +/- 0.008, 0.099 +/- 0.004, 0.122 +/- 0.018 and 0.144 +/- 0.005 of intraperitoneally injected zinc-65 in suckling, adolescent, young adult and older mice at administration. Zinc-65 mainly distributed in the liver, muscle, lung, kidneys and bone. In some tissues, there was an inverse relationship between the relative content of gavaged zinc-65 and the animal's age at administration. The whole-body biological half-lives of zinc-65 increased with animal age. The influence of the age-dependent variation of zinc-65 metabolism on internal dose and on radiation protection is discussed.
Department of Radiotoxicology, Institute of Radiation Medicine, Beijing, China.
L S
LS
He
X S
XS
Yan
D C
DC
Wu
D000284:Administration, Oral; D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D005243:Feces / Q000737:chemistry; D007274:Injections, Intraperitoneal; D007408:Intestinal Absorption / Q000502:physiology; D007700:Kinetics; D008657:Metabolic Clearance Rate / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D009929:Organ Size / Q000187:drug effects; D011835:Radiation Protection / Q000592:standards; D014018:Tissue Distribution / Q000502:physiology; D014916:Whole-Body Irradiation; D015037:Zinc Radioisotopes / Q000032:analysis / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology
D015037:Zinc Radioisotopes