Cadmium‐109 metabolism in mice. I. Organ retention in mice fed a nutritionally sufficient diet during successive rounds of gestation and lactation

Abstract

Organ retention of ¹⁰⁹Cd was studied in multiparous and virgin female mice provided tracer amounts of ¹⁰⁹Cd in drinking water and stable Cd appropriate for the itai‐itai experience in an otherwise nutrient replete solid diet. Breeder females maximally experienced 6 consecutive, 42‐d rounds of gestation/lactation. On a round‐by‐round basis, breeder organ ¹⁰⁹Cd content and concentration values were compared with those from their time‐matched virgin controls. By the end of round 5, the ¹⁰⁹Cd contents of some organs appeared to have plateaued in consecutive breeders. Comparing breeder with control values at that point, the following increases were observed: whole body (minus gastrointestinal tract), 4.7‐fold; mammary tissue, 14.1‐fold; liver, 5.9‐fold; and kidney, 3.8‐fold. For ¹⁰⁹Cd concentrations, analogous increases were mammary tissue, 15.3‐fold; liver, 4.0‐fold; and kidney, 2.4‐fold. Through the six rounds, a temporal shift in fractional ¹⁰⁹Cd distribution was noted for breeder tissues where transfer occurred from those of the mammaries, remaining carcass, and liver to the kidneys. In spite of this shift, at the end of round 6 ¹⁰⁹Cd content in hepatic tissue still exceeded that in renal tissue; however, ¹⁰⁹Cd concentration was 3.3‐fold greater in the kidneys. For virgin female mice over the same period, a relatively smaller shift was observed from remaining carcass to kidneys. Unlike breeders, ¹⁰⁹Cd content was identical in hepatic and renal tissues, while ¹⁰⁹Cd concentration was 4.6‐fold greater in the kidneys. With respect to renal ¹⁰⁹Cd increases, the larger portion of these shifts had occurred by the end of round 2 for virgin mice and by the end of round 6 for breeder mice. Comparison of content and concentration measures for a single, time‐matched, virgin male group with those from a virgin female group at the end of round 6 revealed distinguishable differences only for the mammary tissues; by either measure these were about threefold higher in the female one.