Long retention times are seen in all tissues, despite tissue-specific differences in kinetics and final Cd concentrations, indicating a common high-affinity binding mechanism. When the power of this mechanism in different shark tissues is estimated as tissue:plasma ratios 7 days after tracer injection, binding in GZ and that in liver are equivalent (71:1 and 87:1, respectively) but not as powerful as in kidney (381:1). Even at the shallow end of the gradient, PoM-stage tissues are able to concentrate 109Cd to levels 18-fold higher than in plasma. Consistent with our results, testicular Cd accumulation is 5-fold lower in adult rats than in 4-day-old animals. Paradoxically, 109Cd accumulation in the adult rat testis is maximal in elongated spermatids, with spermatogonia showing only a very low incorporation. Cheap Diskus Advair
MT are a family of low molecular weight, cysteine-rich proteins that bind metal ions with high affinity. Several studies have reported a relationship between MT concentrations and differences in tissue, strain, and species in Cd-accumulation and -storage potentials. MT has been partially characterized in the liver of the spotted dogfish shark (Scyliorhinus), and trace amounts were detected in the testis.