STUDIES OF 64Cu AND 109Cd EFFLUX AND UPTAKE IN MENKES KINKY HAIR (MKHS) FIBROBLASTS

Abstract

Previous studies in our laboratory indicated decreased efflux of Cu and abnormal metallothionein (MT1) in MKHS. To further identify the kinetics of these transport phenomena studies utilizing 64Cu and 109Cd were performed in MKHS and normal fibroblasts. MKHS and normal cells were grown in Cd-containing medium (Cd concentration = 1.5 μg/ml, 109cd concentration 0.15 μg/ml, spec. act. = 17.8 μCi/μg) for 20 hours, chased with non-radioactive medium and analyzed at 0, 5, 10, 20 hours. 60Cu efflux studies employed a 20 hour pulse (Cu concentration = 10 μg/ml, 64Cu concentration = 10 μg, sp. act. = 885 μCi/μg Cu) with chase intervals of 0, 5, 12, and 20 hours. These data clearly indicate a pronounced defect in the efflux of Cu in MKHS fibroblasts as compared to normal fibroblasts. The cadmium results suggest some impairment of Cd-release by MKHS fibroblasts. Studies by Goka et al. (Pediatr. Res.10:365, 1976) indicated increased uptake of 64Cu by MKHS fibroblasts. Our studies of 109cd uptake suggest nearly equivalent uptake by MKHS and normal fibroblasts (MKHS/normal = 0.9-1.8). These data imply that the observed apparent increased uptake is not the primary phenomenon.