Interactions of cadmium with interstitial tissue of the rat testes. Uptake of cadmium by isolated interstitial cells.
Previous studies have shown that the administration of cadmium causes extensive necrosis of the testes and, eventually, a high incidence of interstitial cell tumors. However, the interactions of cadmium with interstitial cells of the testes have not been well defined. Therefore, this study was designed to assess the uptake of cadmium into this potential target cell of cadmium carcinogenesis. Interstitial cells were prepared by collagenase dispersion of decapsulated Wistar rat testes and separated from seminiferous tubules by unit gravity sedimentation. Such preparations showed a high exclusion rate of trypan blue. The interstitial cell preparations were incubated at 33 degrees with various concentrations of cadmium (1.0 to 100 microM) for periods ranging from 0.5 to 60 min. At the end of the incubation, cellular cadmium was separated from cadmium in the media by centrifugation through an oil layer. Initial experiments showed three distinct phases of cadmium influx into interstitial cells, a primary rapid velocity phase (V0; 0 to 1.5 min), a second intermediate velocity phase (V1; 3 to 12 min), and a third low velocity phase (V2; 15 to 60 min). V2 appeared to have both influx and efflux components, as efflux experiments indicated an approximate 20% loss of cadmium from 15 to 60 min. The initial phase was found to be nonsaturable and was not decreased by inclusion of potassium cyanide (1.0 mM), N-ethylmaleimide (1.0 mM), or zinc (100 microM) in the incubation mixture. However, V1 was found to be saturable between 50 and 100 microM cadmium and was substantially decreased by the inclusion of potassium cyanide, N-ethylmaleimide or zinc during incubation. These data suggest that cadmium is taken up into interstitial cells by a transport system that may normally function in zinc uptake and may possibly constitute carrier mediated or active transport.
D000818:Animals; D002104:Cadmium / Q000378:metabolism*; D066298:In Vitro Techniques; D007985:Leydig Cells / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D015032:Zinc / Q000494:pharmacology
D002104:Cadmium; D015032:Zinc