Fate of cadmium in rat renal tubules: a micropuncture study.
Free-flow micropuncture was carried out in superficial nephrons of Munich-Wistar type rats infused acutely with Cd acetate (CdA) or Cd-DTPA (141 microM Cd). Fluid obtained from Bowman's space (BS) or end-proximal tubule sites was analyzed for Cd and inulin. The fluid/plasma Cd concentration ratio in BS averaged 0.2 and 1.0 during CdA and Cd-DTPA infusions, respectively. End-proximal tubule fractional excretion of Cd during CdA infusion averaged 0.34. Previous administration of CdA (1.0 mg/kg, 48 hr before micropuncture) increased the level of circulating Cd-metallothioneins, as measured by radioimmunoassay, but did not affect the luminal tubular uptake of Cd during CdA infusion. No net transepithelial movement of Cd-DTPA was measured. It is concluded that Cd ultrafiltered during inorganic Cd administration is taken up to a large extent by the convoluted part of proximal tubules.
Felley-Bosco
E
E
Institut de Pharmacologie de l'Université, Lausanne, Switzerland.
Diezi
J
J
D000818:Animals; D002104:Cadmium / Q000493:pharmacokinetics*; D005260:Female; D007114:Immunization; D007684:Kidney Tubules / Q000378:metabolism*; D008668:Metallothionein / Q000032:analysis / Q000378:metabolism; D011677:Punctures; D011863:Radioimmunoassay; D051381:Rats; D014462:Ultrafiltration
D002104:Cadmium; D008668:Metallothionein