Communications: Gentamicin Concentrations in Toadfish and Goldfish Serum

Abstract

Abstract Previous work in our laboratory has demonstrated that goldfish Carassius auratus produce new nephrons in response to gentamicin-induced nephrotoxicity. The oyster toadfish Opsanus tau, however, does not undergo nephron neogenesis. To explore possible reasons for the differences in the formation of new nephrons, we evaluated the elimination of gentamicin from the serum of both species. Fish (20 toadfish and 20 goldfish) were given intramuscular injections of 3.5 mg gentamicin/kg of body weight or an equal volume of sterile water. Blood samples were taken by venipuncture from goldfish at days 1, 2, 3, and 4 postinjection and from toadfish at days 1, 2, 7, 14, 28, and 49 postinjection. Gentamicin levels were measured in serum via a competitive binding immunoassay. Gentamicin levels in serum declined rapidly in goldfish, reaching near baseline levels 4 d after the injection, with a half-life of 49.6 h for the β component. Toadfish had a much longer gentamicin retention time with a half-life of 602 h ...