PROTECTIVE ACTION OF ZINC AGAINST DELETERIOUS EFFECTS OF CADMIUM IN REGENERATING FORELIMB OF ADULT NEWT, NOTOPHTHALMUS-VIRIDESCENS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 41  (2) , 95-103
Abstract
Forelimbs of adult male newts (N. viridescens) were amputated and immediately dipped in cadmium nitrate for 2 min; in addition, some of the newts were injected with zinc chloride 24 h prior to or 24 h after amputation. Dipping the amputated forelimb of a newt in a solution of 0.4 M cadmium nitrate completely inhibited or retarded regeneration throughout the 65 days of observation. Other effects of Cd administration include erythema of the limb, an extensive protrusion of the humerus and in some cases atypical differentiation of regenerates. When zinc chloride was injected (0.04 mg/g of body wt) i.p. into the newt 24 h prior to limb amputation and Cd dipping, the deleterious effects of Cd treatment were prevented and normal regeneration occurred. When zinc chloride was administered 24 h after amputation and Cd dipping, it gave no protection against the Cd. Cd might inhibit regeneration through the inactivation of Zn metalloenzymes as a result of an exchange of Cd for Zn. Zinc chloride administered to newts prior to Cd treatment may prevent the replacement of Zn by Cd.