Secretion of nickel in rabbit saliva

Secretion of nickel into unstimulated and stimulated saliva of rabbits was studied after a single intraperitoneal injection of nickel chloride labelled with 63Ni. Maximum 63Ni in unstimulated saliva was obtained in specimens collected one hr after maximum serum-63Ni was reached and two hrs after the nickel administration. Compared to serum-63Ni, the secretion of isotope into saliva was low whether or not stimulation was carried out. After 24 hrs, only traces of radioactivity were left in saliva. Forty to 60 percent of salivary-63Ni was ultrafiltrable. Most nickel associated with salivary proteins was weakly bound. Two acidic protein fractions obtained by gel filtration of saliva seemed to bind nickel firmly at neutral pH. No such binding of nickel to salivary proteins was observed after the in vitro addition of normal saliva to 63NiCl2.