SERUM AND URINE CONCENTRATIONS IN NICKEL-SENSITIVE PATIENTS AFTER PROLONGED ORAL-ADMINISTRATION

8 nickel-sensitive subjects were given a gradually increasing daily or al intake of NiSO4 in water. The exposure lasted from between 91 and 1 78 days and the total intake ranged from between 113 and 278 mg of Ni+. While 6 subjects were continuously exposed over the entire period, the other 2 were exposed for 2 shorter periods with an interval betwee n the 2 exposures of 84 and 63 days, respectively. Nickel exposure was well tolerated by all subjects, and there was no worsening of the cut aneous manifestations. Ni++ serum and urine concentrations were repeat edly assayed. A reduction of intestinal adsorption and an activation o f the renal excretion were shown through an evaluation of the ratios o f Ni++ serum concentration/Ni++ cumulative oral intake, Ni++ urinary a mount/nickel cumulative oral intake and Ni++ serum amount/Ni++ urine a mount. The course of Ni++ faecal amounts, calculated indirectly, incre ased rapidly in time and was consistent with the other courses. In man y subjects, the decrease in serum concentrations was followed by a sli ght increase. It is likely that this phenomenon is due to the release of epidermally stored nickel. These data seem to indicate that in some sensitive subjects, prolonged oral exposure to NiSO4 in water reduces the intestinal adsorption of nickel and activates its renal excretion , also promoting the mobilization of accumulated element. (C) Munksgaa rd, 1994.