[Data on the biochemical significance of nickel]

Pharmacokinetics of nickel chloride (63Ni) in blood and cerebral structures in male Wistar Rats is studied. After intravenous administration of 100 microCi 63 Ni, the trace element is distributed after an open bicompartmental model with a high alfa deposition constant, and the point obtained at 20 min. is considered in phase alfa. The kinetics of 63Ni in cerebral structures after the intracerebroventricular administration shows that hypocampus is the structure that most quickly reaches its maximal concentration. Mesencephalon shows slower penetration. Hypothalamus and hypocampus present greater accumulation of the radionucleide as compared with cortex and cerebellum which present a minor one. Insulin secretion of isolated and perfused rat pancreas from animals ingesting nickel in drink water after the stimulus with 16.7 mM glucose, is greater (53,35 ng immunoreactive insulin/min) than in control animals (30,42 ng immunoreactive insulin/min). In in vivo experiments, after a stimulus with 0,5 g glucose/Kg rat, for the 200 micrograms Ni/ml drinking water and control groups, there was an insulin secretion of 14 microunits insulin/ml and 2 microunits insulin/ml respectively. The normal plasmatic levels of insulin do not show any difference in both, nickel drinking water and controls. Nickel ion in drinking water induces the accumulation of calcium and zinc by the rat pancreas from 2.7 to 4 micrograms/mg protein and from 0.8 to 1.3 micrograms mg protein respectively. Both ions are essential cations for pancreatic physiological function and the synthesis of insulin.