Distribution, excretion and metabolism of lead in guinea pigs

In vivo experiments were undertaken to study the distribution as well as the toxic effects of lead on male guinea pigs, Cavia porcellia. The administration of 664 mg Pb+2/kg [which represents the 96 hours LD50, orally induced the bioaccumulation of this heavy metal in various tissues in the following order: kidney >liver >bone >blood >brain. Lead administration induced its excretion by both the urinary and fecal routes. A decrease in the blood iron concentration and increases in copper, zinc and calcium levels in the blood were noticed after lead intoxication. Lead induced malformations in the RBCs and a decrease in their number. It also caused decreases in the hemoglobin content and hematocrit value. On the other hand, neither the mean corpuscular volume [MCV] nor the mean corpuscular hemoglobin concentration [MCHC] were changed. Increases in the activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and amylase, were indicated in the plasma as a result of lead toxicity. However, acetyl cholinesterase activity decreased. Total bilirubin, glucose level, total lipids, total cholesterol, urea, uric acid and creatinine in the plasma were increased. While liver glycogen was decreased. On the other hand, total phospholipid and triglyceride concentrations in the plasma were not changed. These results were discussed in detail

Notes on the treatment of acute lead poisoning with zinc or sodium calcium edetate in guinea pigs

Studies have been carried out on the ability of either zinc or sodium calcium edetate to offset the acute toxicity of lead. The 96 hr LD50 for the oral administration of lead was found to be 664 mg Pb+2/kg b.wt. The minimal concentration of the intramuscular injected Zn+2 with prevented lead induced lethality was found to be 0.1 mg/kg, while the minimal dose of the injected sodium calcium edetate which prevented lead induced lethality was 2 mg/kg b.wt. The results indicate that although the therapeutic dose of zinc retained lead in the body and caused some side-effects, it was able to prevent any change in the functions of liver and to reduce lead-brain concentration to the control level. It also alleviated the undesirable effects in the renal and pancreatic functions. Similarly, although sodium calcium edetate therapy induced some side effects, it increased the urinary excretion of lead which leads to the reduction of this metal in all the studied tissues and organs. It also abolished the perturbations in the studied hematological parameters and the kidney functions as well as the total bilirubin, glucose levels and the activity of acetylcholinesterase which were induced in the plasma. It also alleviated the disturbances in the liver functions