[Porphobilinogen biosynthesis from delta-aminolevulinic acid by the internal organs of white rats].

The capacity for porphobilinogen (PBG) biosynthesis from aminolevulinic acid (ALA) in the homogenates of the lung, heart, liver, kidney, pancreatic and small intestinal tissues of 77 albino rats was determined, and all the mentioned organs were found to be capable of PBG biosynthesis. The greatest ALA dehydratase activity was found in the tissue of the liver, then -- in the order of decreasing activity -- in the tissues of the kidneys, lungs, pancreas, small intestine, heart and spleen. On addition of lead solution to the synthesizing system a significant reduction in the activity of the enzyme was revealed in the tissue of the liver; the activity was unchanged in the kidney tissue. No changes in the toxic effect of lead were found on simultaneous addition of lead and D-penicillamine.