Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9882173 | Archives of Biochemistry and Biophysics | 2005 | 11 Pages |
Abstract
Primary cultures of chick embryo hepatocytes have been used to study the mechanisms by which various drugs and other chemicals cause accumulation of porphyrin intermediates of the heme pathway. When these cultures are incubated with the heme precursor, 5-aminolevulinic acid (ALA), there is a major accumulation of protoporphyrin. However, in the presence of ALA, addition of insulin caused a striking increase in accumulation of uroporphyrin I and coproporphyrin III, whereas addition of glucagon mainly caused an increase in uroporphyrin I. Treatment with both insulin and glucagon resulted in additive increases in uroporphyrin, but not coproporphyrin. Antioxidants abolished the uroporphyrin I accumulation and increased coproporphyrin III. Insulin caused an increase in uptake of ALA and an increase in porphobilinogen accumulation, suggesting that the accumulation of uroporphyrin I is due to increased flux through the heme pathway. Apparently, this increased flux could particularly affect the utilization of the intermediate hydroxymethylbilane, which would result in accumulation of uroporphyrin I.
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Authors
Heidi W. Trask, Nadia Gorman, Barney E. Dwyer, Nicholas J. Jacobs, Judith M. Jacobs, Jacqueline F. Sinclair, Dominic Balestra, Peter R. Sinclair,