DIETARY LEAD ALTERS FATTY-ACID COMPOSITION AND MEMBRANE PEROXIDATION IN CHICK LIVER-MICROSOMES

Inorganic Pb acetate is a pro-oxidant, and peroxidation damage to cell ular membrane lipids, leading to membrane fragility and permeability, is a likely consequence of Pb poisoning. In addition to the systemic p eroxidation that occurs in vivo, Pb-contaminated feedstuffs can contri bute preformed peroxides. Treatments with dietary Pb that hare been sh own to increase tissue peroxide levels in animals may be related to th e consumption of preformed peroxides from the diet; Ln the current stu dy, we evaluated the possible separate effects of feed and systemic pe roxides by administering equivalent doses of Pb acetate-trihydrate to chicks via either 1,500 ppm Pb in the diet or via gastric intubation. Peroxidation of Lipids in hepatic microsomal membranes (assessed as ma lonyldialdehyde production) from birds intoxicated with Pb by either r oute of administration was more than double that of untreated controls . Also, both routes of Pb exposure doubled the concentration of hepati c microsomal arachidonic acid, a peroxidizable polyunsaturated fatty a cid. In the data reported here, we show that tissue peroxide levels ar e unaffected by the method of oral. Pb administration and thus, by inf erence, independent of peroxide content of the feed.