Preferential effect of lead exposure during lactation on non-essential fatty acids in maternal organs

This study determined the effects of lead exposure during the lactational period on maternal organ FA compositions in rat dams that were fed either an n-3 adequate (n-3 Adq) or deficient (n-3 Def) diet prior to conception. On giving birth, dams were subdivided into four groups in a 2 x 2 design with n-3 FA supply and Pb exposure as the dependent variables. Pb acetate (0.2 wt%) was administered in the drinking water from the time they gave birth to weaning 3 wk later. Following weaning, the dams were decapitated, and the liver, plasma, kidney, brain, and retina analyzed for FA composition. The n-3 deficient diets markedly decreased the percentages of total n-3 FA, including docosahexaenoic acid (DHA), and increased total n-6 FA including both arachidonic (AA) and n-6 docosapentaenoic acids in all tissues (P < 0.05). The principal effects of Pb occurred in the liver and plasma, where 20-32% losses in total FA concentration concurrent with increased relative percentages of AA (P < 0.05) were observed. In kidney, the percentages of AA and DHA also increased after Pb exposure (P < 0.05) with lesser effects in the nervous system. There was a diet x Pb interaction for liver, plasma, and retinal 20-C n-6 PUFA (P < 0.05). Generally, shorter-chain saturated and monounsaturated FA concentrations were decreased after Pb exposure. An analysis of the changes in the tissue concentrations induced by Pb indicated that the increases in the percentages of PUFA likely reflected a preferential loss of non-EFA. The mechanisms by which Pb affects saturated and monounsaturated FA concentration are unknown.