Effect of Zinc Deficiency on Prostaglandin Synthesis in Different Organs of the Rat

Abstract

Zinc has been implicated in regulation of some aspects of prostaglandin (PG) metabolism. Effects of zinc deficiency on PG synthesis and secretion were examined. Weanling rats were fed a control (adequate in zinc) or a zinc-deficient diet for 30 days. A third group was pair-fed to the zinc-deficient group with the control diet. The rats were anesthetized with ether, and tissues were excised for analysis. Zinc concentrations were measured in plasma, gut contents, gut mucosa, liver, lung and tibia. Prostaglandins F_2α, E₁, E₂, thromboxane B₂ (TXB₂), 6-keto PGF_1α (metabolite of PGI₂, met I₂) and 13,14-dihydro-15-keto PGF_2α (met F_2α) were measured by radioimmunoassay. The results indicate that, with the exception of gut contents, in most organs studied and for most PG measured, food restriction is as effective in reducing PG level as zinc deficiency. In the gut contents, however, there was a positive correlation between zinc and PGE₁ concentrations, and zinc deficiency decreased PGE₁, PGF_2α and PGI₂ metabolite levels beyond food restriction. The decrease in PG concentrations of gut contents without any change in their mucosal concentrations suggests an active process of PG secretion involving zinc. In addition, in serum from clotted blood, zinc deficiency increased the level of met F_2α (P < 0.05), suggesting that zinc might be involved in control of PG levels by changing PG degradation rate.