Effects of p,p'-DDE and some other chlorinated hydrocarbons on the formation of prostaglandins by the avian eggshell gland mucosa

Abstract

Some structurally related chlorinated hydrocarbons were investigated for their effects on the production of prostaglandins by the eggshell gland mucosa of ducks and domestic fowl. Formation of PGF2 alpha, PGE2 and TxB2 by homogenates of domestic fowl eggshell gland mucosa was significantly inhibited by in vitro addition of p,p'-DDE, Arochlor 1242 and, to a lesser extent, Arochlor 1260, but not by p,p'-DDT and o,p'-DDE. Comparatively, in duck eggshell gland mucosa homogenates, synthesis of the same prostaglandins was somewhat more sensitive to inhibition by 5 microM p,p'-DDE added in vitro. Eggshell gland mucosa synthesized significantly more PGF2 alpha, PGE2 and TxB2 than did the mucosa of the magnum and isthmus regions of the oviduct. Duck eggshell gland mucosa homogenates synthesized significantly more prostaglandins than similar homogenates from the domestic fowl, and, considering the former synthesis of PGF2 alpha was significantly higher when ducks were slaughtered at 08:00 than at 16:00 hours. In ducks, dietary administration of 40 ppm, p,p'-DDE for 45 days resulted in 21% eggshell thinning compared to the contemporary control values. This treatment also resulted in notable effects in homogenates of the eggshell gland mucosa, as compared to controls: Ca2+ uptake was reduced by 43%, synthesis of PGF2 alpha, PGE2 and TxB2 was reduced by 26%, 38% and 53%, respectively; the Ca content was increased to 145%. The role of p,p'-DDE in inhibiting prostaglandin formation in the eggshell gland is discussed as a mechanism of the eggshell thinning action of this chlorinated hydrocarbon.