Regulation of avidin accumulation by prostaglandins in chick oviduct culture

Abstract Regulation of avidin accumulation by prostaglandins (PGs) and their inhibitors was studied in chick oviduct organ culture. Avidin was induced neither by progesterone nor PGF 2α in the oviduct of immature chicks. By progesterone and PGs, a high avidin synthesis was induced when the chicks received diethylstilbestrol (DES) for 7 days. Enhanced avidin production was observed by PGF 2α , PGE 1 and PGE 2 , whereas PGA 2 and PGB 2 had a slight inhibitory effect and PGA 1 and PGB 1 had no effect on avidin production. PGF 2α was most effective at a concentration of 10–20 μg/ml. The effects of progesterone and PGF 2α were not additive. Mefenamic acid, at concentrations of 40 and 60 μg/ml, inhibited 50 and 85%, respectively, of the avidin synthesis induced by progesterone, whereas the inhibition of the total protein synthesis was only 20%, and this only by the higher concentration of the drug. Tolfenamic and meclofenamic acid were also inhibitory in the case of progestin-induced avidin synthesis. These studies indicate that the PGs (F 2α , E 1 and E 2 ) might be involved in the avidin induction in the chick differentiated oviduct. The specific inhibition of the progesterone-dependent avidin synthesis by the PG inhibitors suggests that PGs may be connected with the progesterone action in the oviduct. We propose that the avidin synthesis by the chick oviduct might be considered as a model system for studying PG effects on the synthesis of a specific protein.