Induction of avidin synthesis by RNA obtained from chick oviduct.

Abstract

RNA was extracted from oviduct, shell gland, and liver of chicks treated with diethylstilbestrol and a combination of diethylstilbestrol and progesterone. Preparations containing 500 or 2500 mug of RNA were put in the oviductal lumen of diethylstilbestrol-treated chicks for 24 hr, and the avidin content of the oviduct was determined by measurement of [(14)C]biotin binding. The results of the present study demonstrate that oviduct RNA from chicks treated with progesterone induces synthesis of avidin in chick oviduct. In contrast, liver or shell gland RNA from chicks treated with progesterone, and liver or oviduct RNA from chicks treated with diethylstilbestrol are incapable of inducing avidin synthesis. The inducing capacity of oviduct RNA is destroyed when it is treated with ribonuclease. It is hypothesized that progesterone induces the synthesis of new species of oviduct RNA, which serve as messenger(s) for avidin synthesis. This hypothesis is offered in consideration of the findings: (i) that the residual amount of progesterone present as a contaminant in oviduct RNA from chicks treated with progesterone is far too low to account for the induced avidin synthesis; (ii) that such oviduct RNA from chicks treated with progesterone induces a slight synthesis of avidin in chick shell gland, which ordinarily does not produce avidin in response to progesterone administration and; (iii) that such RNA added in vitro to minces of oviductal tissues incubated in biotin-free medium for 24 hr induces synthesis of avidin.