Abstract
Specific glucocorticoid receptors from chick embryonic neural retina are demonstratable as early as 6 days in ovo. The receptor also binds progesterone with high affinity. Despite marked increases in glucocorticoid-provoked glutamine synthetase activity after Day 6, no increase in cytoplasmic receptor concentration occurs. Thus control of enzyme induction does not seem to depend simply on the presence of cytoplasmic steroid receptors but seems to be mediated by steps subsequent to the initial binding of hormone to receptor.
