Inhibition of glucocorticoid-induced cataracts in chick embryos by RU486: A model for studies on the role of glucocorticoids in development

Effect of antithyroid drug on chick embryos during the last week of development: Delayed hatching and decreased cerebellar acetylcholinesterase activity

“…We contend that the ‘fertilized hen's egg‐chick embryo‐chick system’ is a useful animal model for investigating the direct roles of hormones during embryogenesis 18,19,28–30 because chick embryos develop in the absence of maternal influences: they could be administered stressors, including chemical and physical insults, at any time during embryogenesis, and once the hatched chicks could walk, their behavior could be easily observed.…”

Effects of glucocorticoid on brain acetylcholinesterase of developing chick embryos

“…One can use chemicals such as metyrapone, which is an inhibitor of the 11β‐hydroxylase enzyme required for GC biosynthesis or a specific GR antagonist such as mifepristone 14–16 . We selected mifepristone for the experiments in the present studies because of our past experiments showing its preventive effects on cataract formation caused by GC 18,20 …”

“…(ii) Our previous results showed that administration of GC on day 15 elevated the levels of blood glucose and lipids, 18,19 and produced cataracts and suppressed bone growth. These phenomena could be suppressed by mifepristone 20 . (iii) Cholinesterases, including AChE, have been studied extensively and an increase in AChE activity with embryonic age was observed 21–23 .…”

Inhibition of glucocorticoid-induced changes of Na+, K+-ATPase in rat lens by a glucocorticoid receptor antagonist RU486

“…Receptor specificity was determined by a specific GC antagonist, RU486.Therefore RU486 provides a way to evaluate receptor-mediated events in the steroid induced cataract [56,57]. It can inhibit Dex-induced decrease in receptor activity [57,58].…”