Hormonal manipulation and neonatal imprinting of carbonic anhydrase isozymes in rat liver.

Thyroidectomy has a feminizing effect on the carbonic anhydrase isozymes II and III in male rat liver. These isozymes are known to be sexually differentiated but no treatment so far administered has produced total feminization and this is also true for thyroidectomy. Neonatal castration, however, does produce this result, suggesting the possibility of androgen imprinting for these isozymes during the neonatal period.