Arginine vasotocin in the rabbit subcommissural organ.

Subcommissural organs of young and mature rabbits were analyzed for their content of arginine vasotocin by radioimmunoassay. Younger animals had significantly greater quantities of this peptide. There was no detectable arginine vasopressin or oxytocin in subcommissural organ extracts. It is concluded that the subcommissural organ represents, in addition to the pineal and the fetal neurohypophysis, another significant source of arginine vasotocin in the mammalian central nervous system.