Quantitative development of the subcommissural organ in hypothyroid mice.

The postnatal development of the global volume of the subcommissural organ (SCO) and of the karyometric changes of the ependymocytes in the SCO and the adjacent ventricle is studied in male albino mice aged from 25 to 160 days, and in a hypothyroid group treated with propylthiouracil with and without interruption of the treatment at 35 days. Hypothyroidism produces a decrease of the global volume of the SCO and of the nuclear size of the ependymocytes in the SCO and the adjacent ventricle.