Abstract
We have heard many studies that the pineal gland is the endocrine organ which controls the function of the sexual hormone and especially is well-known to be attended with a precocity at the time of pineal-tumour. Prof. Y. Tokumitsu has emphasized from many experiments that the deficiency states of the endocrine gland are not only caused by the lack of these hormones, but principally by the positive functional expression of other glands. Accordingly, as the writer has doubt on the cause of the precocity after pinealectomy that the hypertrophy of the sexual gland is brought by the disappearance of the control-hormone, he has attempted to do the followiag experiments.
First of all he has injected every day the serum of the male rabbit which has shown the hypertrophy and the early development of the genitalis over 20 days after pinealectomy, into the cocks. Consequently in the ear vein of that animal he has found an active substance which accelerates the development of the chicken's testicle and cockscomb and the appearance of secondary sexual character. This substadce has no action in the castrated cocks, and as it is insolub'e in organic solvent, it is not a sexual-hormone. This substance disappears from the blood of the hypophysectomized rabbit after pinealectomy, but as it does not vanish from the blood of the castrated, thyroidectomized, suprarenalectomized or thymusectomized rabbits, it is thought that this is produced from the pituitary gland. When two pituitary glands are transplanted from the pinealectomized rabbit, a similar active substance appears in the blood. And even if normal three pituitary glands are transplanted to the normal rabbit, the same active substance appears in the blood.
From the above experiments, it is evident that the hypertrophy of the sexual glands after pinealectomy and the attending precocious phenomena are caused by the hyperfunction of the pituitary gland in which gonadotropic hormone and growth-accelerating hormone are secreted in large quantities.
