methylthiouracil and Brain-Neoplasms

The paper discusses the influence of deranged function of the thyroid (in postnatal period) on the transplacental carcinogenic effect of N-nitrosomethylurea (NMU) in albino noninbred rats. It was found that exogenous thyroxin-induced hyperthyroidism and thyroid function suppression either by long-term treatment with a thyreostatic agent--methylthiouracil (MTU) or thyroidectomy are followed by a lower frequency of, chiefly, nervous system tumors which are typical of NMU-induced transplacental carcinogenesis in rats. Moreover, transplacental treatment with NMU potentiated the carcinogenic effect of MTU on the thyroid. The latter manifested itself in a higher frequency of malignancies of the thyroid in animals exposed to a combined treatment with NMU (transplacentally) and MTU (postnatally) as compared with those given MTU only (postnatally).

Topics: Animals; Brain Neoplasms; Female; Maternal-Fetal Exchange; Methylnitrosourea; Methylthiouracil; Neoplasms, Experimental; Pregnancy; Rats; Thyroid Gland; Thyroid Neoplasms; Thyroidectomy; Thyroxine

Topics: Animals; Brain Neoplasms; Carcinogens; Estrogens; Female; Male; Methylthiouracil; Neoplasms, Experimental; Nitroso Compounds; Ovarian Diseases

Topics: Animals; Brain Neoplasms; Castration; Gonads; Male; Methylthiouracil; Neoplasms, Experimental; Nitroso Compounds; Radiation Effects; Rats