The hypothalamus-pituitary-thyroid axis was studied in rats with the “low T3 syndrome” caused by the implantation of the Walker-256 mammary carcinoma. Male adult rats were injected s.c. with 1 x 106 viable tumoral cells and killed 10 days later. The tumor development was associated with decreased thyroid activity characterized by a ~15% reduction in the nuclear area of the thyrocytes and 131I-thyroid uptake (down by ~50%), as well as about 70% lower serum levels of T4 and rTg. The functional […]