L-thyroxine and triiodo-L-thyronine in the cerebrospinal fluid and hypothalamo-hypophyseal axis of hyper- or hypothyroid rats

Abstract

L-thyroxine and triiodo-L-thyronine concentrations in cerebrospinal fluid (CSF), hypothalamus and pituitary gland are measured in male albino-Wistar rats under several experimental thyroid disfunction : including hyperthyroidism induced by L-T3 and L-T4 treatments and surgical hypothyroidism.Radioimmunoassay is carried out by Nejad's method modified in this work.The pattern of thyroid hormone concentrations in CSF is similar to that in serum, but the values obtained are lower.Thyroid hormone concentrations in adenohypophysis as opposed to hypothalamus or cerebral cortex, show an inverse change to functional thyroid status.