T3 receptors in human pituitary tumors

Abstract

Objective: The purpose of this work was to investigate the synthesis of T3 receptors in human tumors of the anterior pituitary gland, its relationship with the hormone synthesized and/or secreted by the tumor and the post-surgical evolution of the patient. Methods: Patients were evaluated clinically and by magnetic nuclear resonance to classify the adenoma according to their size. Hormonal concentrations in sera were determined by radioimmunoassay. Immunohistochemistry of the pituitary hormones was performed in the tumors. Tumors were obtained at surgery and immediately frozen in ice, transported to the laboratory and stored at −70°C. Reverse transcription was performed with purified RNA from the tumors. Results: Out of 33 pituitary tumors, 29 had RNA for T3 receptors synthesis (88%). They were present in different histological specimens, the tumors were grades 1–4 according to their size, and there was no relationship between the size of the tumor and the presence of T3 receptor RNAs. The post-surgical evolution of the patient was mostly dependent on the size and not on the presence of T3 receptors. Discussion: The presence of thyroid hormone receptors in pituitary tumors is in line with two important characteristics of these tumors: they are histologically benign and well differentiated.