The conversion of thyroxine to triiodothyronine in the lung: comparison of activity of type I iodothyronine 5' deiodinase in lung cancer with peripheral lung tissues.

Abstract

1. Conversion of T4 to T3 occurs also in the lung. 2. The activity of DI is statistically significantly lower, in lung cancer than in peripheral lung tissue (13.3 +/- 9.5 vs 22.20 +/- 13.4 pmol/min/mg protein) respectively, p < 0.001. 3. DII activity in lung is present and similar in peripheral lung and lung cancer tissue. 4. There is a non-significant trend for correlation of DI activity and grade of differentiation (G1-G3) of tumour tissue and stage of lung cancer. Abbreviations' list: T3--triiodothyronine, T4--thyroxine, FT4--free thyroxine, rT3--revers triiodothyronine TSII--Thyroid Stimulating Hormone Type I lodothyronine 5'deiodinase = type I 5'deiodinase = 5'DI = DI Type II Iodothyronine 5'deiodinase = typeII 5'deiodinase = 5'DII = DII E.S.S.--Euthyroid Sick Syndrome, hDII = human type II iodothyronine deiodinase HDII-b, hDII-c = two novel splice variants SCC--Squamous Cell Cancer, A--adenocarcinoma, BMI--Body Mass Index BSA--Bovine Standard Albumin, DTT-1,4 Dithio-L-treitol, PTU--Propylothiouracil TCA--Tricholoroacetic Acid, TNM--Tumour Nodule Metastases (class.) G1-G3-grade of differentiation, COPD--Chronic Obstructive Pulmonary Disease.