Type 1 iodothyronine deiodinase (D1) is responsible for the conversion of thyroxin (T4) into tri-iodothyronine (T3). The enzyme is mainly present in thyroid, liver and kidneys.
There is strong evidence that the metabolism of thyroid hormones is disturbed in some neoplasmatic tissues. However there are only few available data about D1 enzymatic activity in liver tumors.
The aim of this study was to estimate the enzymatic activity of D1 in metastases of large intestine carcinoma in comparison with healthy liver tissue. The activity was assessed by measurement of radioactive iodine released in reaction of deiodination catalyzed by D1.
Twenty-two tumors and twenty-two healthy control tissues, obtained from the patients (average age 61) operated because of second deposits in liver, were examined. It was found that D1 activity was significantly lower in metastatic tissues in comparison with healthy counterparts (P<0.0001).
This finding demonstrates low enzymatic activity of D1 in large intestine metastases into liver and suggest so far unknown role of thyroid hormones in this type of liver tumors.
03 - 07 May 2008
European Society of Endocrinology