Thyroid growth modulating factors in the sera of patients with simple non-toxic goitre

Abstract

Since 'Thyroid-Growth-Immunoglobulins' are implicated in the pathogenesis of some goitrous thyroid diseases, we have investigated the presence of thyroid growth modulators in the sera from patients with simple non-toxic goitre (diffuse non-toxic goitre and colloid nodular goitre). To detect growth effect, two procedures were employed, both using [3H]thymidine incorporation into DNA. In one procedure, porcine thyroid follicles in suspension were employed. Gamma-globulin (2 mg/ml) from 10/26 of patients with diffuse non-toxic goitre and 8/27 of patients with colloid nodular goitre were found to increase [3H]thymidine incorporation when compared to gamma-globulins from control group. The other procedure used sparsely plated thyroid cells isolated from normal or porcine thyroid gland and from human simple non-toxic goitre. No serum from patients with simple goitre showed greater growth stimulating activity than that of normal individuals. Moreover, using simple goitre cells as target, a lower serum activity was observed in 7/28 of patients with diffuse non-toxic goitre and in 9/30 of patients with colloid nodular goitre. Analogous results were obtained with normal porcine thyroid cells. The lower serum activity of these patients was observed in a wide range of serum concentrations (1 to 15%) and was associated with and inhibitory effect recovered in the gamma globulin fraction. By the two different procedures, we have therefore evidenced the presence of thyroid growth modulators in the sera of several patients with simple non-toxic goitre. The stimulatory effect observed with the thyroid follicles strengthens the implication of thyroid growth stimulating immunoglobulin in the pathogenesis of some simple sporadic non-toxic goitre. The negative effect detected with monolayers of sparsely plated thyroid cells needs further characterization but, at least, it points out the importance of the culture conditions in the interpretation of the results.