Studies on functional and morphological aspects in human multinodular simple goiter tissues

Samples from 2 different locations within the same euthyroid multinodular goiters (SMG) and normal (N) human thyroids were assayed for their content of DNA, thyroglobulin (Tg), and stable iodine (¹²⁷1), and determined the response of adenosine 3',5'-cyclic monophosphate (cAMP) to TSH and NaF. Quantitative morphological estimation of histological components in the thyroid was performed and correlated with functional parameters. Regardless the zonal evaluation, in SMG the mean (± SD) DNA content (⧎g/mg tissue) (1.04 ± 0.86) was not statistically different from that in N (1.13 ± 0.21). The mean¹²⁷I concentration (⧎g/⧎g DNA) in N tissues (0.357 ± 0.091) was greater than that in SMG (0.176 ± 0.074). In these tissues, the Tg mean level (± SD) (⧎g/⧎g DNA) was lower (28.3 ± 21.5) than that in N (75.6 ± 41.1). The mean relative proportion (Vv) of epithelial cells in SMG (range, 6.0-30.6%) was statistically different (p <0.00) from that observed in N tissues (range, 10.4-18.2%). The meanbasal (± SD) cAMP level (pmol/⧎g DNA) in these tissues (0.11 1 ± 0.036) was different (p < 0.05) from that in SMG (0.231 ± 0.026). In response to TSH (10 mU), both SMG and N increased their cAMP contents to 0.454 ± 0.045 and 0.572 ± 0.020, respectively. A further elevation in cAMP levels was observed in N (1.154 ± 0.210) after 75 mU TSH, whereas in SMG tissues, no consistent increase (0.609 ± 0.496) occurred. Goiter and normal thyroid slices were unable to increase their cAMP concentrations in response to NaF in vitro. No correlation was found between functional and morphological data in SMG samples. In contrast, this relation was quite uniform in normal thyroids. The results are concordant with the intrathyroidal pathogenic processes often cited for the heterogeneity in human goiter.