[Experimental study of the correlation between function and morphology of rat thyroid after the application of methylthiouracil and thyroid stimulating hormone].

In an experimental study with 359 male Wistar rats the thyroid function was altered with MTU and TSH. The morphological changes developing due to this treatment were compared with the hormone blood level measured as labelled protein-bound iodine (PBI-127). Furthermore, the content of PBI-131 was determined and the I-131 uptake of the thyroid after application of TSH was measured. It was shown that with a dosis which had no influence on the PBI-127 and radioiodine values, the height of the thyroid epithelium already revealed a significant reaction. By a morphological examination together with the histometrical determination of the height of the thyroid epithelium the hormone-dependent increase in activity may be determined quantitatively.