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Human thyroid stimulating activity in 37 patients with juvenile hyperthyroidism was studied during the course of antithyroid drug treatment. Observation periods varied from 6 months to 6 years (average 3 years). The existence of human thyroid stimulator (HTS) in their sera was determined by triiodothyronine (T3) release from resected thyroid adenomas. A measurement of T3 above the control value of 140% was judged to be positive. Before treatment, 25 of the 28 patients with Graves' disease had HTS in their sera, one of the 7 patients with Hashimoto's thyroiditis had HTS, and none of the 19 normal children had HTS in their sera. During the therapy, 7 of 18 Graves' patients had HTS. After cessation of the therapy, 9 of 22 patients remained HTS-positive, and 8 of the 9 patients with positive HTS relapsed within 6 months, whereas in 13 HTS-negative patients, 3 escaped and 10 remained in remission. There was no significant correlation between human thyroid stimulating activity (HTSA) and the following: serum T3 concentration, 131I-thyroidal uptake, TSH responsiveness to TRH and antithyroid antibody titre. These results indicate that (1) almost all patients with Graves' disease have HTS when they are ina state of hyperthyroidism, (2) HTS tends to disappear with the clinicial remission, but its persistence seems to predict relapse in the future, and (3) routine laboratory tests cannot serve as alternative to HTS.

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Summarydeiodinating system through NADPH-GSH cycle. In the present study, we attempted to elucidate the changes in the two pathways The role of NADPH and glutathione (GSH) in hepatic thyroxine during maturation, and the role of NADPH and GSH in the (~4 ) 5'deiodination and possible metabolic linkage between T4 hepatic conversion of T4 to T3, by sequential determination of converting system and hexose monophosphate shunt were studied the activity of glucose-6-phosphate dehydrogenase (G6PD) (EC in young rats during maturation. activity of T4 s'd-deiodinase 1.1.1.49), glutathione reductase (GSSG-R) (EC 1.6.4.2), T4 5'-in young rats was enhanced 2-Qfold with the addition of 1 mM deiodinase and the content of GSH and glycogen in liver.NADPH and GSH in vitro, the effect of which was more prominent with NADPH than with GSH. The highest enhancement was observed at 2-3 wk of age, whereas basal T4 5'-deiodinase activity MATERIALS AND METHODS was gradually increased until 5-6 wk of age, decreasing to adult level thereafter. hi^ change was associated with a rise in csH Pregnant Wistar rats were provided with commercial rat chow and glycogen content in the liver and significantly correlated to and water ad libitum. On the 21-22nd day of pregnancy, '-I3 the changes in glutathione reductase activity (,. = 0.622, < pups were delivered from each rats. Five to eight rats from 0.00~). In contrast, glucos~phosphate dehydrogenase (G6pD) different litters were used as the source of liver at weekly intervals activity remained depressed until 5 wk of age and rose sharply up to 7 wk of age. Maternal rats served as control. Under ether thereafter. B~~~~~ T4 5,deiodinase and G6PD activities after 6 anesthesia, the liver was removed, weighed and homogenized in wk of age, an inverse correlation was noted (r = -0.749, P < 0.01).ice phosphate buffer (pH 7.0) A doseresponse relationship between triiodothyronine (T3) pro-5 mM EDTA with Teflon homogenizer. After centrifugation at duction and NADPH in vitro showed similar agerelated changes, 3000 vm for min at 40C, the supernatant was whereas dosedependency of T3 formation on GSH was decreasing used for the assays except for protein and glycogen with age, especially under the presence of 1 mM NADPH.analysis. NADP, NADPH, GSH, GSSG, glycogen, G6P, T4 and These results indicate that: (1) NADPH and GSH are important T3 were purchased from Sigma Co. cofactors of T4 conversion to T3; (2) NADPH appears to be more T4 assay. The was determined the ratelimiting in the maturational process of the system; and (3) method of C h o p (10) under the presence or the absence of I hexose monophosphate shunt plays a significant role in the regu-mM NADPH7 mM GSH and a combination of both in each lation of T4 9-monodeiodination through NADPH and GSH sample. On each assay, duplicated samples of liver homogenate formation.from an adult female rat or those from maternal rat after weaning (3 wk postpartum) were settled as control. One ml of assay mixture contained 400 pl of 20% liver homogenate, 100 p1 of T4 (10 p...