THE INVOLVEMENT OF THE PENTOSE SHUNT IN THYROID METABOLISM AFTER STIMULATION WITH TSH OR WITH IMMUNOGLOBULINS FROM PATIENTS WITH THYROID DISEASE. 1. THE GENERATION OF NADPH IN RELATION TO STIMULATION OF THYROID GROWTH

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Abstract
It has been shown that TSH, and also Ig derived from patients with goitrous Graves'' disease, stimulate DNA synthesis in guinea pig thyroid tissue maintained in vitro. This experiment describes the use of the same in vitro system and methods of quantitative cytochemistry to test the effect of these substances on the generation of NADPH, which is another indicator of the potential for growth. As could be predicted by its trophic action, TSH stimulated the generation of NADPH by glucose 6-phosphate dehydrogenase. The Ig fraction from normal subjects depressed this activity. The Ig fraction from Graves'' disease patients with goiters stimulated the generation of NADPH; the Ig from patients with Graves'' disease but with minimal enlargement of the thyroid gland behaved like normal Ig. A similar lack of stimulation was found with Ig from patients with Pendred''s syndrome, other dyshormonogenetic goiters, and autonomous single adenomas. In all specimens tested, there was good correlation between the amount of DNA synthesis, measured by Feulgen cytophotometry, and the activity of glucose 6-phosphate dehydrogenase activity that generated NADPH. Apparently there is a distinct type of autoantibody that influences thyroid growth.