[Control of therapy for hyperthyroidism. Comparison of in-vitro and in-vivo methods]

55 patients with treated hyperthyroidism (thyreostatics) underwent a T3 suppression test and a TRH stimulation test. 60% of the patients had a positive and 40% a negative T3 suppression test. While patients with a positive T3 suppression test always showed a positive TRH test, the behaviour of the TRH test in negative suppression test was different (68.2% positive, 31.8% negative). These discrepant findings are to be explained from the establishment of different phases of regulation. In negative TRH test the concentrations of hormones were significantly higher. Increased basal TSH values are an expression of an overtreatment with thyreostatics. In positive suppression test and TRH test after a therapy lasting at least one year the medication can be stopped. In negative suppression test, however, the therapy should be changed. The TRH test allows only evidence about the quality of the regulation of therapy. Finally it can be established that the two tests on account of their different working points in the regulatory system are necessary and not changeable between each other.