The Effect of Thyrotrophin-Releasing Hormone on Serum TSH, T₄, and T₃ Levels in Endemic and Sporadic Nontoxic Goitre[*]

Abstract

Serum TSH, T₄, T₃, GH and insulin have been assayed before and after the i.v. injection of 200 µg Thyrotrophin- Releasing Hormone (TRH) in three groups of persons: in 20 normal subjects, in 12 patients with nontoxic goitre from Ulm and in 5 patients with endemic goitre from Greece, In another 12 goitrous patients from Greece only the basal hormone level has been assayed. These 17 patients with endemic goitre had on average a lower serum T₄ level, higher T₃ values, and a higher TSH level (mean ± SE 21.29 ± 0.94 µU/ml) than the normal Ulm controls (p < 0.001). The group with sporadic nontoxic goitre from Ulm had low serum T₄, high T₃ but normal TSH values compared to the Ulm controls. Following TRH injection, in the controls the serum TSH rose from a basal value of 11.06 ± 2.17 µU/ml (mean ± SE) to a maximum of 25.30 ± 3.70 15 min later, after which there was a progressive fall. In the goitrous patients from Ulm serum TSH increased from 11.80 ± 2.43 to 35.75 ± 5.23 after 15 min. In the 5 patients so studied with iodine-deficiency endemic goitre from Greece the serum TSH rose from 21.3 ± 1.65 µU/ml to 37.70 ± 7.20 µU/ml at 15 min, remained high at 30 min, and then decreased progressively. The 15 min value was significantly higher than in the two german groups. There was no significant change in either the growth hormone or the insulin levels. It is concluded that serum TSH is often increased in nontoxic goitre, especially in the endemic areas, and that it rises more after TRH injection than in normal persons.

Goitre, Nontoxic, Endemic and Sporadic - Thyroid Hormones in Nontoxic Goitre - TRH in Nontoxic Goitre - TSH, Serum, in Nontoxic Goitre

1 Supported by the Deutsche Forschungsgemeinschaft, Bad Godesberg (R)-299/l), Research Grant No AM 07464 from the National Institutes of Health and a Research Grant from the Hellenic Ministry of Social Services.