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This Article Accepted manuscript (PDF) All Versions of this Article: EJE-08-0151v1 159/2/153    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Filipsson, H. Articles by Johannsson, G. Search for Related Content PubMed PubMed Citation Articles by Filipsson, H. Articles by Johannsson, G.

Exploring the use of recombinant human thyrotropin in the diagnosis of central hypothyroidism

H Filipsson, Endocrinology, Göteborg, S-413 45, Sweden
E Nystrom, Endocrinology, Göteborg, Sweden
G Johannsson, Endocrinology, Göteborg, Sweden

Correspondence: Helena Filipsson, Email: helena.filipsson{at}telia.com

Abstract

Objective: The diagnosis of central hypothyroidism (CH) is often difficult to establish as serum TSH levels may be low, normal or slightly increased. This study explored the use of recombinant human TSH (rhTSH) in the diagnosis of CH.

Design: Randomised single-blinded clinical trial.

Methods: A single intramuscular injection of 0.1 mg and 0.9 mg rhTSH in random order with one-week interval were given to 18 adult patients with pituitary insufficiency and six healthy age-, sex- and BMI-matched controls. Six patients had untreated CH (newCH), six had treated CH (CH) and six patients were TSH-sufficient (nonCH). Five weeks before TSH stimulation, levothyroxine was replaced with triiodothyronine for four weeks. One week before stimulation treatment was withdrawn. Thyroid hormones and thyroglobulin were measured before and 2, 3.5, 7, 24, 48 and 72 hours after each injection.

Results: In the newCH group, basal FT4 levels were lower than in controls (p<0.05). After 0.9 mg rhTSH, the increases in FT4 and rT3 were less marked in the newCH group than in controls (FT4+/-SEM 9.2+/-0.5 to 19.7+/-1.2 vs 11.3+/-0.5 to 27.8.2+/-2.4 pmol/L, p<0.05). The CH group exhibited reduced basal and stimulated FT4 compared with the TSH-sufficient groups. Thyroglobulin increased similarly among all study-groups after rhTSH injection.

Conclusion: In this pilot study patients with untreated CH had lower response to 0.9 mg rhTSH in FT4 and rT3 than controls. An rhTSH test may be useful in the diagnosis of CH, but further studies are required.