Increase in the beta subunit of human TSH in hypothyroid serum after thyrotropin releasing hormone.

Abstract

The beta subunit of human thyrotropin (hTSH-β) was detected in the serum of 9 of 11 patients with primary hypothyroidism. After the administration of thyrotropin releasing hormone (TRH), there was an increase in serum hTSH-β in all 11 patients. Five of the patients studied at multiple intervals after TRH showed an increase in hTSH-β as early as 5 minutes after TRH. HTSH-β rose more rapidly and reached a peak earlier than hTSH. The data suggest that hTSH-β is secreted in response to TRH in patients with primary hypothyroidism.