This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by LEE, H.-Y. Articles by HERSHMAN, J. M. Search for Related Content PubMed PubMed Citation Articles by LEE, H.-Y. Articles by HERSHMAN, J. M.

Secretion of Thyrotropin with Reduced Concanavalin-A-Binding Activity in Patients with Severe Nonthyroid Illness^*

Endocrine and Intensive Care Sections and Endocrine Research Laboratory, Wadsworth Veterans Administration Medical Center, University of California School of Medicine Los Angeles, California 90073

Address all correspondence and requests for reprints to: Jerome M. Hershman, M.D., Endocrinology, Wadsworth Veterans Administration Medical Center-WlllD, Wilshire and Sawtelle Boulevards, Los Angeles, California 90073.

Patients with nonthyroid illness (NTI) often have reduced serum T₃, free T₃) T₄, and free T₄ concentrations. Paradoxically, serum TSH is usually in the normal range. The data suggest a diagnosis of hypothalamic hypothyroidism, in which TSH may have reduced biological activity because TRH, which is necessary for key steps in the glycosylation of TSH, is deficient. To study the glycosylation of TSH in patients with NTI, we measured the serum TSH concentration in 36 such patients hospitalized on our intensive care units and compared the results with those from a group of 18 normal subjects. Serum TSH was measured in 2 assays: 1) a sensitive TSH RIA of unextracted serum (TSH-RIA) and 2) a RIA of serum TSH after its extraction with Concanavalin-A (Con-A), a lectin which binds glycoproteins containing mannose residues in their oligosaccharide side-chains (TSH-Con-A). The ratio of TSH-Con-A to TSH-RIA was significantly reduced in the NTI patients [0.61 ± 0.03 (±SE) vs. 0.89 ± 0.05 in the normal subjects] due to reduced binding of the TSH to the Con-A. This change was not dependent on the extent of the abnormalities of thyroid hormone levels. The data suggest that the TSH secreted in NTI has altered glycosylation which is associated with reduced biological activity. This finding may explain in part the low serum T₄ level in NTI patients in the face of an apparently normal immunoreactive TSH level.

^* This work was supported by V.A. Medical Research Funds.

Received March 12, 1987.

This article has been cited by other articles:

				M. P. Wajnrajch, J. M. Gertner, Z. Huma, J. Popovic, K. Lin, P. C. Verlander, S. D. Batish, P. F. Giampietro, J. G. Davis, M. I. New, et al. Evaluation of Growth and Hormonal Status in Patients Referred to the International Fanconi Anemia Registry Pediatrics, April 1, 2001; 107(4): 744 - 754. [Abstract] [Full Text] [PDF]

				L. J. De Groot Dangerous Dogmas in Medicine: The Nonthyroidal Illness Syndrome J. Clin. Endocrinol. Metab., January 1, 1999; 84(1): 151 - 164. [Full Text]

				R. Wang, J. C. Nelson, and R. B. Wilcox Salsalate Administration--A Potential Pharmacological Model of the Sick Euthyroid Syndrome J. Clin. Endocrinol. Metab., September 1, 1998; 83(9): 3095 - 3099. [Abstract] [Full Text]

				I. J. Chopra Euthyroid Sick Syndrome: Is It a Misnomer? J. Clin. Endocrinol. Metab., February 1, 1997; 82(2): 329 - 334. [Full Text] [PDF]