Biomaterial Database

Secretion of thyrotropin with reduced concanavalin-A-binding activity in patients with severe nonthyroid illness. 1987

H Y Lee, and J Suhl, and A E Pekary, and J M Hershman

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

UI	MeSH Term	Description	Entries
D008171	Lung Diseases	Pathological processes involving any part of the LUNG.	Pulmonary Diseases,Disease, Pulmonary,Diseases, Pulmonary,Pulmonary Disease,Disease, Lung,Diseases, Lung,Lung Disease
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D003208	Concanavalin A	A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.
D006331	Heart Diseases	Pathological conditions involving the HEART including its structural and functional abnormalities.	Cardiac Disorders,Heart Disorders,Cardiac Diseases,Cardiac Disease,Cardiac Disorder,Heart Disease,Heart Disorder
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D013959	Thyroid Diseases	Pathological processes involving the THYROID GLAND.	Disease, Thyroid,Diseases, Thyroid,Thyroid Disease