Bruce D Weintraub | Search PubMed

PubMed2006

A comparison of short-term changes in health-related quality of life in thyroid carcinoma patients undergoing diagnostic evaluation with recombinant human thyrotropin compared with thyroid hormone withdrawal.

CONTEXT: Thyroid carcinoma requires lifelong monitoring with serum thyroglobulin, radioactive iodine whole body scanning, and other imaging modalities. Levothyroxine (L-T4) withdrawal for thyroglobulin measurement and whole body scanning increases these tests' sensitivities but causes hypothyroidism. Recombinant human TSH (rhTSH) enables testing without L-T4 withdrawal. OBJECTIVE: Our objective was to examine the impact of short-term hypothyroidism on the health-related quality of life (HRQOL) of patients after rhTSH vs. L-T4 withdrawal. DESIGN, SETTING, AND PATIENTS: In this multicenter study, the SF-36 Health Survey was administered to 228 patients at three time points: on L-T4, after rhTSH, and after L-T4 withdrawal. INTERVENTIONS: INTERVENTIONS included administration of rhTSH on L-T4 and withdrawal from thyroid hormone. MAIN OUTCOME MEASURES: Mean SF-36 scores were compared during the two interventions and with the U.S. general population and patients with heart failure, depression, and migraine headache. RESULTS: Patients had SF-36 scores at or above the norm for the general U.S. population in six of eight domains at baseline on L-T4 and in seven of eight domains after rhTSH. Patients' scores declined significantly in all eight domains after L-T4 withdrawal when compared with the other two periods (P < 0.0001). Patients' HRQOL scores while on L-T4 and after rhTSH were at or above those for patients with heart failure, depression, and migraine in all eight domains. After L-T4 withdrawal, patients' HRQOL scores were significantly below congestive heart failure, depression, and migraine headache norms in six, three, and six of the eight domains, respectively. CONCLUSIONS: Short-term hypothyroidism after L-T4 withdrawal is associated with a significant decline in quality of life that is abrogated by rhTSH use.

Female↗

PubMed2002

Thyroid-stimulating hormone and thyroid-stimulating hormone receptor structure-function relationships.

This review focuses on recent advances in the structure-function relationships of thyroid-stimulating hormone (TSH) and its receptor. TSH is a member of the glycoprotein hormone family constituting a subset of the cystine-knot growth factor superfamily. TSH is produced by the pituitary thyrotrophs and released to the circulation in a pulsatile manner. It stimulates thyroid functions using specific membrane TSH receptor (TSHR) that belongs to the superfamily of G protein-coupled receptors (GPCRs). New insights into the structure-function relationships of TSH permitted better understanding of the role of specific protein and carbohydrate domains in the synthesis, bioactivity, and clearance of this hormone. Recent progress in studies on TSHR as well as studies on the other GPCRs provided new clues regarding the molecular mechanisms of receptor activation. Such advances are a result of extensive site-directed mutagenesis, peptide and antibody approaches, detailed sequence analyses, and molecular modeling as well as studies on naturally occurring gain- and loss-of-function mutations. This review integrates expanding information on TSH and TSHR structure-function relationships and summarizes current concepts on ligand-dependent and -independent TSHR activation. Special emphasis has been placed on TSH domains involved in receptor recognition, constitutive activity of TSHR, new insights into the evolution of TSH bioactivity, and the development of high-affinity TSH analogs. Such structural, physiological, pathophysiological, evolutionary, and therapeutic implications of TSH-TSHR structure-function studies are frequently discussed in relation to concomitant progress made in studies on gonadotropins and their receptors.

Amino Acid Sequence↗