This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map 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 Valcavi, R. Articles by Dieguez, C. Search for Related Content PubMed PubMed Citation Articles by Valcavi, R. Articles by Dieguez, C. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB LEVOTHYROXINE METHIMAZOLE

Influence of Thyroid Status on Serum Immunoreactive Leptin Levels¹

Second Division of Internal Medicine, Section of Endocrinology and Metabolism, Hospital S. Maria Nuova, Reggio Emilia, Italy; the Department of Medicine, Endocrine Area, Complejo Hospital (R.P., F.F.C.), and the Department of Physiology (C.D.), University of Santiago, Santiago de Compostela, Spain

Address all correspondence and requests for reprints to: Dr. C. Dieguez, P.O. Box 563, 15780 Santiago de Compostela, Spain.

Leptin, the product of the ob gene, is a recently discovered hormone secreted by adipocytes. Serum leptin concentrations increase in correlation with the percentage of body fat, but besides that, little is known about the physiological actions of leptin in humans. The aim of this study was to assess the influence of hypo- and hyperthyroidism on serum leptin levels.

Thirty-two patients (16 with hypothyroidism and 16 with hyperthyroidism) were studied before and after treatment with replacement doses of T₄ (hypothyroid patients) or methimazole (hyperthyroid), when thyroid function was normal. Control serum for each group was obtained from healthy age-, sex-, and body mass index-matched subjects. Plasma leptin levels were measured by specific RIA.

The mean leptin level in the hypothyroid patients was lower before treatment (4.7 ± 0.7 µg/L) than that in the controls (8.6 ± 1.4 µg/L; P < 0.02) and was lower than that during treatment with T₄ and normalization of thyroid function in the same group of patients (6.3 ± 0.8 µg/L; P < 0.05). Leptin levels in the hyperthyroid patients were similar before (7.2 ± 1.1 µg/L) and after normalization of thyroid function following treatment with methimazole (6.2 ± 1.1 µg/L) and were similar to the control value (8.8 ± 1.4 µg/L).

In conclusion, leptin levels are decreased in the hypothyroid patients and unchanged in hyperthyroidism. Whether decreased leptin levels may contribute to the decreased energy expenditure in patients with hypothyroidism merits further investigation.

This article has been cited by other articles:

				G. Dimitriadis, P. Mitrou, V. Lambadiari, E. Boutati, E. Maratou, D. B. Panagiotakos, E. Koukkou, M. Tzanela, N. Thalassinos, and S. A. Raptis Insulin Action in Adipose Tissue and Muscle in Hypothyroidism J. Clin. Endocrinol. Metab., December 1, 2006; 91(12): 4930 - 4937. [Abstract] [Full Text] [PDF]

				H. Pijl, P. H. E. M. de Meijer, J. Langius, C. I. G. M. Coenegracht, A. H. M. van den Berk, P. K. Chandie Shaw, H. Boom, R. C. Schoemaker, A. F. Cohen, J. Burggraaf, et al. Food Choice in Hyperthyroidism: Potential Influence of the Autonomic Nervous System and Brain Serotonin Precursor Availability J. Clin. Endocrinol. Metab., December 1, 2001; 86(12): 5848 - 5853. [Abstract] [Full Text] [PDF]

				L. Ghizzoni, G. Mastorakos, M. Ziveri, M. Furlini, A. Solazzi, A. Vottero, and S. Bernasconi Interactions of Leptin and Thyrotropin 24-Hour Secretory Profiles in Short Normal Children J. Clin. Endocrinol. Metab., May 1, 2001; 86(5): 2065 - 2072. [Abstract] [Full Text]

				J.-L. Wang, N. Chinookoswong, S. Yin, and Z.-Q. Shi Calorigenic actions of leptin are additive to, but not dependent on, those of thyroid hormones Am J Physiol Endocrinol Metab, December 1, 2000; 279(6): E1278 - E1285. [Abstract] [Full Text] [PDF]

				A. M. Isidori, F. Strollo, M. Morè, M. Caprio, A. Aversa, C. Moretti, G. Frajese, G. Riondino, and A. Fabbri Leptin and Aging: Correlation with Endocrine Changes in Male and Female Healthy Adult Populations of Different Body Weights J. Clin. Endocrinol. Metab., May 1, 2000; 85(5): 1954 - 1962. [Abstract] [Full Text]

				S. S. Damjanovic, M. S. Petakov, D. Micic, J. Marinkovic, C. Dieguez, F. F. Casanueva, and V. Popovic Serum Leptin Levels in Patients with Acromegaly before and after Correction of Hypersomatotropism by Trans-Sphenoidal Surgery J. Clin. Endocrinol. Metab., January 1, 2000; 85(1): 147 - 154. [Abstract] [Full Text]

				M. Ozata, I. C. Ozdemir, and J. Licinio Human Leptin Deficiency Caused by a Missense Mutation: Multiple Endocrine Defects, Decreased Sympathetic Tone, and Immune System Dysfunction Indicate New Targets for Leptin Action, Greater Central than Peripheral Resistance to the Effects of Leptin, and Spontaneous Correction of Leptin-Mediated Defects J. Clin. Endocrinol. Metab., October 1, 1999; 84(10): 3686 - 3695. [Abstract] [Full Text] [PDF]

				C. S. Mantzoros The Role of Leptin in Human Obesity and Disease: A Review of Current Evidence Ann Intern Med, April 20, 1999; 130(8): 671 - 680. [Abstract] [Full Text] [PDF]

				M. P. Warren, F. Voussoughian, E. B. Geer, E. P. Hyle, C. L. Adberg, and R. H. Ramos Functional Hypothalamic Amenorrhea: Hypoleptinemia and Disordered Eating J. Clin. Endocrinol. Metab., March 1, 1999; 84(3): 873 - 877. [Abstract] [Full Text]

				G. Van den Berghe, P. Wouters, L. Carlsson, R. C. Baxter, R. Bouillon, and C. Y. Bowers Leptin Levels in Protracted Critical Illness: Effects of Growth Hormone-Secretagogues and Thyrotropin-Releasing Hormone J. Clin. Endocrinol. Metab., September 1, 1998; 83(9): 3062 - 3070. [Abstract] [Full Text]

				S.R. Bornstein, D.J. Torpy, G.P. Chrousos, J. Licinio, and L. Engelmann Leptin Levels Are Elevated Despite Low Thyroid Hormone Levels in the "Euthyroid Sick" Syndromei J. Clin. Endocrinol. Metab., December 1, 1997; 82(12): 4278 - 4279. [Full Text] [PDF]