Abstract
Background
Roux-en-Y gastric bypass (RYGB) modifies the anatomical structure of the upper intestine tract, reduces gastric acid secretion, and may impair LT4 absorption. The aim of this study was to evaluate the LT4 absorption in morbidly obese patients before and after RYGB.
Methods
Thirty morbidly obese patients were divided in two groups: The NS group included 15 patients before RYGB surgery (BMI = 43.1 ± 4 kg/m2), and the S group included 15 patients after surgery (BMI = 37.3 ± 4 kg/m2). Two baseline samples were collected, and 600 μg of oral LT4 tablets were administered. Blood samples were collected at 30, 60, 120, 180, 240, 300, and 1440 min. Serum-free T4 (FT4), total T4 (TT4), and TSH were measured at each time point. The increase in TT4, FT4, and TSH (ΔTT4, ΔFT4, and ΔTSH) was calculated, subtracting from the baseline mean value.
Results
The pharmacokinetics parameters regarding LT4 absorption, maximum ΔTT4, and area under the curve(AUC) of both ΔTT4 and ΔFT4 were significantly higher in the S group compared with the NS group (p < 0.05). It was observed, however, that there was a significant delay in the absorption of LT4 in the S group. Basal serum TSH and leptin levels were higher in the NS group (p = 0.016 and 0.026, respectively), whereas basal serum TT4, FT4, ΔTSH, and the AUC of ΔTSH were similar between groups.
Conclusions
In this study, we have demonstrated that Roux-en-Y bypass surgery does not diminish LT4 absorption. A small but significant delayed absorption of LT4, however, was observed in patients after surgery.
Similar content being viewed by others
References
Chen AY, Jemal A, Ward EM. Increasing incidence of differentiated thyroid cancer in the United States, 1988–2005. Cancer. 2009;115:3801–7.
Camargo RY, Tomimori EK, Neves SC, et al. Thyroid and the environment: exposure to excessive nutritional iodine increases the prevalence of thyroid disorders in Sao Paulo, Brazil. Eur J Endocrinol. 2008;159:293–9.
Aoki Y, Belin RM, Clickner R, et al. Serum TSH and total t4 in the United States population and their association with participant characteristics: National Health And Nutrition Examination Survey (NHANES 1999–2002). Thyroid. 2007;17:1211–23.
Papavramidis ST, Zisiadis AC, Karamouzis MN, et al. Alterations in thyroid hormones and thyrotropin (TSH) in morbidly obese patients before and after vertical gastroplasty. Obes Surg. 1995;5:298–301.
Marzullo P, Minocci A, Tagliaferri MA, et al. Investigations of thyroid hormones and antibodies in obesity: leptin levels are associated with thyroid autoimmunity independent of bioanthropometric, hormonal, and weight-related determinants. J Clin Endocrinol Metab. 2010;95:3965–72.
Sherman SI, Malecha SE. Absorption and malabsorption of levothyroxine sodium. Am J Ther. 1995;2:814–8.
Liel Y, Sperber AD, Shany S. Nonspecific intestinal adsorption of levothyroxine by aluminum hydroxide. Am J Med. 1994;97:363–5.
Northcutt RC, Stiel JN, Hollifield JW, et al. The influence of cholestyramine on thyroxine absorption. JAMA. 1969;208:1857–61.
Sherman SI, Tielens ET, Ladenson PW. Sucralfate causes malabsorption of l-thyroxine. Am J Med. 1994;96:531–5.
Campbell NR, Hasinoff BB, Stalts H, et al. Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism. Ann Intern Med. 1992;117:1010–3.
Singh N, Weisler SL, Hershman JM. The acute effect of calcium carbonate on the intestinal absorption of levothyroxine. Thyroid. 2001;11:967–71.
McLean M, Kirkwood I, Epstein M, et al. Cation-exchange resin and inhibition of intestinal absorption of thyroxine. Lancet. 1993;341:1286.
Benvenga S, Bartolone L, Pappalardo MA, et al. Altered intestinal absorption of l-thyroxine caused by coffee. Thyroid. 2008;18:293–301.
Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8:667–71.
Centanni M, Gargano L, Canettieri G, et al. Thyroxine in goiter, helicobacter pylori infection, and chronic gastritis. N Engl J Med. 2006;354:1787–95.
Checchi S, Montanaro A, Pasqui L, et al. L-thyroxine requirement in patients with autoimmune hypothyroidism and parietal cell antibodies. J Clin Endocrinol Metab. 2008;93:465–9.
Benvenga S, Bartolone L, Squadrito S, et al. Delayed intestinal absorption of levothyroxine. Thyroid. 1995;5:249–53.
Hays MT, Nielsen KR. Human thyroxine absorption: age effects and methodological analyses. Thyroid. 1994;4:55–64.
Santini F, Pinchera A, Marsili A, et al. Lean body mass is a major determinant of levothyroxine dosage in the treatment of thyroid diseases. J Clin Endocrinol Metab. 2005;90:124–7.
Mistry D, Atkin S, Atkinson H, et al. Predicting thyroxine requirements following total thyroidectomy. Clin Endocrinol (Oxf). 2011;74:384–7.
Zaninotto P, Head J, Stamatakis E, et al. Trends in obesity among adults in England from 1993 to 2004 by age and social class and projections of prevalence to 2012. J Epidemiol Community Health. 2009;63:140–6.
Decker GA, Swain JM, Crowell MD, et al. Gastrointestinal and nutritional complications after bariatric surgery. Am J Gastroenterol. 2007;102:2571–80. quiz 2581.
Hays MT. Localization of human thyroxine absorption. Thyroid. 1991;1:241–8.
Hennemann G, Docter R, Friesema EC, et al. Plasma membrane transport of thyroid hormones and its role in thyroid hormone metabolism and bioavailability. Endocr Rev. 2001;22:451–76.
Wenzel KW, Kirschsieper HE. Aspects of the absorption of oral l-thyroxine in normal man. Metabolism. 1977;26:1–8.
Bevan JS, Munro JF. Thyroxine malabsorption following intestinal bypass surgery. Int J Obes. 1986;10:245–6.
Azizi F, Belur R, Albano J. Malabsorption of thyroid hormones after jejunoileal bypass for obesity. Ann Intern Med. 1979;90:941–2.
Kok P, Roelfsema F, Langendonk JG, et al. High circulating thyrotropin levels in obese women are reduced after body weight loss induced by caloric restriction. J Clin Endocrinol Metab. 2005;90:4659–63.
Flier JS, Harris M, Hollenberg AN. Leptin, nutrition, and the thyroid: the why, the wherefore, and the wiring. J Clin Invest. 2000;105:859–61.
Hollenberg AN. The role of the thyrotropin-releasing hormone (TRH) neuron as a metabolic sensor. Thyroid. 2008;18:131–9.
Acknowledgments
We are grateful to the patients who have consented to undergo LT4 absorption tests. We also want to express our gratitude to Suzimara A. de Oliveira from The Central Laboratory, Valeria Samuel Lando from the Endocrine Laboratory (LIM 42) for conducting the thyroid function tests and leptin measurements, and to Aché Laboratórios Farmacêuticos S.A. for the supply of LT4 tablets (Levoid®).
Disclosure Summary
This work was partially funded by a research grant from Aché Laboratórios Farmacéuticos S.A. to Fundação Faculdade de Medicina São Paulo, Brazil, a non-profit organization. A partial grant was also received from Instituto da Tiróide (São Paulo), also a non-profit organization. The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rubio, I.G.S., Galrão, A.L., Santo, M.A. et al. Levothyroxine Absorption in Morbidly Obese Patients Before and After Roux-En-Y Gastric Bypass (RYGB) Surgery. OBES SURG 22, 253–258 (2012). https://doi.org/10.1007/s11695-011-0452-8
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11695-011-0452-8