BACKGROUND: Some extra-thyroid effects of TSH have been described in vitro and in vivo. TSH has recently been suggested to induce interleukin-6 secretion by adipocytes. Leptin is the main protein secreted by adipose tissue. OBJECTIVE: The aim of our study was to evaluate the acute effect of the recombinant human TSH (rhTSH)-induced TSH surge on serum leptin levels in thyroidectomized patients undergoing levothyroxine (L-T4) suppressive therapy for differentiated thyroid carcinoma (DTC). DESIGN: A cohort of 15 female DTC patients was evaluated. Standard rhTSH testing was performed. Leptin, TSH, thyroid hormones, and thyroglobulin were measured before and 3, 6, and 9 days after rhTSH testing. Some metabolic parameters were also evaluated at the baseline. RESULTS: Baseline leptin levels were 12.2+/-3.2 microg/l. Only body mass index (BMI) correlated significantly (p<0.05) with leptin levels. After rhTSH administration, TSH levels increased significantly (p<0.001), while thyroid hormones remained unchanged. Twenty hours after the last rhTSH administration, leptin (11.8+/-3.0 microg/l) levels were unchanged. The maximal TSH level was negatively related with BMI (p<0.05), but no correlation between maximal TSH and leptin levels after rhTSH was noted. CONCLUSIONS: Our in vivo experimental model suggests that an acute TSH increase after rhTSH testing is ineffective in changing circulating leptin levels.
BACKGROUND: Some extra-thyroid effects of TSH have been described in vitro and in vivo. TSH has recently been suggested to induce interleukin-6 secretion by adipocytes. Leptin is the main protein secreted by adipose tissue. OBJECTIVE: The aim of our study was to evaluate the acute effect of the recombinant humanTSH (rhTSH)-induced TSH surge on serum leptin levels in thyroidectomized patients undergoing levothyroxine (L-T4) suppressive therapy for differentiated thyroid carcinoma (DTC). DESIGN: A cohort of 15 female DTCpatients was evaluated. Standard rhTSH testing was performed. Leptin, TSH, thyroid hormones, and thyroglobulin were measured before and 3, 6, and 9 days after rhTSH testing. Some metabolic parameters were also evaluated at the baseline. RESULTS: Baseline leptin levels were 12.2+/-3.2 microg/l. Only body mass index (BMI) correlated significantly (p<0.05) with leptin levels. After rhTSH administration, TSH levels increased significantly (p<0.001), while thyroid hormones remained unchanged. Twenty hours after the last rhTSH administration, leptin (11.8+/-3.0 microg/l) levels were unchanged. The maximal TSH level was negatively related with BMI (p<0.05), but no correlation between maximal TSH and leptin levels after rhTSH was noted. CONCLUSIONS: Our in vivo experimental model suggests that an acute TSH increase after rhTSH testing is ineffective in changing circulating leptin levels.
Authors: Michael Rosenbaum; Ellen M Murphy; Steven B Heymsfield; Dwight E Matthews; Rudolph L Leibel Journal: J Clin Endocrinol Metab Date: 2002-05 Impact factor: 5.958
Authors: Marina A Michalaki; Apostolos G Vagenakis; Aggeliki S Leonardou; Marianna N Argentou; Ioannis G Habeos; Maria G Makri; Agathoklis I Psyrogiannis; Fotis E Kalfarentzos; Venetsana E Kyriazopoulou Journal: Thyroid Date: 2006-01 Impact factor: 6.568
Authors: C E Tene Pérez; M C Revilla-Monsalve; D Amato; J Escobedo de la Peña; R Galván; R O Millán-Guerrero; B Trujillo Hernández; A Zárate; S Islas-Andrade Journal: Endocr Res Date: 2004-02 Impact factor: 1.720
Authors: M Giusti; R Zoccola; B Guazzini; E Molinari; S Valenti; G Villa; L Bertolazzi; F Minuto Journal: Minerva Endocrinol Date: 2003-09 Impact factor: 2.184