Thyroid stimulating hormone (TSH) is produced by the pituitary gland and regulates the production of thyroid hormones. High or low levels of TSH can indicate thyroid dysfunction.
Thyroid hormones increase carnitine excretion. Low thyroid function and high TSH may increase carnitine retention.
Salvatore Benvenga, Rosaria M. Ruggeri, Antonia Russo, Daniela Lapa, Alfredo Campenni, Francesco Trimarchi. Usefulness of l-Carnitine, A Naturally Occurring Peripheral Antagonist of Thyroid Hormone Action, in Iatrogenic Hyperthyroidism: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial. The Journal of Clinical Endocrinology & Metabolism (2001). https://doi.org/10.1210/jcem.86.8.7747
Salvatore Benvenga, Rosaria M. Ruggeri, Antonia Russo, et al.. Thyroid hormones increase carnitine excretion: a true situation of secondary carnitine deficiency. The Journal of Clinical Endocrinology & Metabolism (2001). https://academic.oup.com/jcem/article/86/8/3579/2848640
Hari Krishnamurthy, Karthik Krishna, Tianhao Wang, John J. Rajasekaran, Karenah Rajasekaran, Vasanth Jayaraman, Swarnkumar Reddy, Xiaorong Song, and Vijay R. Rajasekaran. Effect of Micronutrients on Thyroid Parameters - PMC - NCBI. NCBI (2021). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8820928/
Coupling reaction: TPO combines iodinated tyrosine residues to make triiodothyronine (T3) and tetraiodothyronine (T4). MIT and DIT join to form… Physiology, Thyroid Hormone - StatPearls - NCBI Bookshelf. StatPearls (2023). https://www.ncbi.nlm.nih.gov/books/NBK500006/