title: Muscle carnitine in hypo- and hyperthyroidism.
abstract: Weakness is common in both hyper- and hypothyroidism, and skeletal muscle L-carnitine may play a role in this regard, as suggested by studies indicating abnormal levels of carnitine in serum and urine of patients with thyroid dysfunction. Skeletal muscle samples were obtained for carnitine analysis from control subjects, and from hyperthyroid and hypothyroid patients before and after treatment. There was a significant reduction in carnitine, especially the esterified portion, in hyperthyroid individuals, with a return to normal as euthyroid status was regained. In hypothyroid patients, there was a trend for carnitine to be lower than normal and for improvement once euthyroid status was attained. Our data indicate that muscle carnitine levels are affected by both hypo- and hyperthyroidism. A decrease in muscle carnitine in both conditions may contribute to thyroid myopathy.
authors.affiliation: Department of Neurology, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sinclair
authors.forename: James M
authors.initials: JM
authors.lastname: Gilchrist
authors.forename: James V
authors.initials: JV
authors.lastname: Hennessey
authors.forename: Manju
authors.initials: M
authors.lastname: Kandula
mesh_terms: D000328:Adult; D001706:Biopsy; D002331:Carnitine / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D007037:Hypothyroidism / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000503:physiopathology; D009135:Muscular Diseases / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D002331:Carnitine