Effects of carnitine on thyroid hormone action.

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Effects of carnitine on thyroid hormone action.

http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve & db=pubmed &

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Benvenga S, Amato A, Calvani M, Trimarchi F.

Sezione di Endocrinologia, Dipartimento Clinico Sperimentale di Medicina e

Farmacologia, University of Messina School of Medicine, 98125 Messina, Italy.

s.benvenga

 

By experiments on cells (neurons, hepatocytes, and fibroblasts) that are

targets for thyroid hormones and a randomized clinical trial on iatrogenic

hyperthyroidism, we validated the concept that L-carnitine is a peripheral

antagonist

of thyroid hormone action. In particular, L-carnitine inhibits both

triiodothyronine (T3) and thyroxine (T4) entry into the cell nuclei. This is

relevant

because thyroid hormone action is mainly mediated by specific nuclear

receptors. In the randomized trial, we showed that 2 and 4 grams per day of oral

L-carnitine are capable of reversing hyperthyroid symptoms (and biochemical

changes

in the hyperthyroid direction) as well as preventing (or minimizing) the

appearance of hyperthyroid symptoms (or biochemical changes in the hyperthyroid

direction). It is noteworthy that some biochemical parameters (thyrotropin and

urine hydroxyproline) were refractory to the L-carnitine inhibition of thyroid

hormone action, while osteocalcin changed in the hyperthyroid direction, but

with a beneficial end result on bone. A very recent clinical observation proved

the usefulness of L-carnitine in the most serious form of hyperthyroidism:

thyroid storm. Since hyperthyroidism impoverishes the tissue deposits of

carnitine, there is a rationale for using L-carnitine at least in certain

clinical

settings.

 

PMID: 15591013 [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve & db=pubmed &

dopt=AbstractPlus & list_uids=15591013