title: Acetyl-L-carnitine suppresses thyroid hormone-induced and spontaneous anuran tadpole tail shortening.
abstract: Mitochondrial membrane permeability transition (MPT) plays a crucial role in apoptotic tail shortening during anuran metamorphosis. L-carnitine is known to shuttle free fatty acids (FFAs) from the cytosol into mitochondria matrix for β-oxidation and energy production, and in a previous study we found that treatment with L-carnitine suppresses 3, 3', 5-triiodothyronine (T3 ) and FFA-induced MPT by reducing the level of FFAs. In the present study we focus on acetyl-L-carnitine, which is also involved in fatty acid oxidation, to determine its effect on T3 -induced tail regression in Rana rugosa tadpoles and spontaneous tail regression in Xenopus laevis tadpoles. The ladder-like DNA profile and increases in caspase-3 and caspase-9 indicative of apoptosis in the tails of T3 -treated tadpoles were found to be suppressed by the addition of acetyl-L-carnitine. Likewise, acetyl-L-carnitine was found to inhibit thyroid hormone regulated spontaneous metamorphosis in X. laevis tadpoles, accompanied by decreases in caspase and phospholipase A2 activity, as well as non-ladder-like DNA profiles. These findings support our previous conclusion that elevated levels of FFAs initiate MPT and activate the signaling pathway controlling apoptotic cell death in tadpole tails during anuran metamorphosis.
authors.affiliation: Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashihiroshima, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hanada
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Kobuchi
authors.forename: Masanao
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Katsu
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Utsumi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Junzo
authors.initials: J
authors.lastname: Sasaki
authors.forename: Masayasu
authors.initials: M
authors.lastname: Inoue
authors.forename: Kozo
authors.initials: K
authors.lastname: Utsumi
mesh_terms: D000108:Acetylcarnitine / Q000494:pharmacology*; D000818:Animals; D001001:Anura / Q000235:genetics* / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D007814:Larva; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects; D054467:Phospholipases A2 / Q000378:metabolism; D013623:Tail / Q000187:drug effects*; D013963:Thyroid Hormones / Q000494:pharmacology*
chemical_list: D013963:Thyroid Hormones; D000108:Acetylcarnitine; D054467:Phospholipases A2; D053148:Caspase 3; D053453:Caspase 9