Preparation of (13)C-labeled ceramide by acetic acid bacteria and its incorporation in mice.
We prepared 2-hydroxypalmitoyl-sphinganine (dihydroceramide) labeled with a stable isotope by culturing acetic acid bacteria with (13)C-labeled acetic acid. The GC/MS spectrum of the trimethylsilyl derivative of (13)C-labeled dihydroceramide gave molecular ions with an increased mass of 12-17 Da over that of nonlabeled dihydroceramide. The fragment ions derived from both sphinganine base and 2-hydroxypalmitate were confirmed to be labeled with the stable isotope in the spectrum. Therefore, (13)C-labeled dihydroceramide can be an extremely useful tool for analyzing sphingolipid metabolism. The purified [(13)C]dihydroceramide was administered orally to mice for 12 days, and the total sphingoid base fractions in various tissues were analyzed by GC/MS. The spectrum patterns specific to (13)C-labeled sphingoids were detected in the tissues tested. Sphinganine pools in skin epidermis, liver, skeletal muscle, and synapse membrane in brain were replaced by [(13)C]sphinganine at about 4.5, 4.0, 1.0, and 0.3%, respectively. Moreover, about 1.0% of the sphingosine pool in the liver was replaced by [(13)C]sphingosine, implying that exogenous dihydroceramide can be converted to sphingosine. These results clearly indicate that ingested dihydroceramide can be incorporated into various tissues, including brain, and metabolized to other sphingolipids.
Fukami
Hiroyuki
H
Central Research Institute, Mizkan Group Corporation, Handa, Aichi, Japan. h-fukami@mizkan.co.jp
Tachimoto
Hideki
H
Kishi
Mikiya
M
Kaga
Takayuki
T
Waki
Hatsue
H
Iwamoto
Machiko
M
Tanaka
Yasukazu
Y
D019342:Acetic Acid / Q000378:metabolism*; D000091:Acetobacter / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D002247:Carbon Isotopes; D002518:Ceramides / Q000008:administration & dosage / Q000096:biosynthesis* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007553:Isotope Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D002247:Carbon Isotopes; D002518:Ceramides; C109343:dihydroceramide; D019342:Acetic Acid