9-cis beta-carotene in human plasma and blood cells after ingestion of beta-carotene.
For 44 wk, thirty male volunteers were given daily either 60 mg of synthesized all-trans beta-carotene, a naturally-occurring beta-carotene derived from Dunaliella bardawil, or a placebo. Basal levels of 9-cis beta-carotene in plasma, platelets, and mononuclear cells were 10, 20, and 25% of those of the all-trans form, respectively. The plasma levels reached a maximum after two weeks of administration and plateaued thereafter in the subjects who took the beta-carotene preparations. The all-trans beta-carotene level in the subjects given the synthesized all-trans form was almost twice that for the Dunaliella preparation. The plasma 9-cis level was found to be higher in the all-trans beta-carotene group than in the Dunaliella group, despite no intake of the 9-cis form in the all-trans group and the higher intake of the 9-cis form in the Dunaliella group. This finding suggests that isomerization of the all-trans form to the 9-cis form may occur in the body either during or after absorption.
Tamai
H
H
Department of Pediatrics, Osaka Medical College, Japan.
Morinobu
T
T
Murata
T
T
Manago
M
M
Mino
M
M
D000328:Adult; D001792:Blood Platelets / Q000378:metabolism; D002338:Carotenoids / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D004912:Erythrocytes / Q000378:metabolism; D056890:Eukaryota / Q000737:chemistry*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D013237:Stereoisomerism; D019207:beta Carotene
D019207:beta Carotene; D002338:Carotenoids