| Co-Investigator(Kenkyū-buntansha) |
OHISHI Nahoko SAme as above, Assistant (Instructor), 家政学部, 助手
KOGA Nobuyuki Same as above, Assoc. Professor, 家政学部, 助教授 (80136514)
KATO Sachiko Same as above, Assoc. Professor, 家政学部, 助教授 (70069780)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1995: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
(1) Commercial canned beverages (coffee, green tea, oolong tea, black tea and tochu tea) were given ad libitum to male Wistar rats for 20 and 10 days and killed at the next day. Using liver microsomes prepared from these rats, effects of the beverages on cytochrome P450 isozymes were studied.
(2) Caffeine contents (mg/100 ml) in the beverages were estimated to be 34.0 (coffee), 14.1 (green tea), 19.4 (oolong tea), 14.3 (black tea) and 0.0 (tochu tea). Taking into account the ingested volumes of the beverages (about 25 ml/day/body), daily intake of caffeine per body in the coffee-group was calculated to be about 8 mg.
(3) Contents of (-) epicatechin, (-) epicatechin gallate, (-) epigallocatechin and (-) epigallocatechin gallate in each of the canned beverages (green tea, oolong tea and black tea) varied considerably with the lot, but the total amounts were estimated to be 13 to 26 mg/100 ml.
(4) Amount of daily intake of each beverage was almost same as that of control, but the body weight
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gain of the coffee-and tochu tea-groups were suppressed significantly after 20 days experiment as compared with that of control.
(5) In the coffee-groups of 20 and 10 days experiments, activities of 7-ethoxy-resorufin O-deethylation, acetanilide hydroxylation and testosterone 6beta-hydroxylation were significantly increased in parallel with increase of cytochrome P450, suggesting a probable induction of P4501A and 3A subfamilies. significant decrease of benzphetamine N-demethylation sctivity in the coffee-groups suggested also a probable decrease of content of the constitutive P4502C11, considering a tendency to decrease activities of testosterone 2alpha-and 16alpha-hydroxylations.
(6) These changes of liver enzyme activities mediated by cytochrome P450 are consideaed to be induced mainly by caffeine, but the caffeine-free beverages also showed some inductive effect. This suggests that the epicatechins may have caffeine-like inducing ability, but the conclusive evidence supporting this assumption has not yet been obtained. Less
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