1. The induction of phase I and II enzymes in the liver of the male F3
44 rat drinking 2% (w/v) solutions of green or black tea for 6 weeks w
as investigated. Also studied were glutathione (GSH) and cyst(e)ine in
blood, liver and kidney, as well as serum cholesterol, HDL cholestero
l, triglycerides, and total and free testosterone. 2. The total carbon
monoxide-discernible liver P450, b(5) and NADPH-cytochrome c (P450) r
eductase activities were similar in all groups. 3. There were signific
ant increases in liver of rat drinking green or black tea of P4501A1,
1A2 and 2B1 activities, but no change in P4502E1 and 3A4 activities. O
f the phase II enzymes, UDP-glucoronyltransferase was increased, but g
lutathione S-transferase was not. 4. Serum GSH was higher in the group
administered black tea, but GSH and cyst(e)ine in other groups was at
control levels. Serum cholesterol was lower in rat given black compar
ed with green tea. Triglycerides had a declining trend after green and
black tea exposure compared with water controls. Free and total testo
sterone were not affected. 5. Thus, beverages widely used by man alter
ed host biochemistry as regards specific phase I and II enzymes in liv
er of rat and specific serum parameters.