Modulation of endocrine systems and food intake by green tea epigallocatechin gallate.
Green tea polyphenols, especially the catechin, (-)-epigallocatechin gallate (EGCG), have been proposed as a cancer chemopreventative based on a variety of laboratory studies. For clear assessment of the possible physiological effects of green tea consumption, we injected pure green tea catechins ip into rats and studied their acute effects on endocrine systems. We found that EGCG, but not related catechins, significantly reduced food intake; body weight; blood levels of testosterone, estradiol, leptin, insulin, insulin-like growth factor I, LH, glucose, cholesterol, and triglyceride; as well as growth of the prostate, uterus, and ovary. Similar effects were observed in lean and obese male Zucker rats, suggesting that the effect of EGCG was independent of an intact leptin receptor. EGCG may interact specifically with a component of a leptin-independent appetite control pathway. Endocrine changes induced by parenteral administration of EGCG may relate to the observed growth inhibition and regression of human prostate and breast tumors in athymic mice treated with EGCG as well as play a role in the mechanism by which EGCG inhibits cancer initiation and promotion in various animal models of cancer.
Kao
Y H
YH
Ben May Institute for Cancer Research, Department of Biochemistry and Molecular Biology, and Tang Center for Herbal Medicine Research, University of Chicago, Illinois 60637, USA.
Hiipakka
R A
RA
Liao
S
S
D000818:Animals; D001772:Blood Cell Count / Q000187:drug effects; D001774:Blood Chemical Analysis; D001835:Body Weight / Q000187:drug effects; D002392:Catechin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D004435:Eating / Q000187:drug effects*; D004702:Endocrine Glands / Q000187:drug effects*; D005260:Female; D005835:Genitalia / Q000187:drug effects; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011924:Rats, Zucker; D013662:Tea / Q000737:chemistry*; D013739:Testosterone / Q000378:metabolism / Q000494:pharmacology
D012739:Gonadal Steroid Hormones; D007328:Insulin; D020738:Leptin; D013662:Tea; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D002392:Catechin; D007986:Luteinizing Hormone; D013006:Growth Hormone; C045651:epigallocatechin gallate