Modulation of Endocrine Systems and Food Intake by Green Tea Epigallocatechin Gallate1

Yung-Hsi Kao, Richard A. Hiipakka, Shutsung Liao
2000 Endocrinology  
Green tea polyphenols, especially the catechin, (Ϫ)-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,
more » ... osterone, 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. (Endocrinology 141: 980 -987, 2000) Biochemical analysis For biochemical analysis, commercially available RIA kits for insulinlike growth factor I (IGF-I) and testosterone (Diagnostics Systems Laboratories, Inc., Webster, TX), LH and GH (Amersham Pharmacia Biotech, Arlington Heights, IL), leptin and insulin (Linco Research, Inc., St.
doi:10.1210/endo.141.3.7368 pmid:10698173 fatcat:a5lx3jdpjrczblf2dmnftf55tq