BACKGROUND: Ephedra, a Chinese medicine, is often used to treat obesity with relatively satisfying results recently. However, the effects of Ephedra on the perimenopausal and postmenopausal obese women remain unclear.OBJECTIVE: To observe the effects of oral Ephedra decoction on body mass and the levels of blood lipids, blood glucose and hormone in ovarietomized obese rats.DESIGN: A completely randomized and controlled experiment.SETTING: Institute of Physiology and Psychology, School of Basic Medical Sciences, Lanzhou University.MATERIALS: The experiment was performed in the Key Laboratory of Pre-clinical Study for New Drugs of Gansu Province and the Laboratory of Institute of Physiology and Psychology, School of Basic Medical Sciences,Lanzhou University from February 2006 to June 2006. Forty-four healthy female SD rats were randomly divided into four groups with 11 rats in each group, namely sham-operated group, ovariectomized group, estrogen replacement therapy group and Ephedra group.METHODS: ① After having been narcotized by cloraminone (110 mg/kg),rats were underwent a bilateral ovariectomy except those in the sham-operated group, which were also operated, but their ovaries were not cut off. ②Rats in the sham-operated group and ovariectomized group were subcutaneously injected with sesame oil (0.2 mL/each rat) every day postoperatively till the end of the experiment. ③ The rats in the estrogen replacement therapy group were given estradiol (1 mg/kg) by subcutaneous injection every day postoperatively till the end of the experiment. ④ The rats in the Ephedra group freely drank 1% water extracts from Ephedra postoperatively, later the concentration of Ephedra gradually increased to 8% on the sixth day, which lasted until the end of the experiment. ⑤ The food intake was monitored daily, and body mass was measured every ten days. ⑥ At the end of the experiment, all the rats were fasted for 12 hours and collected blood samples for the measurement of serum indexes. The body mass and body length were measured to calculate the Lee's index [(g)×103/body length (cm)] at the same time.MAIN OUTCOME MEASURES: ① Body mass and Lee's index at different time points in each group. ② Food intake at different time points in each group. ③ Levels of blood lipids and blood glucose in each group. ④Levels of estrogen, progesterone and insulin in each group.RESULTS: Forty-four rats all entered the analysis of results. ① Result of body mass and Lee's index at different time points: The body masses on the 20th, 30th, 40th and 50th days in the ovariectomized group were (256.4±14.3),(271.3±16.1), (276.4±12.7), (285.7±24.2) g, which were significantly higher than those in the sham-operated group [(226.5±11.5), (241.8±12.6),(243.1±13.5), (251.1±22.4) g, P ＜ 0.05-0.01], and the Lee's index in the ovariectomized group was greater than that in the sham-operated group(317.2±13.5, 280.4±11.2, P ＜ 0.01). The body masses on the 40th and 50th days in the estrogen replacement therapy group were (243.7±14.8) and(246.2±11.9) g, which were significantly lower than those in the ovariectomized group (P ＜ 0.05-0.01), and the Lee's index (289.9±13.5) was lower than that in the ovariectomized group (P ＜ 0.01). The body masses on the 40th and 50th days in the Ephedra group were (245.4 ±14.1) and(252.4±14.9) g, and the Lee's index was 294.4±11.0, which were all lower than those in the ovariectomized group (P ＜ 0.05). ② Result of Food in take at different time points: The food intakes on the 30th, 40th and 50th days in the Ephedra group were (17.8±2.4), (22.3±3.9), (26.1±3.5) g per day,which were decreased as compared with those in the ovariectomized group[(25.9±4.7), (28.5±5.3), (32.8±5.5) g per day, P ＜ 0.05]. ③ Levels of blood lipids and blood glucose: The levels of triglyceride, cholesterol and low density lipoprotein cholesterol (LDL-C) in the ovariectomized group were (1.73±0.32), (1.45±0.50), (0.78±0.19) mmol/L, which were higher than those in the sham-operated group [(0.94±0.29), (1.05±0.30), (0.08±0.11) mmol/L, P ＜ 0.01]. After the estrogen replacement therapy, the levels of triglyceride, cholesterol, LDL-C and blood glucose were (1.10±0.34),(1.14±0.30), (0.17±0.05), (5.88±1.21) mmol/L, which were lower than those in the ovariectomized group (P ＜ 0.05-0.01), but the level of high density lipoprotein cholesterol (HDL-C) was higher than that in the ovariectomized group [(1.11±0.31), (0.88±0.21) mmol/L, P ＜ 0.05]. The levels of triglyceride, cholesterol, LDL-C and HDL-C in the Ephedra group were (0.97±0.16), (1.11±0.20), (0.59±0.07) and (0.45±0.061) mmol/L, which were lower than those in the ovariectomized group (P ＜ 0.05-0.01). ④ The serum levels of estrogen, progesterone and insulin in each group: The serum levels of estrogen and progesterone in the ovariectomized group were lower than those in the sham-operated group [(17.09±9.00), (28.51 ±7.99) μg/L;(58.69±12.11), (62.73±10.93) μg/L, P ＜ 0.01], the serum level of insulin was higher than that in the sham-operated group [(31.74±6.69),(23.75±6.66) mU/L, P ＜ 0.01]. The serum levels of estrogen in the estro gen replacement therapy and Ephedra group were (36.03±8.83) and (30.18±8.61) ng/L, which were higher than those in the ovariectomized group(P ＜ 0.05-0.01), the level of insulin were (21.34±4.57), (24.86±6.20) mU/L,which were lower than those in the ovariectomized group (P ＜ 0.05-0.01).The serum level of progesterone in the Ephedra group [(17.68±6.19) μg/L]was lower than that in the ovariectomized group (P ＜ 0.01).CONCLUSION: Ephedra can promote loss of body mass, reduce levels of the blood lipids and insulin, and increase the serum levels of hormones in ovariectomized obese rats.