OBJECTIVE: To study the differential effects of subcutaneous E2 alone or in combination with P on the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation in naturally postmenopausal diet-controlled rhesus monkeys. DESIGN: Prospective, longitudinal controlled study. SETTING: Oregon Health Sciences University, Portland, Oregon, and Oregon Regional Primate Research Center, Beaverton, Oregon. PATIENT(S): Five naturally postmenopausal rhesus monkeys. INTERVENTION(S): Estradiol was administered subcutaneously for the first 4 weeks, followed by E2 plus P for 4 weeks, followed by a third 4-week washout period. MAIN OUTCOME MEASURE(S): Changes in plasma lipoprotein levels and oxidation of LDL and serum concentrations of E2 and P. RESULT(S): Levels of LDL cholesterol fell after 4 weeks of treatment with E2, compared with baseline. The lag time to half maximal light absorbancy after 4 weeks of E2 treatment was significantly increased compared with baseline. The maximal absorbance values and the slope of the propagation phase after 4 weeks of treatment with E2 were decreased compared with baseline. After 4 weeks of combined E2 and P treatment, all values were comparable to baseline. CONCLUSION(S): These results suggest that subcutaneous E2 therapy appears to enhance LDL resistance to oxidation and that this effect is attenuated by the addition of the P.
OBJECTIVE: To study the differential effects of subcutaneous E2 alone or in combination with P on the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation in naturally postmenopausal diet-controlled rhesus monkeys. DESIGN: Prospective, longitudinal controlled study. SETTING: Oregon Health Sciences University, Portland, Oregon, and Oregon Regional Primate Research Center, Beaverton, Oregon. PATIENT(S): Five naturally postmenopausal rhesus monkeys. INTERVENTION(S): Estradiol was administered subcutaneously for the first 4 weeks, followed by E2 plus P for 4 weeks, followed by a third 4-week washout period. MAIN OUTCOME MEASURE(S): Changes in plasma lipoprotein levels and oxidation of LDL and serum concentrations of E2 and P. RESULT(S): Levels of LDL cholesterol fell after 4 weeks of treatment with E2, compared with baseline. The lag time to half maximal light absorbancy after 4 weeks of E2 treatment was significantly increased compared with baseline. The maximal absorbance values and the slope of the propagation phase after 4 weeks of treatment with E2 were decreased compared with baseline. After 4 weeks of combined E2 and P treatment, all values were comparable to baseline. CONCLUSION(S): These results suggest that subcutaneous E2 therapy appears to enhance LDL resistance to oxidation and that this effect is attenuated by the addition of the P.
Authors: MaryFran Sowers; Daniel McConnell; Mary L Jannausch; John F Randolph; Robert Brook; Ellen B Gold; Sybil Crawford; Bill Lasley Journal: Clin Endocrinol (Oxf) Date: 2007-11-02 Impact factor: 3.478