Differential effects of subcutaneous estrogen and progesterone on low-density lipoprotein size and susceptibility to oxidation in postmenopausal rhesus monkeys

• Published in: Fertility and sterility Vol. 68; no. 3; pp. 525 - 530
• Main Authors: McKinney, Karen A., Duell, P.Barton, Wheaton, David L., Hess, David L., Patton, Phillip E., Spies, Harold G., Burry, Kenneth A.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.09.1997; Elsevier Science
• Subjects: Animals; Biological and medical sciences; Estradiol - administration & dosage; Estradiol - pharmacology; estrogen; Female; Hormones. Endocrine system; LDL oxidation; Lipoproteins, LDL - metabolism; Longitudinal Studies; Macaca mulatta; Medical sciences; menopause; Pharmacology. Drug treatments; Postmenopause - metabolism; progesterone; Progesterone - administration & dosage; Progesterone - pharmacology; Prospective Studies; rhesus monkeys; estrogen; menopause; rhesus monkeys; LDL oxidation; progesterone; Drug combination; Replacement therapy; Menopause; Estrogen; Monkey; Macaca mulatta; Ovarian hormone; Lipoprotein LDL; Vertebrata; Mammalia; Animal; Primates; Simioidea; Postmenopause; Subcutaneous administration; Oxidation; Progesterone; Sex steroid hormone
• ISSN: 0015-0282; 1556-5653
• DOI: 10.1016/S0015-0282(97)00237-9

Objective: To study the differential effects of subcutaneous E 2 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 E 2 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 E 2 and P. Result(s): Levels of LDL cholesterol fell after 4 weeks of treatment with E 2, compared with baseline. The lag time to half maximal light absorbancy after 4 weeks of E 2 treatment was significantly increased compared with baseline. The maximal absorbance values and the slope of the propagation phase after 4 weeks of treatment with E 2 were decreased compared with baseline. After 4 weeks of combined E 2 and P treatment, all values were comparable to baseline. Conclusion(s): These results suggest that subcutaneous E 2 therapy appears to enhance LDL resistance to oxidation and that this effect is attenuated by the addition of the P.