Serum cholesterol efflux potential in postmenopausal monkeys treated with tibolone or conjugated estrogens

Metabolism: Clinical and Experimental
Tomi S MikkolaRichard W St Clair

Abstract

Tibolone is a synthetic steroid used for the treatment of climacteric symptoms and the prevention of osteoporosis, but the effect on the cardiovascular system is unclear since tibolone lowers high-density lipoprotein (HDL) levels. We investigated if long-term treatment with tibolone or conventional hormone replacement therapy (HRT) in cynomolgus monkeys could affect their serum cholesterol efflux potential. Surgically postmenopausal cynomolgus monkeys were treated for 2 years with conjugated equine estrogens (CEE), CEE plus medroxyprogesterone acetate (MPA), low-dose tibolone, or high-dose tibolone. Plasma lipid, lipoprotein, and apolipoprotein levels were monitored during the study. The cholesterol efflux potential of the serum from each animal was determined in (3)H-cholesterol-labeled Fu5AH cells and skin fibroblasts in culture. Tibolone induced a dose-dependent 30% to 52% reduction in HDL levels. When HDL concentrations were reduced by 30%, as seen in women, there was no reduction in the serum cholesterol efflux potential in Fu5AH cells. With a 52% reduction in HDL, there was a 14% reduction in cholesterol efflux. Although CEE or CEE+MPA had no significant effect on HDL levels, CEE treatment increased serum cholesterol effl...Continue Reading

Citations

Nov 2, 2002·Stroke; a Journal of Cerebral Circulation·Thomas B ClarksonRichard W St Clair
Apr 12, 2006·Menopause : the Journal of the North American Menopause Society·Riina M TörmäläTomi S Mikkola
Sep 27, 2005·Climacteric : the Journal of the International Menopause Society
May 27, 2010·Gynecological Endocrinology : the Official Journal of the International Society of Gynecological Endocrinology·Cristina VassalleSilvia Maffei
Sep 29, 2011·Climacteric : the Journal of the International Menopause Society·H J Kloosterboer
Jan 18, 2006·European Heart Journal·Thomas B Clarkson
Feb 13, 2021·Cancers·Florent MorfoisseBarbara Garmy-Susini
Aug 2, 2003·Biochemical and Biophysical Research Communications·O SteinY Stein
Sep 11, 2004·Biochemical and Biophysical Research Communications·Ilaria ZanottiFranco Bernini

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