Related Experiment Video
Updated: Aug 5, 2026

Ovariectomy and 17β-estradiol Replacement in Rats and Mice: A Visual Demonstration
Published on: June 7, 2012
A continuous estrogen-progestogen regimen for climacteric complaints. Effects on lipid and lipoprotein metabolism
Abstract:
The lipid composition of serum and the lipoprotein fractions, very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) were determined in 26 peri- and postmenopausal women treated with a daily dose of 2 mg 17-beta-estradiol, 1 mg estriol and 1 mg norethisteroneacetate in a continuous regimen for 12 months. A decrease was noted in all serum lipids, triglycerides, cholesterol and phospholipids during treatment. When comparing the lipid values after 3 and 12 months of treatment a tendency was found to approach pretreatment values with time. A reduction of triglycerides in VLDL after 3 months, concomitant with a decrease in HDL-cholesterol, was interpreted as an effect mainly of the progestogen component. A decrease of free cholesterol in LDL was found during treatment. The ratio of LDL-cholesterol/HDL-cholesterol was unaltered when comparing values before vs. after 3 and 12 months of treatment. Decreased levels of HDL-cholesterol and elevated levels of LDL-cholesterol are considered to be risk factors for coronary heart disease. The significance of lipid metabolic effects induced by treatment in the present study on a longterm basis is hard to evaluate in terms of atherogenicity.
More Related Videos
Related Concept Videos
Hormonal Regulation
Lipid-Lowering Drugs: Statins and Miscellaneous Agents
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Menopause
Oral Drug Delivery Systems: Continuous-Release Systems

