Related Experiment Video
Updated: Aug 11, 2026

Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
Effects of estrogen and progesterone on plasma platelet-activating factor-acetylhydrolase activity and low-density
1Department of Obstetrics and Gynecology, Kumamoto University School of Medicine, Japan.
Objective:
We examined the effects of estrogen and progesterone on the plasma platelet-activating factor (PAF)-acetylhydrolase activity and lipoprotein concentrations in men.
Method:
Ten healthy men received 6 days of oral mestranol (0.24 mg/day) followed by 6 days of oral norethisterone (20 mg/day). The PAF-acetylhydrolase activity and lipoprotein profiles were determined in each subject prior to and following mestranol loading and following norethisterone administration.
Result:
The mestranol caused a significant decrease in both the plasma PAF-acetylhydrolase activity and the low-density lipoprotein (LDL) cholesterol concentrations of 26.4% and 26.9%, respectively; norethisterone appeared to revert the PAF-acetylhydrolase activity and LDL cholesterol concentrations to the levels observed prior to mestranol loading. In addition, the plasma PAF-acetylhydrolase activity was positive correlated with the LDL cholesterol concentration (r = 0.58, P < 0.001).
Conclusion:
The results of this study indicate that mestranol and norethisterone exert an effect on the plasma PAF-acetylhydrolase activity in men, possibly by influencing plasma LDL cholesterol concentrations.
More Related Videos
Related Concept Videos
Lipid-derived Compounds in the Human Body
Fat-soluble Vitamins
Fat-soluble vitamins, including vitamins A, D, E, and K, are required in minimal quantities, but their deficiencies can lead to severely abnormal physiological conditions. For example, vitamin A deficiency can cause night blindness, dry skin, delayed...
Target Cell Response to Hormones
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Cholesterol: Significance and Regulation
Considering cholesterol and...
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.
Menopause

