The researchers found that in rodents, a molecule called 27-hydroxycholesterol, or 27HC, binds to the same receptors in the blood vessels of the heart to which estrogen binds....except to stop oestrogen from binding to those receptors. A woman with a chronically high level of LDL cholesterol will have much of the same effects on her as if she'd had oestrogen instead, they "appear" the same. Apart from on the vascular system, where the difference is marked.
In normal premenopausal women, the amount of 27HC generated from cholesterol is relatively low compared to the level of estrogen circulating in the blood, leading to enhanced cardiovascular protection. In contrast, when the level of 27HC is higher relative to estrogen, such as during the postmenopausal period or as a consequence of high cholesterol, the researchers speculate that 27HC out-competes estrogen to bind with estrogen receptors, blocking the function of the receptors and resulting in a loss of protection.
The researchers also found that 27HC works predominantly on estrogen receptors in the cardiovascular system. When it binds to estrogen receptors in other tissues, such as reproductive tissues, it has no effect on their reproduction-related functions. This property of 27HC makes it a “selective estrogen receptor modulator,” or SERM, the first such naturally occurring molecule known to exhibit such selectivity.
What the effect on genetic males is, I have no idea. My cholesterol levels, the dangerous LDL ones, were chronically abnormally high though. It was when they dropped precipitously (and I had a huge oestrogen spike) that Weird Stuff® happened.