What female hormone produced by the ovaries may protect against heart disease in premenopausal women?

Estrogen, a female hormone produced by the ovaries, plays a significant role in protecting against heart disease in premenopausal women. This protection is primarily due to estrogen's effect on lipid metabolism and its ability to maintain healthy blood vessels. Estrogen helps to regulate cholesterol levels by increasing high-density lipoprotein (HDL), which is often referred to as "good" cholesterol. It also has a vasodilatory effect, which means it helps blood vessels relax and improve blood flow.

Additionally, estrogen contributes to maintaining the integrity of the endothelium, the inner lining of blood vessels, thus reducing the risk of atherosclerosis—the buildup of plaques in the arteries that can lead to heart disease. These cardiovascular protective benefits are particularly notable in premenopausal women, as estrogen levels decrease significantly after menopause, which is associated with an increased risk of heart disease.

The other hormones listed do not have the same protective effects on heart health in the context described. For example, progesterone is primarily involved in the regulation of the menstrual cycle and pregnancy; testosterone is mainly known for its role in male characteristics and reproductive functions, and while it has some influence on female health, it is not primarily tied to cardiovascular protection in women; oxytocin