There are 5 classes of steroid hormones: testosterone (androgen), estradiol (estrogen), progesterone (progestin), cortisol/corticosterone (glucocorticoids), and aldosterone (mineralocorticoid). Testosterone and its most potent metabolite, dihydrotestosterone (DHT), progesterone, and estradiol are classified as sexual steroids, while cortisol/corticosterone and aldosterone are collectively referred to as corticosteroids.
Sexual steroids are essential for the body’s development and proper functioning. They regulate sexual differentiation, the emergence of secondary sexual characteristics, sexual behavior patterns, and reproduction. The production of these steroids follows sexual dimorphism, involving differences not only in hormonal action but also in regulation and temporal patterns of production. However, they all depend on a strategic chemical substance: cholesterol.
Since cholesterol cannot be dissolved in the blood, it is “carried” through the body using a “transportation medium” called lipoprotein – which is essentially cholesterol with a protein coating. In humans, we find two types of lipoproteins doing this job: low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
All steroid hormones are produced using cholesterol from a common precursor (pregnenolone) formed by the enzymatic cleavage of a 6-carbon side chain from the 27-carbon cholesterol molecule. This reaction is catalyzed by the cytochrome P450 cleavage enzyme (P450scc, CYP11A1) at the mitochondrial level.
Tissues that produce steroid hormones capture cholesterol from 4 main sources: (1) Cholesterol synthesized by the body from acetate; (2) Cholesterol harvested from HDL and LDL; (3) Cholesterol derived from the hydrolysis of cholesterol ester deposits; and (4) Cholesterol internalized by the plasma membrane.
Although the 3 main steroid-producing organs (adrenal, testicles, and ovaries) can produce cholesterol under the influence of certain hormones, the adrenals and ovaries preferentially use cholesterol captured directly from the bloodstream.
Foods, drugs, and toxins that interfere with mitochondrial function or the body’s ability to maintain good cholesterol reserves (or sustain healthy circulating cholesterol levels) will ultimately undermine your sexual hormone levels – especially testosterone.
This leads me to question to what extent the “war on cholesterol” is not just a disguise for the many faces of the notorious “war on masculinity” that has fiercely plagued the West for the past 5 decades.
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