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StAR

Meaning

StAR is the acronym for Steroidogenic Acute Regulatory protein, a vital transport protein that mediates the rate-limiting step in the biosynthesis of all steroid hormones, including cortisol, aldosterone, testosterone, and estrogen. Its primary function is to facilitate the rapid transfer of cholesterol, the universal precursor molecule, from the outer mitochondrial membrane to the inner mitochondrial membrane within steroid-producing cells. StAR activity is the key point of acute regulation for the entire steroidogenesis pathway.