Regulation of cholesterol supply for mineralocorticoid biosynthesis.

In addition to intracellular cholesterol synthesis, plasma low- and high-density lipoproteins (LDL and HDL, respectively) are the major potential sources of a cholesterol precursor for steroid synthesis in all steroidogenic tissues. LDL- and HDL-cholesterol are taken up by cells through entirely distinct mechanisms. In the case of aldosterone production in the zona glomerulosa of the adrenal cortex, it has been assumed in the past that LDL is the major supplier of cholesterol. However, recent developments, in particular the discovery of the scavenger receptor class B type I for HDL and the characterization of its properties, have questioned this view. In fact, the nature of the challenging factor (angiotensin II or adrenocorticotropic hormone) appears to determine which pool of cholesterol is preferentially mobilized and which pathway (LDL receptor endocytosis or selective uptake through the HDL receptor) is regulated.