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Updated: Oct 26, 2026

Cholesterol Efflux Assay
Published on: March 6, 2012
Plasma membrane steroidogenic cholesterol: the relative importance of membrane internalization rate and cholesterol
D A Freeman1, A Romero, Y S Choi
1Division of Endocrinology, Metabolism, Hypertension, University of Oklahoma Health Sciences Center and VAMC, Oklahoma City 73104, USA.
Abstract:
Most cholesterol destined to become steroid hormone passes through the plasma membrane. Using MA-10 Leydig tumor cells as a model system, we determined that plasma membrane cholesterol disappeared 2.5-fold faster in cAMP-stimulated cells. Stimulation of MA-10 cells increased internalization so that 1.4-fold more membrane cycled through the cell per unit time. Increased internalization accounted for 26% of the cholesterol actually lost from cycling membrane. The remaining 74% was accounted for by increasing the extraction of cholesterol from internalized membrane.
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