Final answer:
Intracellular unesterified or free cholesterol can increase through inhibition of HMG-CoA reductase, elevation of plasma free fatty acids, and failure in cholesterol biosynthesis regulation.
Step-by-step explanation:
Intracellular unesterified or free cholesterol can increase through several processes:
- Inhibition of HMG-CoA reductase - Excess cholesterol and its intermediate mevalonate can inhibit the enzyme HMG-CoA reductase, which is involved in cholesterol synthesis.
- Elevation of plasma free fatty acids - Increased levels of free fatty acids can lead to increased secretion of very low-density lipoproteins (VLDL) by the liver, resulting in higher cholesterol output into the circulation.
- Failure in cholesterol biosynthesis regulation - When the regulation of cholesterol biosynthesis is impaired, it can contribute to the formation of cholesterol-rich deposits in arteries and arterioles.