Dietary cholesterol is transpoed from intestine to liver by:
**Core Concept**
Cholesterol absorption from the intestine into the bloodstream involves a complex process, primarily facilitated by the intestinal enzyme cholesterol ester transfer protein (CETP) and the liver enzyme low-density lipoprotein receptor (LDLR). The transport of dietary cholesterol from the intestine to the liver plays a crucial role in maintaining cholesterol balance and lipid homeostasis.
**Why the Correct Answer is Right**
Dietary cholesterol is transported from the intestine to the liver via the lymphatic system and the bloodstream, specifically through high-density lipoproteins (HDL). HDL particles, also known as "good cholesterol," facilitate the reverse cholesterol transport pathway, where excess cholesterol is removed from peripheral tissues and transported to the liver for excretion. This process is mediated by the enzyme CETP, which exchanges cholesterol esters in HDL for triglycerides in very-low-density lipoproteins (VLDL).
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because HDL is involved in the reverse cholesterol transport pathway, not the direct transport of dietary cholesterol from the intestine to the liver.
* **Option B:** This option is incorrect because LDL receptors are primarily involved in the clearance of LDL cholesterol from the bloodstream, not the transport of dietary cholesterol from the intestine to the liver.
* **Option C:** This option is incorrect because VLDL is involved in the transport of endogenous triglycerides and cholesterol from the liver to peripheral tissues, not the transport of dietary cholesterol from the intestine to the liver.
**Clinical Pearl / High-Yield Fact**
The liver plays a crucial role in maintaining cholesterol balance by regulating the expression of LDL receptors, which in turn affects the levels of LDL cholesterol in the bloodstream.
**Correct Answer:** D. HDL.