13.03.1 Cholesterol

Cholesterol is good for you! That is, provided it is at normal levels, where it is used in membrane synthesis, steroid hormone synthesis and the synthesis of bile acid (Figure 13.12).  It is only excessive cholesterol that leads to atherosclerosis.  

Figure 13.12 Roles of cholesterol (Copyright QUT, Sheila Doggrell)

Dietary fat is broken down successively to chylomicrons, chylomicron remnants, very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density lipoproteins (LDL), triglycerides and high density lipoprotein (HDL).  VLDL and IDL are carriers of triglycerides and LDL and HDL are carriers of cholesterol (also known as LDL-cholesterol etc).  LDL-cholesterol is the major reservoir of cholesterol in human plasma (60-70% of total cholesterol).

If you decrease the level of LDL cholesterol “the bad cholesterol”, there is a decreased risk of atherosclerosis, and its consequences.  Conversely, if you increase the HDL cholesterol “the good cholesterol”, there is a substantial decreased risk of atherosclerosis. 

High LDL cholesterol is considered to be 4.94 mmol/L or above, and low HDL cholesterol is 0.75 mmol/L or lower.  Drug treatment is available to decrease LDL cholesterol and increase HLD cholesterol.

Pharmacology InOneSemester,
Mar 24, 2015, 9:57 PM