lec 4: lipid metabolism Flashcards
fate of absorbed lipids
- uptake by tissue.
- utilization by tissue:
-oxidation
-conversion to glucose
-formation of tissue fat - storage (adipose tissue as triacylglycerols)
- secretion (sebaceous glands and lactating mammary glands).
synthesis of TAG
lipogenesis
destruction of stored fats to get energy
lipolysis
promotes glycolysis
insulin hormone
a hormone that stimulates glycogenesis (storage of glycogen)
insulin hormone
insulin restricts this process
glycogenolysis (breaking down of glycogen)
key enzyme of lipolysis
hormone sensitive lipase (HSL)
a process which is important for providing energy when fasting
lipolysis
synthesis of ketone bodies
ketogenesis
examples of ketone bodies
acetoacetate - acetone - β-hydroxubutyrate
only site of ketogenesis
liver
liver enzymes that help in ketogenesis
HMG-CoA synthase (synthesis) & HMG-CoA lyase (breaking down)
mainly derived from the oxidation of fatty acids
ketone bodies e.g. acetyl CoA
a process that happens only in the mitochondria of extra hepatic tissues
ketolysis
how does acetyl CoA help in the production of energy
by entering krebb’s cycle and as a result forming ATP
a condition characterized by the elevation of the level of ketone bodies in blood
ketosis (ketogenesis > ketolysis)
causes of ketosis
- severe diabetes mellitus
- prolonged fasting or starvation
- high fat and low carbs in diet
- prolonged administration of anti-insulin hormones especially in diabetic patients
an organ responsible for the synthesis of cholesterol present in blood
liver
key enzyme of cholesterol synthesis
HMG CoA reductase
a high level of cholesterol in blood
hypercholesterolemia (higher than 240 mg/dl)
causes of hypercholesterolemia
- dietary causes rich in fats, carbs and cholesterol.
- diabetes mellitus
- hypothyroidism
termed bad cholesterol
LDL
termed good cholesterol
HDL
important for reverse cholesterol transport
HDL
