Lipolysis- 17

When the body is at a fasted state, glucose levels drop and insulin decreases while glucagon rises. As a result, the body switches its main fuel source from glucose to ___________ for energy production.

fatty acids

What part of the body is the major site of fatty acid utilization in a fasted state?

(spares gylcogen stores)

skeletal muscle

What is the predominant provider of fatty acids?

adipose tissue

After the adipose tissue what are 2 other minor contributors of fatty acids?

VLDLs and Intracellular TAG stores

Describe the lipolyisis process.

breakdown of TAGs into 3 fatty acids and one glycerol

can adipose tissue re-use glycerol to make a triglyceride and why?

no, becuase adipose tissue lacks enzyme, glycerol kinase

What organ picks up the glycerol being used to make new glucose within lipolysis?

liver

where do we make all glycerol back bones?

adipose tissue de novo(from scratch)

Explain when we favor lipolysis?

in a fasted state; after 20min of low to moderate exercise and post-exercise

Lipolysis is a tightly regulare process in both ___________ and _________.

adipocytes and skeletal miscle

Name the 3 main enzymes and 2 main regulatory proteins within lipoysis.

enzymes: adipose triacylglycerol lipase(ATGL), hormone sensitve lipase(HSL), and monoacylglycerol lipase

regulatory proteins: Perilipin and CG-I58

What is lipolysis activated by and inhibited by?

activated by catecholamines: epinephrine and noepinephrine 

inhibited by: insulin

Desrcibe how the non-stimulated(basal) state and stimulated state work within lipolysis?

non-stimulated(basal): slightly active to provide mininum of fatty acids needed; NOT due to hormones

stimulated state(fasted and excercise): due to hormones; increase amount of fatty acids released

When perilipin is phosphorylated, it releases _________, and can now associate with ______ and make a greater rate of liploysis.

CGI-58; ATGL

ATGL hydrolyzes _______ and HSL hydrolyzes ________.

triacylglycerides; diacylglycerides

What does insulin do to lipolysis?

it dephosphorylates and turns off lipolysis 

true or false: lipolysis stays on in a fasted and prolonged fasted state

explain yes or no.

true, becuase we can never get rid of fatty acids

Different quanites of a-cells and b-cells is going to drive how active ________ tissue. 

adipose 

true or false: genetics can play a role in how active your adipose tissue is

true

insulin binding to this receptor, activates the enzyme: __________

phosphodiesterase

what is the product of lipolysis?

fatty acids

what is the one enzyme that is regulated allosterically by Fatty Acyl-CoA?

Hormone sensitive lipase 

What are the products of lipolysis?

free fatty acids and glycerol 

What are the 2 ways insulin turns of lipolysis.

via phophodiesterase(gets rid of CAMP then PKA) and protein phosphatase II(dephosphorylates lipolysis enzyme)

what are the products of lipolysis?

3 free fatty acids and glycerol backbone

does the liver or the muscle express glycerol kinase within lipolysis?

muscle

what 2 fatty acid transporters would be present on the skeletal muscle surface?

fatty acid binding protein and fatty acid transport protein 

FAT/CD36 is going to be housed intracellulary unitl stimulated by _________.

insulin

what is the enzyme that adds to the CoA?

how many atp equivalent does it use?

Acyl-CoA synthetase(ACS); 2 ATP equivalent

where does B-oxidation occur?

this process includes fatty acids being oxidized _____ carbons at a tiem to produce acetyl-coA

mitochondrial matrix; 2 carbons

fatty-Acyl CoA is within the _________.

cytoplasm

what shuttle transports the fatty-acid into the mitochondria?

carnitine shuttle

B-oxidation is a series of ____ reactions that are repeated until fatty acid is completely oxidized.

4 reactions

what 2 things are produced within each cycle of B-oxidation?

Every cycle we make an acetyl-coA we make ____ ATP.

FADH2 and NADH; 4 ATP

how many ATP are made per acetyl-coA in TCA cycle?

4 ATP

What are the 4 enzymes of B-oxidation?

Acyl-CoA-dehydrogenase, B-hyrdoacyl-CoA dehydrogenase, thiolase, and Enoyl-CoA dehydratase

Within B-oxidation, Acyl-CoA dehydrogenase produces _________.

FADH2

Within B-oxidation, B-hydroxyacyl-CoA dehydrogenase produces _________.

NADH

we regulate B-oxidation with __________ entry into the mitochondria at ______.

fatty acid; CPT1

__________ is a potent inhibitor of CPT1, which prevents entry of fatty acids into the matrix of the mitochondria.

Malonyl-CoA

What is the enzyme that makes malonyl-CoA?

Acetyl-CoA carboxylase(ACC)

what are the 2 isoforms of Acetyl-CoA carboxylase(ACC) and were is most prominent in?

ACC1= liver and adipose tissue

ACC2=skeletal muscle

In a fed state, ACC(acetyl-CoA carboxylase) is ON, making ________, which blocks CP2-1 entry, and turns off _______.

malonyl-CoA; B-oxidation 

In a fasted state, what enzyme removes malonyl-CoA. It converts malonyl-CoA back into acetyl-CoA?

Malonyl-CoA decarboxylase(MCD)

What is malonyl-CoA regulated by?

AMPK

When we phosphorylate ACC(acetyl-CoA carboxylase) we turn it _____(off/on), when we phosphorylate MCD(malonyl-CoA decarboxylase) we turn it ______(off/on).

Off; On