adiponectin presentation

ADIPONECTIN

Dr. HAFSA BASHIR

OBJECTIVES

Definition of Adiponectin Structure Secretion Functions Metabolic Regulation

INTRODUCTION A protein hormone produced and secreted exclusively by

Adipocytes (fat cells)

Adipocytes produce and secrete a number of proteins, including :

Leptin, Adipsin, Properdin, and Tumor necrosis factor (TNF).

An adipose tissue-specific factor was isolated and termed APM1 (AdiPose Most abundant gene transcript 1).

The protein product of APM1 is Adiponectin.

Adiponectin is a protein which in humans is encoded by the ADIPOQ gene. 

It is involved in regulating glucose levels as well as fatty acid breakdown.

ADIPOCYTES & ITS DERIVATIVES

DEFINITION OF ADIPONECTION

Adiponectin, also called Adipocyte complement related Protein is a 244 Amino acid Protein secreted from Adipose Tissue.

STRUCTURE OF ADIPONECTIN: Adiponectin is a 244-amino-acid-long

polypeptide.

There are Four distinct regions of adiponectin:

1. The first is a short signal sequence that targets the hormone for secretion outside the cell.

2. Short region that varies between species3. The third is a 65-amino acid region with

similarity to collagenous proteins4. The last is a globular domain. 

STRUCTURE:

SECRETION Adiponectin is exclusively secreted from:  Adipose tissue   Placenta in pregnancy Into the bloodstream.  Adiponectin accounts for approximately 0.01%

of all plasma protein at around 5-10 μg/ml. Plasma concentrations: Females having Higher levels than Males. Females 16.6 + 5 mg/ml Males 7.9 + 0.5 mg/ml

RECEPTORS

Adiponectin binds to a number of receptors:

1. Adiponectin receptor 1 – ADIPOR12. Adiponectin receptor 2 – ADIPOR23. T-cadherin - CDH13

PHYSIOLOGIC FUNCTIONS OF ADIPONECTIN ADIPOR1/R2

FUNCTIONS OF ADIPONECTINAdiponectin modulates a number of metabolic processes including:

ADIPONECTIN EFFECTS Glucose flux

Decreased gluconeogenesis Increased glucose uptake

Lipid catabolism Triglyceride clearance

Protection from endothelial dysfunction  Insulin sensitivity Weight loss Control of energy metabolism. Reduction of TNF-alpha

METABOLIC REGULATION Obesity is associated with decreased

Adiponectin.

 Levels of adiponectin are reduced in Diabetics compared to Non-Diabetics.

Weight reduction significantly increases circulating levels.

Adiponectin levels were found to be increased in rheumatoid arthritis patients responding to TNF inhibitor therapy.

The hormone plays a role in the suppression of the Metabolic derangements that result in:

 Type 2 diabetes   Obesity  Atherosclerosis Non-Alcoholic Fatty Liver Disease (NAFLD)

A low level of adiponectin is an independent risk factor for developing:

Metabolic syndrome Diabetes mellitus

 RELATIONSHIP B/W SERUM ADIPONECTIN, LEPTIN, RESISTIN AND VISFATIN LEVELS IN

DM AND CONTROL SUBJECT

INCREASES THE LEVEL OF ADIPONECTIN

Circulating levels of adiponectin can indirectly be increased through

lifestyle modifications & certain drugs such as statins.

A small molecule adiponectin receptor (ADIPOR1 and ADIPOR2) agonist (AdipoRon) has been reported.

Extracts of sweet potatoes have been reported to increase levels of adiponectin and thereby improve glycemic control in humans

REFERENCES  "cDNA cloning and expression of a novel

adipose specific collagen-like factor, apM1 (AdiPose Most abundant Gene transcript 1)". Biochem. Biophys.

"The role of the novel adipocyte-derived hormone adiponectin in human disease".

The role of the adipocyte hormone adiponectin in cardiovascular disease". Curr Opin Pharmacol