Адипонектин: адам ағзасындағы маңызды белок гормоны

Mammalian protein found in Homo sapiens

Adiponectin (also referred to as GBP 28, apM1, AdipoQ and Acrp30) is a protein hormone and adipokine, which is involved in regulating glucose levels and fatty acid breakdown. In humans, it is encoded by the ADIPOQ gene and is produced primarily in adipose tissue, but also in muscle and even in the brain.

Adiponectin is a 244 amino acid long polypeptide (protein). It has four distinct regions: The first is a short signal sequence that targets the hormone for secretion outside the cell; next is a short region that varies between species; the third is a 65 amino acid region with similarity to collagenous proteins; the last is a globular domain. Overall, this protein shows similarity to the complement 1Q factors (C1Q), but when the three dimensional structure of the globular region was determined, a striking similarity to TNFα was observed, despite unrelated protein sequences.

Adiponectin was first characterised in 1995 in differentiating 3T3 L1 adipocytes (Scherer PE et al.). In 1996 it was characterised in mice as the mRNA transcript most highly expressed in adipocytes. (precursors of fat cells) differentiating into adipocytes. The human homologue was identified as the most abundant transcript in adipose tissue. Contrary to expectations, despite being produced in adipose tissue, adiponectin was found to be decreased in obesity. Several single nucleotide polymorphisms in the coding region and surrounding sequence were identified from several different populations, with varying prevalences, degrees of association and strength of effect on type 2 diabetes. Berberine, an isoquinoline alkaloid, has been shown to increase adiponectin expression, which partly explains its beneficial effects on metabolic disturbances. Mice fed the omega 3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown increased plasma adiponectin. Curcumin, capsaicin, gingerol, and catechins have also been found to increase adiponectin expression. Phylogenetic distribution includes expression in birds and fish.

Lower levels of adiponectin are associated with ADHD in adults. Adiponectin levels were found to be increased in rheumatoid arthritis patients responding to DMARDs or TNF inhibitor therapy. A low adiponectin to leptin ratio has been found in patients with COVID 19 pneumonia compared to healthy controls. Exercise induced release of adiponectin increased hippocampal growth and led to antidepressive symptoms in mice.

Circulating levels of adiponectin can indirectly be increased through lifestyle modifications and certain medications such as statins. A small molecule adiponectin receptor AdipoR1 and AdipoR2 agonist, AdipoRon, has been reported. In 2016, the University of Tokyo announced it was launching an investigation into anonymously made claims of fabricated and falsified data on AdipoR1, AdipoR2, and AdipoRon. However, a systematic review concluded there is insufficient evidence to support the consumption of sweet potatoes to treat type 2 diabetes mellitus. Adiponectin is apparently able to cross the blood brain barrier. However, conflicting data on this issue exist. Adiponectin has a half life of 2.5 hours in humans.