Peroxisome proliferator activated receptor gamma (PPARy) is a protein that regulates the expression of genes through its heterodimerization with the retinoid x receptor (RXR) and subsequent modulation of expression of DNA (1). PPARy agonists e.g. rosiglitazone downregulate leptin gene expression (2)and upregulate adiponectin gene expression (3), thereby promoting more adipogenesis (4) and lipid accumulation.
Adiponectin, secreted by adipocytes, stimulates adipogenesis potently. It enhances adipocyte insulin sensitivity as well as glucose uptake. High levels are indicative of starvation (5). Too bad that dieting increases adiponectin, eh? Watch the weight pile back on as soon as food/insulin is there...
Talking of insulin, PPARy activation in pancreatic beta cells causes insulin hypersecretion, i.e. high insulin per unit glucose (6,7). This coupled with high adipose insulin sensitivity "PPARtitions" blood nutrition into adipocytes for storage. The insulin signalling in the adipocyte itself promotes PPARy activity through SREBP1c, thus producing a forward feedback loop of fattening.
This is thrift, why we exist today.
>>I'm really tired. Brush teeth, watch Louis CK comedy, sleep. Sounds cosy to me ;)
Bibliography
1. Wikipedia search PPAR and Youtube video search query adipogenesis
2. http://diabetes.diabetesjournals.org/content/47/4/507.full.pdf+html
3. http://www.nature.com/ijo/journal/v29/n1s/full/0802908a.html
4. http://www.jlr.org/content/46/7/1369.full.pdf
5. http://www.science20.com/news/how_adiponectin_sends_the_starvation_signal_to_the_brain
6. http://www.ncbi.nlm.nih.gov/pubmed/15561927
7. http://www.ncbi.nlm.nih.gov/pubmed/23372643
Short and informative. Adiponectin def. Contributues to wt regain as well as escalating obesity.
ReplyDeleteI hope that pun is better than Carbsane's pun.
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