Leptin 21 years later: From fat's big bang to central stage never before has adipose tissue been so active

Here we focus on Fat's Big Bang exploring officially by the discovery of leptin by Jeffrey Friedman and colleagues on 1 December 1994 in Nature. We recall their journey of discovery and discuss perspective on the further research in adipobiology and adipopharmacology of cardiometabolic, neuropsychiatric and cancer diseases. Friedman's seminal discovery makes a paradigm shift in our knowledge of adipose tissue biology-from merely a fat storage and metabolizer to a major endocrine and paracrine organ of the human body, producing more than 600 signaling proteins collectively termed adipokines. Leptin thus became the fundament in the obesity research and related diseases.