sentence: The signal sequence – lacking FABP4 ( or Adipocyte-FABP or Adipokin-2 [ AP2 ] ) is secreted by adipocytes subjected to lipolytic agonists or nutrient deprivation , and the secreted form is proposed to control glucose production by hepatocytes and insulin secretion by pancreatic β - cells ( Cao et al ., 2013 ; Kralisch et al ., 2014 ; Wu et al ., 2014 ; Ertunc et al ., 2015 ; Hotamisligil and Bernlohr , 2015 ; Mita et al ., 2015 ) .