Insulin
Adipocytes are exquisitely sensitive to the effects of insulin. Binding of insulin to its receptor initiates the movement of glucose transporter GLUT4 to the plasma membrane to allow uptake of glucose by the adipocyte. Adipocyte GLUT4 trafficking not only keeps substrate available for DNL but also seems to mediate the cross-talk of adipose with liver and muscle to maintain systemic glucose homeostasis (Abel et al., 2001). GLUT4 trafficking is evident in equine adipocytes but there is a suggestion that more complex and additional insulin signalling pathways may also contribute (Warnken et al., 2017). Insulin also supresses lipolysis in equine and human adipocytes (Warnken et al., 2017; Duncan et al., 2007) and this acts to regulate the availability of free fatty acids and glycerol to the liver for gluconeogenesis.
Figure 1 Diagram showing some of the key functions of adipose tissue. Created with BioRender.com.