NPP1 helps scavenge extracellular nucleotides in order to meet the high purine and pyrimidine requirements of dividing cells. In T-cells, it may scavenge NAD from nearby dead cells as a source of adenosine.
The pyrophosphate produced by NPP1 in bone cells is thought to serve as both a phosphate source for calcium phosphate deposition and as an inhibitory modulator of calcification. NPP1 appears to be important for maintaining pyrophosphate/phosphate balance. Overactivity of the enzyme is associated with chondrocalcinosis, while deficiency correlates to pathological calcification.
NPP1 inhibits the insulin receptor in vitro. In 2005, overexpression of the isoform was implicated in insulin resistance in mice. It has been linked to insulin resistance and Type 2 diabetes in humans.