Pancreatic acinar cells synthesize pancreatic lipase related protein 1 (PLRPl), which has a high degree of sequence and structural homology with pancreatic triglyceride lipase (PTL). PTL is required for efficient dietary triglyceride digestion, while the physiological role of PLRPl has not been elucidated, although some investigations have shown that its expression level is changed under some physiological or pathological conditions. Specific antigenic peptides were fused to glutathione S-transferase (GST) and purified recombinant fusion protein was used to generate polyclonal antisera by immunization of rabbits. The antisera could detect the antigen as low as 0.6 ng and PLRPI protein in 3 μg of mouse pancreatic juice extracts. The high specificity was verified in Western blot and immunohistochemistry analysis by using PLRPl knockout (KO) mice as the control. Furthermore, it was showed that food intake could increase the exocrine secretion of PLRPl into pancreatic juice. This implied that PLRPl may fulfill dietary digestion function in the digestion track.