Fig. 4.

Activation of trypsin during the early phase of pancreatitis is independent of autophagy. a Multiple subcellular fractions were prepared after 1 h of caerulein-induced pancreatitis from pancreatic homogenate by differential Percoll centrifugation. Trypsinogen, α-amylase, trypsin and cathepsin B activity was measured using respective fluorogenic substrates. b Immunoblotting was performed in selected fractions for LC3 and ATG16 as markers for autophagosomes and Spink3 as well as syncollin as markers for secretory vesicles. Lamp1 indicates lysosomal compartment, Rab5 refer as marker for early and Rab9a for late endosomes. TGN38 is a marker for the trans-Golgi fraction and GRP78 markers the endoplasmic reticulum containing fractions. Data indicate that zymogen activity peaks in the heavier fractions representing the secretory compartment (lanes 5–13), while markers of autophagosomes were detected in the lighter fractions (lanes 34–36)