To study adaptation of pancreatic amylase to diet, an affinity adsorbent, alpha-GHI-AH-Sepharose 4B, was used to determine amylase synthesis in cultured pancreatic acinar cells. This adsorbent exhibited a consistent binding capacity and was specific for amylase. Acinar cells from rats fed high fat (HF) or carbohydrate (HC) diets for 7 d were cultured 1-48 h in serum-free medium. Amylase activity remained significantly higher in HC cells than in HF cells through 24 h in culture, despite its decrease with time in culture. The relative synthesis of amylase (3H-phe amylase/3H-phe total protein x 100) was significantly higher in HC than in HF cells at isolation and remained higher during culture. These results demonstrate that this affinity adsorbent can be used to determine amylase synthesis and suggest that the effect of diet on amylase activity and relative synthesis persists in cultured pancreatic acinar cells.