The aim of the present study was to determine the effect of thiamin deficiency on pancreatic acinar cell function. Weight-matched triplets of Sprague-Dawley rats were fed a purified thiamin-deficient diet ad libitum, isocaloric amount of purified thiamin-sufficient diet or rat feed ad libitum for a mean of 33 (+/- 0.5 SEM) days. Effect of diets on body weight, pancreas weight, DNA, RNA, protein and amylase content, synthesis of protein and secretion were determined. Controls diet effect was considered when fed ad libitum controls were different from isocaloric controls. Thiamin effect was considered when thiamin-deficient diet treatment resulted in effects similar to control diet effects in addition to specific effects that included reduced body weight, total protein, and amylase. Basal and bethanechol (10-4 M) stimulated secretion of protein and amylase were increased. It is concluded from this study that thiamin deficiency per se induced a reduction in body weight, pancreatic protein and digestive enzyme content and increased protein and digestive enzyme secretion due to metabolic derangements leading probably to altered redox state of pancreatic acinar cell.