The effects of epidermal growth factor (EGF), insulin, and insulin-like growth factor I (IGF-I) were examined alone and in combination on rat pancreatic acinar cells cultured 48 h in serum free medium. IGF-I at a concentration of 2.7 nM maintained viability of cultured acinar cells comparably to EGF. In contrast, insulin was less effective in maintaining acinar viability, even at high concentrations (170nM). There were no additive or interactive effects of these growth factors on acinar viability. EGF significantly increased [3H]-phenylalanine incorporation into acinar protein and the specific activity of phenylalanine-acylated transfer RNA (tRNAphe), but did not change the apparent rate of protein synthesis when compared with insulin of IGF-I. EGF with insulin, IGF-I, or both resulted in significantly lower specific activities of tRNAphe when compared to EGF alone, but all had comparable rates of total phe-incorporation. Acinar cells readily degraded insulin, but not EGF or IGF-I. These results demonstrate some specificity in the acinar requirement for growth factors (EGF = IGF-I greater than insulin) in maintaining viability in culture.