The determination of whether metabolic homogeneity exists in an organ is of importance to both the clinician and investigator. These studies examine synthesis of DNA, RNA, protein, and oxygen uptake in the three anatomical segments of the rat pancreas. There was rather close agreement among the three segments insofar as these metabolic measurements were concerned. We concluded that there is metabolic uniformity in the rat pancreas and that measurements obtained in one segment reflect activities in the other two segments.