IMPACT OF PROTEIN-DEPRIVATION ON PROTEIN AND DNA-SYNTHESIS IN THE DEVELOPING RAT PANCREAS

The metabolic effects of protein malnutrition on growth and developmen t of the exocrine pancreas are largely unknown. The aim of the present study was to evaluate the effects of protein malnutrition on pancreat ic protein and DNA synthesis during postnatal development. Rat dams an d their offspring were fed a protein-deficient diet (6% casein) or a c ontrol diet (25% casein) during gestation, lactation and after weaning . Pancreatic protein and DNA synthesis were measured in vitro at postn atal ages 1, 3, 10, 23, 36 and 60 days, by assessing [H-3]leucine and [H-3]thymidine incorporation in freshly isolated acini, Different patt erns of protein synthesis were seen in the two groups. At birth, pancr eatic protein synthesis was low in both control and malnourished anima ls, At day 3, protein synthesis in the control acini increased 10-fold while synthesis in acini of the malnourished animal group was only 50 % of age-matched control values. No differences in protein synthesis w ere detected between the control and malnourished groups between 10 an d 36 days of age. At 60 days (adulthood), acinar protein synthesis dec lined in the control-fed rats, but a significant increase was observed in the malnourished animals (p < 0.0005). At birth, DNA synthesis was high in the acini from both control and malnourished animals. The low -protein diet induced a slight reduction in DNA synthesis at day 3, wi thout altering the general pattern during later stages of development. In conclusion, protein deprivation has variable effects on pancreatic protein and DNA synthesis at different stages of postnatal developmen t. Furthermore, the mechanisms of control within acini appear to be in trinsically regulated.