Effects of early protein restriction and adult obesity on rat pancreatic hormone content and glucose tolerance

Rats were fed a diet containing either 20% ("control") or 8% ("reduced-prot ein") protein throughout pregnancy and lactation. Their female offspring we re weaned onto the same respective diets. At 63 days of age one set of cont rol and reduced-protein rats (n = 16 per group) underwent intraperitoneal g lucose tolerance tests and one week later were killed and their pancreatic hormones extracted and measured. The reduced protein rats had better glucos e tolerance (p < 0.001) and lower pancreatic insulin (p < 0.01) and amylin (p < 0.01) contents. Further sets of control and reduced-protein rats were then fed either chow or a cafeteria-style diet (n = 16 in each of the four groups). These rats underwent intraperitoneal glucose tolerance tests at 13 3 days of age, which showed the cafeteria-fed animals to have a worse gluco se tolerance than the chow-fed animals irrespective of previous diet exposu re (p < 0.0001). One week later reduced-protein rats still had lower pancre atic insulin contents (p < 0.05) (and a trend for lower amylin contents), b ut also had increased pancreatic glucagon contents (p < 0.05), There were n o detectable differences in pancreatic somatostatin-like immunoreactivity o r pancreatic polypeptide contents. These results are consistent with pancre atic beta- and alpha-cells being selectively susceptible to effects associa ted with early dietary protein restriction.