Pancreatic Hormones and Plasma Glucose: Regulation Mechanisms in the Goose under Physiological Conditions - IV-Effects of Food Ingestion and Fasting on Pancreatic Hormones and Gut GLI

Previous experiments using physiological variations of plasma glucose or pancreatic hormones showed the existence of glucose-pancreatic hormone feed-back mechanisms in the fasted Goose. The present studies investigated this regulation in the fed state. In normal and depancreatectomized fed, or force-fed geese, plasma glucose (G), plasma immunoreactive insulin (IRI) and total plasma glucagon-like-immunoreactivity (GLI) (using a non-specific antiserum L 7/69) were measured. Plasma pancreatic glucagon (GG) and gut GLI were assessed either with a pancreas-specific antiserum (30K) or by comparison between normal and pancreatectomized animals. Normal force-fed geese are hyperglycemic and hyperinsulinemic; plasma GLI first declines and then rises slightly above the basal level; normally fed animals show no significant variation in palsma GLI. These observations can be attributed to opposed variations in plasma pancreatic and gut GLI's: a) plasma pancreatic glucagon (measured with 30K) decreases by 50% after feeding b) plasma gut GLI increases in pancreatectomized geese after force-feeding or oral glucose. In conclusion 1 - the glucose-glucagon and the glucose-insulin feed-back mechanisms operate in the fed state. 2 - feeding increases gut GLI secretion.