GlucagonPancreatic HormonesPancreatic PolypeptidePancreasGlucagon-Like PeptidesSplanchnic NervesProglucagonGastrointestinal HormonesSecretory RateInsulinBlood GlucoseRadioimmunoassayReceptors, GlucagonDogsIslets of LangerhansGlucoseArginineGlucagon-Secreting CellsLiverSomatostatinHypoglycemiaGluconeogenesisGlucagon-Like Peptide 1EpinephrineRats, Inbred Strains