In conscious trained dogs (Alsatians) the IRI-concentration in the peripheral venous blood after oral administration of glucose increases when the blood glucose is still unchanged. After one or two peaks during the first 20 min IRI increases parallel to the blood sugar increase. In relation to the intravenous injection of glucose the IRI maximum after oral administration occurs earlier. Furthermore the ratio of the IRI to blood sugar areas is raised. Without any blood sugar change the IRI concentration after oral application of tap water increases with one or two peaks. These peaks correspond to the first peaks after oral administration of glucose. These findings are discussed in the sense of a "feed-forward" of insulin secretion after feeding via N.vagus as well as via enterohormones. More attention should be payed to the IRI course during the early phase of the oral glucose tolerance test. Mdcanisme de la sdcrdtion d'insuline apr~s administration orale de glucose. I. Ddroutement multiphasique de la mobilisation de l'insuline apr~s administration orale de glucose ehez le chien dveiUg. JDiffdrences de comportement apr~s administration intraveineuse R~sumd. Chez des chiens-bergers 6veill6s et entraln6s, apr~s administration orale de glucose, la concentration d'IRI dans le sang veineux p6riph6rique augmente ddj~ alors que la glyc6mie n'a pas encore chang6. Apr~s un ou deux pies durant les ring4 premieres minutes, I'IRI augmente parall~lement au glucose sanguin. Comparativement h l'injeetion intra-veineuse de glucose, le maximum d'IRI, apr~s administration orale, se produit plus tSt. De plus, le quotient des surfaces d'IRI et de glyc6mie est 61ev6. Sans aucun changement du glucose sanguin, la concentration d'IRI augmente avec un ou deux pics aprSs administration orale d'eau potable. Ces pics correspondent aux deux premiers pics aprbs administration orale de glucose. Ces r6sultats sent discutds dans le sons d'une s6crdtion d'insuline pr6cddant la digestion via N.vague et via entdrohormones. I1 faut aceorder plus d'attention ~ l'6volution d'IRI durant la premiere phase du test de tol6rance au glucose par voie orale. Der Mechanismus der Insulinmobilisierung nach oraler Glucosegabe. I. Mehrphasigkeit der lnsulinmobilisierung nach oraler Glueosegabe beim wachen Hund und Differenzen zum Verhalten naeh intravenSser Glucoseinje]ction Zusammenfassung. Bei waehen trainierten Sch/~ferhunden steigt die Insulinkonzentration im peripheren Venenblut nach oraler Glucosegabe schon zu einem Zeitpunkt an, da die Glyk/imie noch nicht ver/indert ist. Nach Durchlaufer~ yon 1 oder 2 Gipfeln in den ersten 20 mill tritt der Anstieg ein, der parallel dem Blutzuckergipfel verl/~uft. Im Verh/~ltnis zur intraven6sen Glucosegabe liegt das erste IRI-Maximum nach oraler Verabf..olgung zeitlich friiher. Auch ist der Quotient aus IRI-Ubersehreitungsfl/iche und Blutzuckeriiberschreitungsfl/~che erh6ht. Ohne daI3 es zu einer Blutzuckerver/~nderung kommt, steigt auch nach oraler Gabe yon Leitungswasser die IRI-Konzentration 1-oder 2gipflig an. Diese Gi...

Forschung und Behandlung --Karlsburg und Garz, Bereich Klinik Karlsburg (Institutsdirektor und Leiter der Klinik : Prof. Dr. reed. habil. H. Bibergeil) und Bereich experimentelle Diabetesforscbung (damaliger Leiter : Doz. Dr. reed. habil. I-I. G. Lippmann) Eingegangen am 18. Dezember 1969 Effects of the intravenous infusion of nicotinic acid on blood concentrations of substrates, metabolites and hormones in juvenile-onset diabetesSummary. The effect of a 30 min infusion of nicotinic acid on the blood levels of glucose, pyruvate, lactate, FFA, glycerol, cateeholamines, and 1 l-OH-cortieosteroids was investigated over 180 rain in 73 insulin-dependent diabetics with different clinical states of metabolism and in 7 healthy subjects. The action of nicotinic acid on insulin secretion was measured in vivo in some diabetic and some healthy subjects by means of ILA. Studies on insulin secretion in vitro were done by measuring the insulin release from isolated islets of mouse pancreas. The insulin content of the incubation medium was estimated with the radio-immunological method. --It was shown that nicotinic acid in vitro stimulates insulin release from B cells significantly. In vivo the rise of serum ILA after nicotinic acid infusion was only deteetable in healthy subjeets and in diabetics of the stable type. Furthermore, a negative correlation was demonstrated between the peak of the FFA-rebound induced by nicotinic acid and the stimulatory effect of the drug on insulin secretion. The behaviour of blood glucose during infusion of nicotinic acid together with the daily insulin dosage permitted a metabolic distinction to be made between diabetics of the stable and unstable ('brittle') type.