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Summary. The pancreaticoduodenal and portal venous blood flows were recorded electromagnetically in anaesthetized dogs. Blood glucose and IRI were measured in the arterial, portal, and peripheral venous as well as in the intestinal venous blood. By a mathematical model the actual net IRI output of the whole pancreas was estimated. Under basal conditions it is 10.2 + 2.4 mU/min (n = 30; 26 kg mean body wt.). After i.v. glucose injection, IRI output is rapidly enhanced. The biphasic nature of this reaction was unequivocally demonstrated by consideration of the ratio IRI output : blood glucose. Pancreaticoduodenal blood flow increases transiently in relation to the increased blood glucose concentration. The IRI secretion rate is well correlated with the blood glucose concentration and to the amounts of glucose or of blood reaching the whole pancreas. It is also correlated with the portal IRI concentration. The overall peripheral venous or arterial IRI concentrations are correlated with the IRI secretion rate, but not in all individual experiments. The different phases of IRI output (basal rate, stimulated output 1-10 min and 10-60 min) show no influence on each other, nor are they correlated with the peripheral IRI concentration area. Basal IRI output is negatively correlated with the glucose assimilation constants. These constants or the peripheral BG areas, however, are independent of the stimulated IRI output rate. However, both the assimilation constants and the peripheral BG areas are related to the peripheral IRI concentration areas. Hepatic uptake of insulin and dynamics of pancreatic blood flow seem to contribute considerably to the estimated correlation pattern.

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Isolated pancreatic rat islets incubated in vitro were used as a bioassay system for investigating the influence of human insulin antibodies on insulin secretion. Serum samples with different titres of insulin antibodies were obtained from juvenile diabetics after various periods of insulin therapy. The insulin secretion of isolated islets is enhanced by insulin antibodies and positively correlated to the measured antibody titres in serum.In agreement with Cahill (1973) and Block et al. (1973) we are of the opinion that the initial remission phase may play an important role in the prognosis of diabetes mellitus. This period is characterized by a recovered stabilization of diabetes due to an improved insulin secretion (Blaim 8c KielanowskaStunieka 1971;Menzel et al. 1972;Block et al. 1973). After different time periods the functional capacity of B-cells is exhausted and a more or less severe juvenile diabetes results. At present some possibilities for the final impairment of B-cell function are under discussion. Firstly it seems possible that the pathogenetic process continues to disturb the B-cells. Secondly the B-cell exhaustion could also be influenced by immunological reactions (cellu¬ lar and humoral) against exogenous insulin. Even if there is no strong cor¬ relation between the insulin-antibody titres and the termination of the initial remission phase, it is remarkable that under the commonly used insulin

After feeding intact conscious dogs 1000 g mashed meat, peripheral venous immunoreactive insulin activity (IRI) increases before any enhancement of amino nitrogen concentration. This course of IRI is paralleled by a decrease of free fatty acids. Meal feeding in dogs, whose pancreatic juice is completely diverted from the gut by a fistula, is followed by a similar IRI increase without a distinct enhancement of amino nitrogen. In oesophagus fistula dogs, sham-feeding meat in 9 out of 15 experiments results in a considerable early IRI increase which is correlated with a small but a significant decrease of blood glucose and free fatty acid concentrations. In these tests there was no amino nitrogen alteration either.