Previous studies have shown a variety of immunological abnormalities in Type 1 (insulin-dependent) diabetes, including disturbances in peripheral lymphocytes and anti-lymphocyte antibodies. We measured subsets of T and natural killer cells with monoclonal antibodies in patients with diabetes, and also assayed for anti-lymphocyte antibodies using dual colour immunofluorescence and flow cytometry. We found a significant decrease in numbers of Leu 3a (helper/inducer) cells in Type 1 diabetic patients of recent onset and intermediate levels in patients with longer duration of the disease. Leu 4 (pan T cell) levels were reduced in Type 1 diabetic patients of more than 4 months duration. Leu 7 (natural killer cells) were increased in Type 2 (non-insulin-dependent) diabetic patients. Individual Type 1 diabetic patients of recent onset showed low levels of Leu 7 and 11 a (natural killer cell) levels with normal 3a levels. Autoantibodies against Leu 3a + cells were present in higher titres in the Type 1 diabetic patients of recent onset than in control subjects. We conclude: (1) Leu 3a cells may be decreased in Type 1 diabetic patients of recent onset and return to normal with time; (2) low numbers of Leu 7 and 11a cells with normal numbers of Leu 3a may be seen in some Type 1 diabetic patients of recent onset, which may help explain previous reports of decreased suppressor cells; (3) Leu 7 levels may be increased in Type 2 diabetes; (4) autoantibodies against Leu 3a + peripheral lymphocytes may be seen in Type 1 diabetic patients of recent onset. These appear to be a marker of autoimmune phenomena rather than immunological mediators.

A B S T R A C T The pathogenesis of hyperglucagonemia and of the alterations in the pattern of circulating immunoreactive glucagon (IRG) associated with renal insufficiency was studied in rats in which a comparable degree of uremia was induced by three different methods, i.e., bilateral nephrectomy, bilateral ureteral ligation, and urine autoinfusion. Nephrectomized and ureteral-ligated rats were markedly hyperglucagonemic (575+95 pg/ml and 492+54 pg0ml, respectively), while IRG levels of urine autoinfused animals (208±35 pg/ml) were similar to those of control rats (180±26 pg/ml), indicating that uremia per se does not account for the hyperglucagonemia observed in renal failure. Similarly, plasma IRG composition in this group of animals was indistinguishable from that of controls, in which 88.2±5.9%o of total IRG consisted of the 3,500-mol wt fraction. The same component was almost entirely responsible (82.6±4.1%) for the hyperglucagonemia observed in ligated rats, while it accounted for only 57.6±5.0%o of the circulating IRG in nephrectomized animals. In the latter group, 36.8±6.6% of total IRG had a mol wt of approximately 9,000, consistent with a glucagon precursor. This peak was present in samples obtained as early as 2 h after renal ablation and its concentration continued to increase with time reaching maximal levels at 24 h.These results confirm that the kidney is a major site of glucagon metabolism and provide evidence that the renal handling of the various circulating IRG This study was presented in part at

A B S T R A C T Total plasma immunoreactive pancreatic glucagon (IRG) was measured in samples taken simultaneously from the proximal portal vein and superior vena cava of 26 healthy rats. The portalperipheral ratio of IRG was 2.80±0.25, the portalperipheral difference (A) 124±15 pg/ml, and percentage extraction 58±+3. Gel filtration of paired portal and peripheral vein samples showed that reduction in the 3,500-dalton IRG component (glucagon) in peripheral samples accounted for almost all the differences, there being minimal and inconsistent changes in the high molecular weight (>40,000) fraction. The portalperipheral ratio of the 3,500-dalton glucagon was 5.24±+1.10, the portal-peripheral difference 130+33 pg/ml, and the percentage extraction 81±5.To study the transhepatic differences in the 9,000-dalton "proglucagon-like" material, the experiment was repeated in nine rats 24 h after bilateral nephrectomy, a procedure which increases plasma levels of this fraction. The portal-peripheral ratio for plasma IRG in these rats was 1.48+0.12, the portal-peripheral difference 140±29 pg/ml, and percentage extraction 28+5. Gel filtration revealed no consistent differences between portal and peripheral concentrations of the 9,000-and >40,000-dalton components, which comprised 40 and 13%, respectively, of the mean IRG level of 492+35 pg/ml. In contrast, there were marked differences between portal and peripheral levels of the 3,500-dalton component, the ratio being 3.42 +0.63, the portal-peripheral difference 182+32 pg/ml, and percentage extraction 64±5. Similar studies in a healthy dog, in which species there are significant circulating levels of the 9,000-dalton IRG component, confirmed the selective hepatic extraction of the 3,500-dalton fraction. We conclude that the various IRG fractions are metabolized differently by the liver, and that portalperipheral ratios based on direct assay of plasma IRG will vary depending on the percentage glucagon immunoreactivity in each fraction; the greater the combined contribution of fractions other than the 3,500-dalton component to total plasma IRG, the lower will be the ratio. Because of the heterogeneity of circulating IRG and significant differences in the metabolism of its various components, gel filtration of plasma samples is necessary for precise quantitation of the hepatic uptake of each particular fraction.

A B S T R A C T The renal handling of' the biologically active glucagon component (the 3,500-mol wt fraction of immunoreactive glucagon [IRG]) and the contribution of the kidney to its overall peripheral metabolism were studied in normal and uremic rats. The metabolic clearance rate of glucagon was 31.8 ± 1.2 ml/min per kg in normal animals and was diminished by approximately one-third in each of three groups of rats with compromized renal ftinction:22.3+1.6 ml/min per kg in partially (70%) nephrectomized; 22.9±3.3 ml/min per kg in bilaterally ureteral ligated; and 23.2± 1.2 ml/min per kg in bilaterally nephrectomized animals. In normal rats the kidney contributed 30% to the overall metabolic clearance of the hormone and the renal extraction of endogenous and exogenous glucagon was similar, averaging 22.9±1.6% and was independent of plasma IRG levels over a wide range of arterial concentrations. The remnant kidney of partially (70%) nephrectomized aniimals continued to extract substantial amounts (16.6±4.2%) of the hormone, but accounted for only 8% of the total peripheral catabolism of' IRG. In the two groups of' animals with filtering kidneys, renal glucagon uptake was linearly related to its filtered load and could be accounted for by glomerular filtration and tubuilar reabsorption. However, the kidneys of animals with both ureters ligated (renal extraction of' inulin = 3.2±1.8%) and hence virtual absence of glomiiertilar filtration, continuied to extract 11.5±1.9% of the renal arterial glucagon, contributing by 9% to its overall metabolic clearanee, indicating that IRG uptake occurs also from the post glomerular capillaries.