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In order to evaluate the value of diabetic Japanese monkeys (Macaca fuscatus) as an animal model for studying the pathogenesis of diabetic neuropathy, morphological examinations were performed on myelinated nerve fibers and endoneurial microvessels at three levels of the lower limb nerve in eight streptozocin (STZ)-diabetic monkeys with the duration of diabetes up to 36 months and in four roughly age-matched control monkeys using a computer-assisted image analyzer. Nerve fiber loss was not found, although a tendency for nerve fiber atrophy was found in diabetic monkeys. Endoneurial microvessels did not show either endothelial or pericyte proliferation or basement membrane thickening. The results suggest that chronically STZ-diabetic Japanese monkeys with the duration of diabetes up to 36 months might be useful for studying diabetic axonopathy, but do not closely mimic the nerve pathology found in human diabetic neuropathy.

We studied the effect of the duration of diabetic state on insulin action in skeletal muscle by measuring insulin binding, 2-deoxyglucose uptake, and intracellular glucose metabolism in isolated soleus muscles from streptozotocin-induced diabetic rats. Insulin binding to soleus muscles from diabetic rats was increased over that from controls. Glucose transport activity was determined by measuring the 2-deoxyglucose uptake at the concentration of 1 mmol/L at 25 degrees C. In the rats with diabetes of one week duration, insulin-stimulated 2-deoxyglucose uptake was not impaired, whereas basal 2-deoxyglucose uptake was decreased. However, the diabetic rats with two weeks duration revealed a 35.6% decrease in the insulin-stimulated 2-deoxyglucose uptake. Furthermore, four week duration of diabetic state led to a 60% decrease both in basal and insulin-stimulated 2-deoxyglucose uptake. Total glucose utilization was estimated as the total amount of glucose incorporated into muscle and lactate released into the medium following incubation at 37 degrees C, with 5 mmol/L glucose. The diabetic rats with one week duration did not demonstrate any changes in total glucose utilization both in basal and insulin-stimulated state. However more than two weeks duration of diabetes led to a 30% to 35% decrease both in basal and insulin-stimulated total glucose utilization, similar to the findings in the 2-deoxyglucose uptake study. We concluded that prolonged insulinopenia led to decreased glucose transport and intracellular glucose metabolism and resulted in insulin resistance in skeletal muscles.

A highly sensitive and simplified method for the differential determination of serum ketone bodies has been developed. Serum was deproteinized with perchloric acid, and acetoacetate contained in the supernate was reacted with newly synthesized p-nitrobenzene diazonium fluoroborate at 37 degrees C for 10 min. The formed hydrazo compound was converted by alkali to the more stable azo compound which has a peak absorbance at 645 nm. For the determination of 3-hydroxybutyrate, this was enzymatically converted to acetoacetate using 3-hydroxybutyrate dehydrogenase, LDH, NAD and pyruvate. Using 0.2 ml serum, acetoacetate and 3-hydroxybutyrate could be quantitated in 30 min. The described method is five times more sensitive than the enzymatic photometric method and can detect individual ketone bodies at concentrations as low as 20 mumol/l. Differential determination of serum levels of ketone bodies is clinically useful for the diagnosis of type 1 diabetes and in monitoring diabetic control.

[SerB24]-insulin, the second structurally abnormal mutant insulin, and [SerB25]-insulin were semisynthesized and were studied for receptor binding and biological activity. Receptor binding and biological activity determined by its ability to increase 2-deoxy-glucose uptake in rat adipocytes were 0.7-3% of native insulin for [SerB24]-insulin and 3-8% for [SerB25]-insulin. Negative cooperative effect of these analogues was also markedly decreased. Immunoreactivity of [SerB24]-insulin was decreased whereas that of [SerB25]-insulin was normal. Markedly decreased receptor binding of [SerB24]-insulin appeared to be due to substitution of hydrophobic amino acid, Phe, with a polar amino acid, Ser, at B24.

Chronic idiopathic neutropenia can occur in spite of the normocellular bone marrow in myeloid series with or without anti-neutrophilic antibody. We report a patient with chronic neutropenia and severe polyclonal hypergammaglobulinemia. The patient demonstrated a positive anti-neutrophil antibody by fluorocytometry, although granulocyte-specific anti-nuclear factor and anti-stem cell (CFU-GM) antibody were negative. Thus, neutropenia of this patient appeared to be due to the antibody-mediated destruction of neutrophils. Both neutropenia and hypergammaglobulinemia were normalized by the administration of prednisone.

We studied the effect of chronic exposure to insulin on insulin receptors of cultured lymphocytes (RPMI-1788 line). The cells treated with insulin (2 micrograms/ml) at 37 degrees C for 12 h, showed a 36.5% decrease in the number of binding sites. Solubilized extract from the cells treated with insulin showed a 35.9% decrease of binding capacity, suggesting that insulin exposure induced the loss of total (cell surface and intracellular) receptors. Insulin-induced loss of receptors was blocked by chloroquine, suggesting that receptor loss is mediated by a chloroquine sensitive pathway. Bacitracin, which inhibited the insulin degradation, had no effect on insulin-induced receptor loss in this cell line. We also found that vitamin K5, one of the insulin mimickers, induced a 31.5% loss of insulin receptors. Therefore, the post-receptor process appeared to mediate down regulation. In cultured lymphocytes, insulin exposure caused a significant loss of total receptors, suggesting that insulin-induced receptor loss may be due to receptor degradation. Insulin-induced receptor loss is mediated by a chloroquine sensitive pathway, and is related to the post-binding process stimulated by vitamin K5.

We studied insulin binding to cultured differentiating muscle cell line L6. Insulin binding to the cells reached a plateau after incubation with 125I-insulin for 4 h at 22 degrees C, and was at an optimum at pH 7.8. Preincubation with 10 microM of hydrocortisone for 36 h at 37 degrees C resulted in significantly increased insulin binding (1.73 +/- 0.12 ng/mg protein for treated cells vs. 1.13 +/- 0.025 ng/mg protein for control cells, mean +/- SD, P less than 0.001). Preincubation with 1 microM of hydrocortisone or 1 microM of dexamethasone also led to increased binding. The number of insulin-binding sites per cell increased 2.5-fold in glucocorticoid-treated cells (9.7 X 10(3) sites/cell for treated vs. 3.8 X 10(3) sites/cell for control cells). Preincubation with trifluoperazine (5 microM), a calmodulin inhibitor, did not affect insulin binding to the cells. These results indicate that glucocorticoid might have some important role in regulating the number of insulin receptors in L6 muscle cells.

クロイツフェルトヤコブ病(CJD)類似のミオクロヌス,周期性同期性発作波(PSD),進行性脳萎縮を認めた低血糖昏睡の1例を報告した.症例は69才男性で痙〓,意識障害を主訴に入院.来院時8mg/dlの著明な低血糖を呈し,血糖改善後も意識の改善はなく失外套症候群へと移行した.数年来睡眠薬による神経症状が先行しミオクロヌスやPSDを認め, CTで長期間進行する脳萎縮を認めた.経過がCJDと極めて類似しており生前CJDを否定する事が困難であったが,剖検により低血糖に伴う脳障害と診断された.低血糖昏睡例の臨床経過,脳波, CTを長期間経時的に観察した報告は少ない.本例はCJD類似の特異な経過をとっており興味ある症例と考え報告した.

Insulin analogues with different amino acids, including threonine, alanine, L-leucine, D-leucine, L-leucine amide, phenylalanine, tri-alanine, or desalanine, at the B-30 position were semisynthesized from pork insulin by the new enzymatic method. The order of ability of the insulin analogues to bind to anti-insulin sera was [AlaB-30] greater than desalanine greater than [ThrB-30] greater than [Ala-Ala-AlaB-30] greater than [D-LeuB-30], [Leu-NH2B-30],[PheB-30] greater than desoctapeptide greater than or equal to [LeuB-30]. The ability of insulin analogues with different amino acids at B-30 to bind to receptors, as well as their biologic potency tested with glucose uptake in isolated rat adipocytes, was comparable among the analogues. These results suggest that [LeuB-30]-insulin demonstrated the least immunoreactivity and has full activity in receptor binding and biologic effect, and that it may be useful for treatment of anti-insulin antibody-mediated insulin resistance.

The in vitro effect of glucocorticoid on insulin binding and glucose transport was studied with rat adipocytes. Isolated rat adipocytes were incubated with or without 0.70 microgram/ml (1.9 mumol) of hydrocortisone in TCM 199 medium at 37 degrees C, 5% CO2/95% air (v/v), pH 7.4, for 2, 4, and 8 h, and then fat cell insulin binding and insulin-stimulated 3-O-methylglucose transport were measured. Hydrocortisone did not affect insulin binding in terms of affinity or receptor number. Glucose transport in the absence of insulin was significantly decreased at the incubation time of 2 h and continued to decrease up to 8 h of incubation with hydrocortisone. Decreased insulin sensitivity of glucose transport (i.e., a right-ward shift of the dose response curve) was also demonstrated after 2 h incubation with hydrocortisone, and the ED50 of insulin was maximally increased at 4 h of incubation (0.53 ng/ml for treated vs. 0.22 ng/ml for control cells). Maximal insulin responsiveness was also significantly decreased in treated cells after 8 h incubation with hydrocortisone. When percent maximum glucose transport was expressed relative to receptor-bound insulin, the ED50 values of treated and control cells were 10.5 and 7.2 pg of bound insulin, per 2 X 10(5) cells, respectively. Thus, it was evident that glucocorticoid induced a post-receptor coupling defect in the signal transmission of insulin-receptor complex.

Focal hyperplasia of intracytoplasmic filaments of 100A in diameter was observed within chief cells of the parathyroid gland in dogs treated with nalidixic acid. The structure, as a rule, was located in the neighborhood of the nucleus and no other cell organelles were detected within it. Its size had a wide spectrum from a small part of the cytoplasm to as large as half a cell. Golgi apparatus and rough endoplasmic reticulum in the involved cells had a tendency to atrophy. These cells occasionally contained less secretory granules. Lipid droplets are diffusely increased. The pathogenesis and significance of the present intracytoplasmic filaments remain to be determined. However, as lipid deposition, atrophy of Golgi apparatus, poorly developed rough endoplasmic reticulum occur in a hypofunctional or degenerative state, it might be possible that filamentous hyperplasia is closely associated with that state.

We studied insulin degradation in human cultured lymphocytes (RPMI-1788 line) with a small but significant number of lysosomes under the electron microscope. Insulin degradation determined by the TCA solubility method was 64.6 +/- 1.2% (mean +/- SEM) at a trace concentration after the incubation with 2.0 x 10(7) cells (4.0 x 10(7) cells/ml) for 60 min at 37 degrees C. Because insulin degradation was 54.6 +/- 7.0% in the cell-free buffer in which 2.0 x 10(7) cells were previously incubated, most of the insulin was degraded outside of the cells. Gel filtration of the radioactive materials also revealed that most of the labeled insulin in the medium was degraded, and the main peak of the cell-associated radioactivities was intact labeled insulin. Chloroquine, a lysosomotropic agent, failed not only to increase insulin binding but also to decrease the insulin degradation. Other lysosomal protease inhibitors, antipain and leupeptin had also no effect on insulin degradation. In contrast, bacitracin (500 micrograms/ml) significantly decreased the insulin degradation analyzed by TCA solubility, receptor-rebinding, and the gel filtration method. These results suggest that insulin molecules are degraded by the enzymes leaked from the cells. The non-receptor mediated process, which is the bacitracin sensitive pathway, might be a general mechanism of insulin degradation in human cultured lymphocytes in vitro.

We compared A-14 and A-19 125I-labelled insulin in receptor-binding and degradation. Percent receptor-binding of A-14 and A-19 125I-labelled insulin to 2.4 X 10(9)/ml erythrocytes after 210 min incubation at 15 degrees C was 7.8 and 4.9%, respectively. Percent insulin-receptor binding of A-14 insulin was 1.6 times greater than that of A-19 insulin. A similar result was obtained in an adipocytes insulin binding study. Percent receptor-binding of A-14 and A-19 insulin to 2 X 10(5)/ml fat cells after 30 min incubation in the above buffer was 3.9 and 2.4%, respectively. Degradation of A-14 and A-19 insulin in rat adipocytes was also studied by molecular sieve column chromatography. Isolated rat adipocytes were allowed to associate with A-14 and A-19 125I-insulin for 60 min at 37 degrees C, pH 8.0 in a HEPES-phosphate buffer, and then cells were separated from the buffer by centrifugation. After solubilization with triton X-100, both the solubilized cells and the incubation medium were applied to the Bio-Gel P-30 column to assess the insulin degradation. Degradation of A-14 125I-insulin by the isolated rat adipocytes was 1.6 times greater than that of A-19 125I-insulin. Furthermore, the peak which was thought to be intermediate degradation products of insulin was obtained between the peak of intact insulin and that of 125I-tyrosine. Such a peak of intermediates was much smaller in the incubation media than in the cell-associated materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloxan diabetic rats with fasting blood glucose levels above 300mg/100ml were treated with oral administration of water-in-oil-in-water (W/O/W) insulin emulsions at a dose of 50 U/100g body weight, three times daily for 10 to 14 days. The course of diabetes was followed by determinations of glucose levels in blood and urine.During treatment with oral W/O/W insulin emulsions, daily excretion of urinary glucose decreased by about 30 to 40%(2 to 3g/day) in all of the five rats studied, and returned to the pre-treatment levels after the treatment being discontinued. During treatment, a significant reduction in fasting blood glucose levels was observed in 4 out of 5 rats, giving the decrease by 18 to 44%. Quantitative estimates suggested that the effectiveness of 50 U/100g of oral W/O/W insulin emulsions was comparable to that after intramuscular regular insulin at a dose of 0.5 U/100g.Although oral W/O/W insulin emulsions are still of low efficiency, these results would indicate that diabetes can be controlled by effective oral insulin preparations.

[D-Phe B24 ]- and [D-Phe B25 ]-human insulin were semisynthesized from porcine insulin by enzyme assisted coupling method. Receptor binding ability of [D-Phe B24 ]- and [D-Phe B25 ]-insulin was 180% and 4%, respectively, of that of human insulin. Increased affinity of [D-Phe B24 ]-insulin was ascribed to markedly decreased dissociation rate in binding to human cultured lymphocytes. Negative cooperative effect of [D-Phe B24 ]insulin was also increased to twice of that of human insulin. Biological activity of these analogues was assessed by 2-deoxy-glucose uptake studies in isolated adipocytes and the ability of [D-Phe B24 ]- and [D-Phe B25 ]-insulin was 140% and 4%, respectively, of that of human insulin. These findings suggest that B25 L-Phe is more crucial for receptor binding and that [D-Phe B24 ]-insulin is the first semisynthetic insulin to show increased affinity for insulin receptors.

The long-term in vitro effects of insulin on insulin binding and glucose transport were studied using rat adipocytes in a time-dependent manner. Isolated fat cells were incubated with insulin (100 ng/ml) for 4, 8 and 24 h in a TCM 199 medium, at 37 degrees C, and then insulin binding (37 degrees C, 60 min) and 3-O-methylglucose transport (37 degrees C, 2 s) were determined. Decreased insulin binding was demonstrated in the cells incubated with insulin for 8 h, and Scatchard analysis revealed that receptor number was decreased to 61.7% of that of control cells. Thus, insulin-induced down regulation of receptors was evident after 8 h incubation with insulin. On the other hand, 8 h incubation with insulin resulted in markedly increased basal (i.e., in the absence of insulin) glucose transport up to 246% of control values. In the cells incubated with insulin for 24 h, maximally insulin-stimulated glucose transport was significantly increased up to 248% of control value. Thus, these results suggested that insulin-induced down regulation of receptors appeared to be coupled with increased cell-surface glucose transporters, and that there was a time-lag between down regulation of insulin receptors and increase of available glucose transporters in the plasma membrane.

Two sisters presented with severe insulin resistance and markedly decreased insulin binding to erythrocytes, cultured fibroblasts and transformed lymphocytes. The dose-response curve of insulin-stimulated amino acid uptake in the fibroblasts was shifted to the right. The molecular weight of the insulin receptor on the transformed lymphocytes from the patients was 210,000 and could not be dissociated to α- and β-subunits by dithiothreitol treatment. However, the proreceptor was cleaved by trypsin and this led to the production of α-subunit with normal insulin binding. We performed cDNA sequence analysis of the cleavage site of the insulin proreceptor from the patients. The polymerase chain reaction was used to obtain a large amount of cDNA coding for the region including the interconnecting site. A thermostable DNA polymerase, Taq polymerase, successfully produced enough cDNA for the region to be sequenced. The results showed an AG G (Arg) to AG T (Ser) point mutation, resulting in the change of the interconnecting sequence of the two subunits from -Arg-Lys-Arg- Arg - to -Arg-Lys-Arg- Ser -. These results suggest that the tertiary structure change of the cleavage site leads to production of unprocessed insulin proreceptors.

A new potentiator of insulin action, 5-[4-(1-methylcyclohexylmethoxy)-benzyl]thiazolidine-2,4-dione, was tested for activation of insulin action in vitro. The agent (50 mg.kg−1.day−1) was orally administered to rats for 14 days and adipocytes from treated rats were used to assess insulin-binding, glucose uptake and glucose oxidation. In obese rats, the agent increased glucose uptake and oxidation without any change in insulin binding, whereas in lean or streptozotocin-treated rats it failed to increase glucose metabolism. Fat tissues were cultured with the agent for 24 h and were tested for insulin action. In the presence of insulin (10 ng/ml) in the culture media, the agent increased glucose oxidation in these cells without any change in insulin binding. However, without insulin in the culture media the agent did not increase glucose oxidation. Thus, the agent appeared to potentiate insulin action at the post receptor process.

A rapid paper-strip test for the semiquantitating 3-hydroxybutyrate (3-OHBA) has been developed. The color develops within 5 min after applying the serum to the paper strip, and the purple color was read either visually or by reflectance meter. This can detect 3-OHBA levels as low as 0.1 mmol/L up to 2.0 mmol/L. The more concentrated sample can be measured on serial dilution. Clinical usefulness has been tested in a summer camp for insulin-dependent diabetic children as well as in a routine diabetes clinic. Serum 3-OHBA levels ranged from > 100 µumol/L to 4 mmol/L in all the subjects before breakfast in a summer camp. In four subjects, 3-OHBA was elevated to the level of 2–4 mmol/L, and only one of these four subjects exhibited ketonuria by nitroprusside test. In a diabetes clinic, a new paper-strip test for 3-OHBA has revealed ketonemia in 34 (74%) of 46 diabetic subjects, while nitro-prusside test revealed ketonemia in only 4 (13%). The present paper-strip test for 3-OHBA is sensitive enough to detect levels as low as 0.1 mmol/L and is clinically useful for rapid detection of ketosis proneness as well as for monitoring of diabetes control.

Conversion of C 14 into fatty acids of liver and carcass from acetate-2-C 14 , and into blood glucose and liver glycogen from DL-alanine-1-C 14 were studied during and following a dynamic phase of obesity caused in rats by feeding of high caloric diet. (1) There were found to be no significant differences among normal rats and rats in dynamic or static (postdynamic) phases in cumulative expired C 14 O 2 after injection of acetate-2-C 14 . (2) Conversion of C 14 from acetate-2-C 14 into fatty acids of the liver and carcass was increased in the dynamic phase and decreased in the static phase. (3) Incorporation of C 14 from DL-alanine-I-C 14 into blood glucose and liver glycogen was found to be increased in the dynamic and static phases of high-caloric fed rats.

The cytoplasmic reduction-oxidation state of some NAD-linked reactions has been investigated in the liver in vivo under normal and diabetic conditions with or without CoQ7 administration.1. In the liver, the close relationships among lactate/pyruvate, malate/oxaloacetate and glycerol-1-phosphate/dihydroxyacetone phosphate ratios were found in all the metabolic conditions studied. In diabetic rats, these systems were found to be more reduced.2. CoQ7 administration to diabetic rats for four days intramuscularly tended to restore these ratios to normal. This effect was followed by a significant drop in malate concentration.Present findings would indicate that the effect of CoQ7 on the reduced state in diabetic rats seems to be mediated via malate removal.

1. The CoQ content of whole rat liver increased significantly as compared with the control after the intramuscular administration of CoQ7, CoQ9 or CoQ10, but increased slightly after the administration of CoQ2 or CoQ6. In the mitochondrial fraction, CoQ content increased only after the administration of CoQ7 or CoQ9. After the administration of CoQ compounds, paper chromatography of the liver extract showed a corresponding increase of CoQ.2. Twenty-four hours after giving CoQ7-14C to rats, the percentage recovery in the liver administered was found to be 12.3±0.47% of the dose of 14C administered intramuscularly or 11.8±1.37% of those given orally. When the CoQ fraction was developed paperchromatographically, the radioactivity on the actigram was found in the CoQ7 portion exclusively.

The intestinal absorption of insulin has been studied in a preparation of isolated rabbit intestine in which artificial plasma is circulated through normal vascular channels. After insulin in doses of 100, 200, and 440 U. was introduced into the intestinal lumen, its appearancein the venous effluent was measured immunologically during perfusion for two hours. Insulin gradually appeared in the venous effluent and reached a peak fifty to ninety minutes after the perfusion was started. The proportion of insulin absorbed was 6.2 to 9.2 per cent with a dose of 100 U., 5.9 to 15.6 per cent with 200 U., and 8.9 to 15.9 per cent with 440 U. The amount of insulin added significantly correlated with the total amount of insulin absorbed from the intestine. The biologic activity in the fraction absorbed was equivalent to that obtained immunologically. In the venous effluent, insulin component was also identified by the relative mobility similar to crystalline insulin on acrylamide gel electrophoresis. Although the intestinal absorption in this system does not duplicate physiologic absorption, these results indicate that a considerable portion of insulin can be absorbed from the intestine in a physiologically active form.

Thioctic acid was determined microbiologically using Streptococcus faecalis 10 C1. The serum level of thioctic acid was frequently found to be reduced in patients with diseases of the liver, especially in those with liver cirrhosis. In patients with severe diabetes mellitus and in some patients with polyneuritis or arteriosclerosis, the serum level of thioctic acid was also found to be decreased.

The changes in plasma lipoprotein lipase activity after intravenous injection of dextran sulfate, which stimulates release of lipoprotein lipase, have been studied in forty two diabetic patients, eight obese subjects and eleven normal subjects. In normal subjects, the response of lipoprotein lipase activity to dextran sulfate averaged 5.7±0.6 (S.E.) μEq. FFA/ml. at ten minutes and 6.5±1.2 (S.E.) μEq. FFA/ml. at twenty minutes. A significantly decreased response of lipoprotein lipase activity to dextran sulfate was found in obese subjects and in diabetic patients, especially in those with hypertriglyceridemia. No correlation was observed between the cholesterol level and lipoprotein lipase activity. No significant relation between changes of lipoprotein lipase activity and the incidence of diabetic complications was found.

1. Urinary excretion of PaA and the increase in the excretion of the vitamin following pantothenate administration were measured in 52 patients with various liver damages. Mutual relations with various liver functions were also studied.2. Both urinary PaA and the increase in excretion following intramuscular administration of the vitamin were reduced in most patients in comparison with those in normal adults.In relatively severe cases, increase in PaA excretion following intramuscular administration of the vitamin was frequently found to be greater than that of normal persons.3. Correlation was found between PaA excretion and various liver functions, especially, TTT, serum cholesterol ester ratio, hippuric acid synthesis and blood pyruvate level.4. The results mentioned above led to the conclusion that a metabolic disturbance of PaA may exist in liver damages leading to the impairment of liver functions, especially, hippuric acid synthesis, and the metabolism of α-keto acid and cholesterol.

C14-incorporation into blood glucose and liver glycogen from C14-labelled alanine was studied in rats with acute or chronic CCl4 liver damage.In rats with CCl4 liver damage, C14-incorporation from alanine into blood glucose and liver glycogen was found to be decreased, especially in rats with acute CCl4 liver damage. Such a disturbed C14-incorporation was improved by the administration of 2.5mg of cortisone to rats with chronic CCl4 poisoning. However, in rats with acute CCl4 liver damage, cortisone treatment caused a marked increase in C14-incorporation into blood glucose and failed to increase C14-incorporation into liver glycogen.The latter finding may be related to the increased incidence of steroid diabetes in patients with liver damage.

1. Lipoic acid or lipoamide administered orally to animals seemed to be easily absorbed from the digestive tract and to be eliminated in the urine largely as the oxidation products of these substances.2. Lipoamide was easily converted to lipoic acid both in the in vitro and in vivo experiments.3. Urinary excretion of S35-compounds, after administering S35-lipoic acid or S35-lipoamide, was found to be increased in the rats poisoned with CCl4 or those with alloxan diabetes as compared with normal rats.

One or two hours after intraperitoneal injection of trace amounts of glucose-1-H3 and glucose-1-C14 obese-hyperglycemic mice of the Bar Harbor strain converted five to ten times as much of both radioisotopes to total fatty acids of the liver and two to four times as much to total fatty acids of the remaining carcass as their lean siblings. The obese mice generally oxidized glucose-1-C14 to C14O2 and glucose-1-H3 to H3OH at rates equal to those of the lean mice. At 2 hr, 40–45% of the glucose-C14 had been converted to C14O2 and 75–80% of the glucose-1-H3 to H3OH. The maximum conversion of tritium to liver fatty acids was about .4% of the dose at 1 hr and of C14 about .25% of the dose at 1 hr, while for the carcass fatty acids the highest conversion were at 2 hr with about 2.0% of the dose of glucose-1-H3 and 1.8% of the dose of glucose-1-C14.

Using an everted sac technique, the intestinal absorption of insulin in the rabbit has been investigated.Insulin was shown to cross the intestinal wall, as demonstrated by the immunoreactive insulin inside the sacs (serosal fluid). The rate of insulin transference for a period of one hr was small, corresponding to approximately 0.1% of the insulin added to the mucosal fluid. This rate was not inhibited by the addition of 2, 4-dinitrophenol.The small transference rate would indicate that the submucosal and muscular tissues of the intestinal wall, in the absence of vascular perfusion, present a barrier to the movement of large molecular weight substances.

Plasma immunoreactive insulin has been assayed in blood samples drawn simultaneously from portal and peripheral venous blood following an injection of insulin into the ligated intestine of rabbits. The portal venous blood flow has also been measured using a perivascular electromagnetic flow transducer to estimate the amount of insulin absorbed. Following an injection of insulin with a dose of 100 U/kg, portal vein insulin concentration increased to the peak of 330 μU/ml in the ligated jejunal loop experiments, and 1280 μU/ml in the ligated ileal loop experiments. Both in the jejunal and in the ileal loop experiments, the peak insulin concentration in the portal vein was twice that in the peripheral vein. A significant correlation between portal and peripheral vein insulin responses (as reflected by the area) was noted. By multiplying the differences in the two venous insulin concentrations by the portal venous blood flow, the peak absorption was observed at a rate of 7.0 mU/kg/min in the jejunum, and 21.2...