Gerald A. Wrenshall

Correlation of beta-cell granulation with extractable insulin of the pancreas; studies in adult human diabetics and nondiabetics.

The authors have previously reported the degree of correlation between the amount of extractable insulin and the numbers of beta cell granules present in the pancreases of a series of ninety-two patients coming to autopsy in the Department of Pathology, University of Toronto (Hartroft; Wrenshall, Bogoch, and Ritchie). One-half the patients were known diabetics and the other half nondiabetics. The coefficient of linear correlation between the amounts of extractable insulin and the beta cell granulation, although statistically significant, was low (0.48). Since the appearance of these reports, we have not only added more cases to the series, but also have obtained new histologic data for all cases. The technic of measuring extractable insulin in the pancreases of the cases added to the series since 1950 was the same as that employed for the original members (Wrenshall, Bogoch, and Ritchie). We are now able to report that the coefficient of linear correlation between numbers of beta cell granules, estimated in sections stained by Wilsons modification of the Gomori aldehyde-fuchsin method, and the amount of extractable insulin obtained from pancreases of 86 nondiabetic human subjects is 0.584; for 80 diabetics the comparable figure is 0.680. Because these positive correlation coefficients differ very significantly from zero,

Acetone in the Breath: A Study of Acetone Exhalation in Diabetic and Nondiabetic Human Subjects

While it has long been suspected that free acetone may be a physiological metabolite, experimental evidence for its presence in nonfasting normal human subjects has remained inconclusive. This is probably due to the lack of specificity of known methods for determination of minute amounts of acetone in blood and urine (Weichselbaum and Somogyi, 1941, and others), for if free acetone is present in these fluids, it is there normally in very low concentration. Where higher concentrations of acetone are present, however, as in the uncontrolled diabetic subject, its identity can readily be established in blood, urine and exhaled air. Widmark (1920) concluded that passage of the free acetone of blood into the alveolar air of diabetic subjects takes place in conformity with the laws of diffusion. We have undertaken a study of the free acetone content of the exhaled air from nonfasting diabetic and normal subjects, using two widely dissimilar yet highly sensitive methods for the determination of free acetone in aliquots of the same sample of condensed exhaled vapor. One of these, a physical method using a recording mass spectrometer, was mass-specific for acetone. The second was the chemical micromethod of Greenberg and Lester (1944).

Insulin Extractable from the Pancreas and Islet Cell Histology: Comparative Studies in Spontaneous Diabetes in Dogs and Human Subjects

The characteristics of diabetes mellitus in man have long been compared, either directly or by inference, with those of diabetes produced in animals by experimental means. From the earliest studies in this field by von Mering and Minkowski1, in the work leading to the discovery of insulin2 (1921), and in many later investigations, the dog has occupied a prominent and productive place amongst experimental animals. In recent years, special aspects of the spontaneous diabetes of dogs have come under study in this laboratory and in that of Professor Henry Ricketts in Chicago. It is the purpose of this paper to examine the available data to determine the degree to which the spontaneous and the experimentally induced diabetes mellitus of dogs correspond with each other and with the spontaneous diabetes mellitus of man, in terms of the insulin extractable from the pancreas and the histological state of the islands of Langerhans. The relationship of these factors to the diabetic state with which they are associated will also be considered.

Effects of sudden deprivation and restoration of insulin secretion on glucose metabolism in dogs.

Fourteen subtotally depancreatized aglycosuric dogs had the remaining pedunculated uncinate process enclosed in plastic casing and grafted subcutaneously. After one week the pedicle of the auto graft was clamped for thirty to sixty minutes. In seven dogs given intravenous glucose at the time of clamping, diabetes-like changes in glucose tolerance occurred which increased in magnitude with increasing duration of deprivation of exogenous insulin. In seven fasting dogs the blood glucose level was rising in the four- to tenminute interval after clamping. In three such dogs (one under local and two under Nembutal anesthesia) the method of successive measured injections of tracer (C-14-glucose U.L.) showed that the rate of glucose appearance had doubled and the rate of its disappearance was decreased to one third at one to thirteen minutes after clamping, resulting in high rates of accumulation of body glucose. The initial increase in the rate of glucose production appears to result from glycogenolysis. Restoration of blood flow through the autograft (unclamping) caused a prompt decrease in rate of appearance of unlabeled glucose and increase in its rate of disappearance, resulting in restoration of these rates to their preclamping values within fifteen hours, and to a restored tolerance for intravenous glucose. The rapidity of these rate changes at clamping and unclamping demonstrates the importance of the continuous secretion of native insulin to prevent glucose accumulation in the partially depancreatized dog.

Absolute Rates of Glucose Production, Accumulation, and Utilization in the Dog at Pancreatectomy and Thereafter

1. The method of successive measured injections of tracer has been used to determine absolute rates of glucose appearance (production), accumulation, disappearance, excretion and utilization in six fasting bitches at times before and after total pancreatectomy. 2. The rate of glucose utilization underwent a great reduction within minutes following pancreatectomy. 3. In contrast, the rate of glucose production did not change greatly at this time. 4. As a consequence, there was a rapid accumulation of glucose in the dog when measured in terms of the amount which intermixed with the injected tracer, and as seen less directly by a rise in the concentration of glucose in the blood plasma. 5. The increase in blood glucose level following pancreatectomy was accompanied by a restoration in the average rate of glucose utilization to about two thirds of its value before pancreatectomy, and by glycosuria. 6. Both the rate of production and that of utilization increased moderately during the first one or two days following total pancreatectomy. Thereafter they decreased progressively and ketonuria became severe. 7. No effect of general anesthesia (Nembutal) was noted on the above patterns of change in glucose rates.

Reports on studies with carbutamide and tolbutamide done at the Charles H. Best Institute, University of Toronto.

The combined report that follows consists of summaries of work recently done with carbutamide and tolbutamide in five dfferent sections of the Charles H. Best Institute. I have been delegated to summarize and present the findings of the research teams involved. The names of the contributors are indicated with each summary. D. W Clarke has measured glycogen levels in rat diaphragms before and during incubation in vitro following the in vivo administration of carbutamide or tolbutamide. Six groups of normal rats received daily injections of either saline, 50 mg. carbutamide, 50 mg. tolbutamide, 10 mg. cortisone, carbutamide and cortisone, or tolbutamide and cortisone. After 14 days, the rats were killed and the diaphragms were removed for a determination of their initial glycogen. The amounts of glycogen synthesized after incubations in a glucose-containing medium were also determined. With 7 animals per group, the values for the initial glycogen levels were as shown in TABLE 1. Treatment with carbutamide significantly increases the initial glycogen. The apparent increase with tolbutamide is not statistically significant, although it must be considered suggestive. The effect of cortisone treatment was to increase initial muscle glycogen. There were no interactions between cortisone and either tolbutamide or carbutamide. In many cases there was actually less glycogen after than before incubation, and these cases are shown in TABLE 2 as negative values for net glycogen synthesis. The greater glycogen loss in the carbutamide-treated animals than in the saline-injected controls is statistically significant. The results with the tolbutamide-treated animals are not significantly different from those obtained with control animals. It was demonstrated previously that there is no direct effect of carbutaniide in stimulating glycogen synthesis of the diaphragm.’ The effect noted Average values for net glycogen synthesis are shown in TABLE 2.