ALCOHOL HYPOGLYCEMIA. IV. CURRENT CONCEPTS OF ITS PATHOGENESIS

A novel metabolic disorder in the degradation pathway of endogenous methanol due to a mutation in the gene of alcohol dehydrogenase

BACKGROUND

A small amount of methanol is produced endogenously in the human body but it is efficiently metabolized by alcohol dehydrogenase (ADH) and other enzymes, and the products eliminated without harm. In this study, we present a new entity of inborn error of methanol metabolism due to a mutation in the ADH1C gene coding for the γ subunit that is part of several ADH isoenzymes.

RESULTS

This disorder was discovered in an 11.58-year-old boy. During one 9-month hospital admission, he had periods of 1-4 days during which he was comatose, and between these periods he was sometimes verbose and euphoric, and had ataxia, dysarthria. Following hemodialysis treatments, he became conscious and appeared healthy. Organ evaluations and his laboratory tests were normal. Toxicological evaluation of his blood showed a high methanol level [12.2 mg/dL (3.8 mmol/L), normal range up to 3.5 mg/dL (1.09 mmol/L) while the formaldehyde level was undetectable. The finding of liver function tests that were within normal limits, coupled with a normal eye examination and size of the liver, elevated blood methanol levels and an undetectable formaldehyde level, suggested ADH insufficiency. Adding zinc to the drug regimen 15 mg/daily dramatically reduced the patient's methanol level and alleviated the abnormal symptoms. When zinc supplementation was discontinued, the patient relapsed into a coma and hemodialysis was once again required. A homozygous mutation in ADH1C gene located at exon 3 was found, and both parents were heterozygous for this mutation.

CONCLUSION

Accumulation of methanol due to mutation in ADH1C gene may result in drunkenness and ataxia, and leads to coma. This condition can be successfully treated with zinc supplementation as the cofactor of ADH.

Nutrition in alcohol-related liver disease: Physiopathology and management

Malnutrition encompassing both macro- and micro-nutrient deficiency, remains one of the most frequent complications of alcohol-related liver disease (ArLD). Protein-energy malnutrition can cause significant complications including sarcopenia, frailty and immunodepression in cirrhotic patients. Malnutrition reduces patient’s survival and negatively affects the quality of life of individuals with ArLD. Moreover, nutritional deficit increases the likelihood of hepatic decompensation in cirrhosis. Prompt recognition of at-risk individuals, early diagnosis and treatment of malnutrition remains a key component of ArLD management. In this review, we describe the pathophysiology of malnutrition in ArLD, review the screening tools available for nutritional assessment and discuss nutritional management strategies relevant to the different stages of ArLD, ranging from acute alcoholic hepatitis through to decompensated end stage liver disease.

Impact of Alcohol on Glycemic Control and Insulin Action

Alcohol has profound effects on tissue and whole-body fuel metabolism which contribute to the increased morbidity and mortality in individuals with alcohol use disorder. This review focuses on the glucose metabolic effects of alcohol, primarily in the muscle, liver and adipose tissue, under basal postabsorptive conditions and in response to insulin stimulation. While there is a relatively extensive literature in this area, results are often discordant and extrapolating between models and tissues is fraught with uncertainty. Comparisons between data generated in experimental cell and animals systems will be contrasted with that obtained from human subjects as often times results differ. Further, the nutritional status is also an important component of the sometimes divergent findings pertaining to the effects of alcohol on the regulation of insulin and glucose metabolism. This work is relevant as the contribution of alcohol intake to the development or exacerbation of type 2 diabetes remains ill-defined and a multi-systems approach is likely needed as both alcohol and diabetes affect multiple targets within the body.

Consuming a small-moderate dose of red wine alone can alter the glucose–insulin relationship

The aim in the present study was to assess the effect of small-moderate red wine ingestion on the level of serum insulin and plasma glucose when nutritional status is varied. Twenty nondiabetic males (19–22 years) participated in the study. In the fasting trial, all participants underwent a 6 h fast prior to consuming 4 standard units of red wine (40 g alcohol) or the equivalent amount of placebo as dealcoholized wine (containing <0.5% alcohol, 0% resveratrol) over a 135 min period. Alternatively, in the feeding trial, participants consumed food for 45 min prior to ingesting 4 standard units of red wine (40 g alcohol) or placebo over 135 min. Serum insulin and plasma glucose were assessed at regular 45 min intervals during all trials. The results showed a significant decrease in the level of serum insulin and no significant change in plasma glucose concentration in the fasting trial. Alternatively, a significant alcohol-induced decrease in plasma glucose and no change in serum insulin occurred when red wine alone was consumed after food. It was concluded that red wine can alter the glucose–insulin relationship and ingesting red wine alone (without food) should not be encouraged in nondiabetic individuals.

Does a disturbed insulin release promote hypoglycemia in alcoholics?

Peroral glucose tolerance tests, i.v. tolbutamide tests and postfasting alcohol tests were performed in three alcoholics, who had been admitted to hospital with hypoglycemic symptoms. In one one case the findings indicated extreme insulin sensitivity and in two cases there was evidence of a distrubed insulin release. These two factors might have a bearing on the occurrence of hypoglycemic symptoms in alcoholics.

Lipid peroxide levels and antioxidant status in alcoholic liver disease

The present study was conducted to evaluate some of the components of antioxidant defense system and oxidative damage in 20 male patients of alcoholic liver disease (ALD). The results were compared with 20 healthy male smokers and 20 healthy male non-smokers volunteers. Patients were subjected to detailed clinical examination and laboratory investigations. Blood samples were collected for estimating reduced glutathione (GSH), total thiols (T-SH) malondialdehyde (MDA), transaminases (AST, ALT), glutathione-S-transferease (GST) and gammaglutamyl transferase (GGT). Serum aspartate amino transferase (AST)/alanine amino transferase (ALT) ratio was significantly (p<0.01) reduced in ALD patients as compared to the controls. However, the core of utility of MDA and GST was found to be significantly (p<0.01) increased in ALD patients compared to controls. There was a significant negative correlation of MDA with both GSH and TSH. Plasma GGT levels were significantly (p<0.01) increased in alcoholics and the enzyme showed a significant positive correlation with MDA. These results give enough evidence of increased oxidative stress and compromised antioxidant defense system in patients with ALD.

The acute impact of ethanol on glucose, insulin, triacylglycerol,and free fatty acid responses and insulin sensitivity in type 2 diabetes

The aim of the present study was to evaluate the acute effect of ethanol on insulin sensitivity, and glucose, insulin, free fatty acid (FFA), and triacylglycerol responses in ten patients with non-insulin-dependent (type 2) diabetes. In the test study an oral dose of 0.66 g ethanol/kg followed by continuous intravenous infusion of 0.1 g ethanol/kg per h was given to maintain a constant ethanol level in the blood. In the control study identical volumes of oral water and intravenous saline (9 g NaCl/l) were given. After 90 min insulin sensitivity was determined by the hyperinsulinaemic, euglycaemic clamp technique. Ethanol caused no change in blood glucose or insulin concentrations. The FFA level was suppressed by ethanol while the triacylglycerol level was unaffected. The insulin sensitivity was not affected by ethanol. No major acute effect of ethanol on the glycaemic control in fasting type 2 diabetic patients was found in comparison with what is seen in healthy people. The present study, along with the sparse literature, indicates that the ability of ethanol to induce hypoglycaemia is attenuated or absent in diet-treated type 2 diabetes. Furthermore, we found no change in insulin sensitivity. Consequently, the risk of acute ethanol-induced aberrations in carbohydrate metabolism in diet-treated type 2 diabetes seems to be less than previously expected, when alcohol is not taken as a part of a meal.

Short-term effects of alcohol consumption on appetite and energy intake

The relationship between alcohol intake and obesity remains uncertain. Evidence suggesting that alcohol-derived energy may be unregulated points to an inability to maintain appetite, energy balance and, hence, body weight when alcohol is introduced to the diet. This study investigated the short-term effects of alcohol on hunger and energy intake in 20 lean women. On 4 occasions, subjects were given a randomised preload drink ('alcohol', 'no alcohol', 'carbohydrate', 'water') followed by visual analogue scales (VAS) rating hunger and an ad lib test meal. There was no difference in hunger ratings (p > 0.05) nor in the amount of energy consumed during the test meal (F = 1.66, p > 0.05) following any of the 4 preloads. Consumption of the 2 high energy preload drinks ('alcohol', 0.91 MJ; 'CHO', 0.72 MJ) did not result in a compensatory decrease in the amount of energy subsequently eaten (ad lib intake: 'alcohol' = 2.62 MJ, 0.32 SEM; 'no alcohol' = 2.98 MJ, 0.28 SEM; 'CHO' = 2.93 MJ, 0.21 SEM; 'water' = 2.82 MJ, 0.25 SEM), suggesting either no physiological recognition or no regulation of energy consumed within a drink in quantities of less than 1 MJ. The addition of either alcoholic or CHO-containing carbonated beverages into the diet will result, in the short-term, to an overall increase in energy intake.

Effect of alcohol on glucose, insulin, free fatty acid and triacylglycerol responses to a light meal in non-insulin-dependent diabetic subjects

Alcohol accounts for 4-6% of the average energy intake in most Western countries. Alcohol-induced hypoglycaemia is a well-known and feared complication in insulin-dependent diabetic subjects, but little attention has been paid to the impact of alcohol on carbohydrate metabolism in non-insulin-dependent diabetes. The aim of the present study was to investigate in non-insulin-dependent diabetic subjects the acute metabolic effects of a moderate amount of alcohol taken with a light meal, conditions chosen to mimic an everyday situation. The patients received 500 ml non-alcoholic beer with an alcohol content (ml/l) of 0 (treatment A) and 54 (treatment B) together with a light meal, implying identity of the contents of ingredients except for alcohol. We found similar serum glucose, insulin, free fatty acid and triacylglycerol responses irrespective of addition of a modern amount of alcohol. In conclusion, a moderate amount of alcohol can be taken with a meal without eliciting hypoglycaemia in non-insulin-dependent diabetic subjects.

The incidence of ethanol-induced hypoglycemia

The purpose of the study was to determine the incidence of ethanol-induced hypoglycemia. All nondiabetic patients who had blood alcohol levels above 0.10% and a random serum chemistry drawn (including glucose) were included. Over a 6-month study period, 378 patients were included in the study. Fifteen patients (4%) presented with hypoglycemia (glucose less than 67 mg%). Of these, four (1%) were profoundly hypoglycemic (glucose less than 50 mg%). Two hundred and fifty three patients (67%) patients were normoglycemic (glucose 67-106 mg%) and 110 patients (29%) were hyperglycemic (glucose greater than 106 mg%). Nonfasting glucose measurements from a control group of 96 nondiabetic, nonintoxicated patients were compared with those of the study group. Two patients (2%) presented with hypoglycemia and none (0%) presented with profound hypoglycemia. Forty-five patients (47%) presented with normoglycemia, and 49 (51%) with hyperglycemia. There were no statistically significant differences found in the hypoglycemia rate between the intoxicated patients and nonintoxicated control population (odds ratio of 0.75; P greater than .05). Four of 378 intoxicated patients (1%) had profound hypoglycemia (less than 50 mg/dL) compared with none (0%) of the 96 nonintoxicated patients. Intoxicated patients had a statistically significant lower rate of hyperglycemia in comparison with the nonintoxicated control group (29% versus 51%; P less than .0001). Age, sex, race, ethanol level, and serum electrolyte measurement had no predictive value for hypoglycemia in intoxicated patients. The anion gap was consistently elevated in hypoglycemic patients in comparison with normoglycemic patients (P less than .05). Hypoglycemia appears to occur as frequently in an ethanol-intoxicated population as in a population without elevated ethanol levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The syndrome of alcoholic ketoacidosis

PURPOSE

To further elucidate the clinical spectrum of alcoholic ketoacidosis (AKA).

PATIENTS AND METHODS

A case series of 74 patients with AKA defined as a wide anion gap metabolic acidosis unexplained by any other disorder or toxin, including any patient with a history of chronic alcohol abuse. The setting was the Medical Emergency Department at Grady Memorial Hospital in Atlanta, Georgia, a university-affiliated inner-city hospital.

RESULTS

AKA is a common disorder in the emergency department, more common than previously thought. The acid-base abnormalities are more diverse than just a wide-gap metabolic acidosis and often include a concomitant metabolic alkalosis, hyperchloremic acidosis, or respiratory alkalosis. Lactic acidosis is also common. Semiquantitative serum acetoacetate levels were positive in 96% of patients. Elevated blood alcohol levels were present in two thirds of patients in whom alcohol levels were determined, and levels consistent with intoxication were seen in 40% of these patients. Electrolyte disorders including hyponatremia, hypokalemia, hypophosphatemia, hyperglycemia, hypocalcemia, and hypomagnesemia were common on presentation. The most common symptoms were nausea, vomiting, and abdominal pain. The most common physical findings were tachycardia, tachypnea, and abdominal tenderness. Altered mental status, fever, hypothermia, or other abnormal findings were uncommon and reflected other underlying processes.

CONCLUSIONS

AKA is a common disorder in chronic malnourished alcoholic persons. The acid-base abnormalities reflect not only the ketoacidosis, but also associated extracellular fluid volume depletion, alcohol withdrawal, pain, sepsis, or severe liver disease. Although the pathophysiology is complex, the syndrome is rapidly reversible and has a low mortality.

Effects of ethanol on glucose turnover in pregnant rats

Glucose turnover was measured in term pregnant rats fed ethanol (30% of caloric intake) throughout gestation. Ethanol ingestion significantly reduced maternal weight gain and term fetal body weight when compared to pair-fed or ad libitum-fed controls. At term the blood glucose level and 6-3H-glucose turnover were reduced when compared to either control group. The rate of gluconeogenic recycling, indicated by the difference between 6-3H and 6-14C-glucose turnover determinations, was reduced by ethanol ingestion to half that of the control groups. Glucose turnover correlated with both conceptus weight and blood glucose level. Impaired maternal glucose homeostasis, including a reduced gluconeogenic response to the metabolic demands of late pregnancy, may thus contribute to the effects of ethanol on intrauterine growth.

Effect of alcohol on glucose tolerance in normal and noninsulin-dependent diabetic subjects

Oral glucose tolerance tests were conducted in 10 noninsulin-dependent diabetic and 14 healthy control subjects with a 75-g glucose load. The tests were repeated 1 week later with 43 g of ethanol mixed with the glucose. Blood samples were analyzed for ethanol, glucose, insulin, C-peptide, and glucagon levels. The blood ethanol peak was nearly equal in diabetic and control subjects (mean +/- SEM values of 55 +/- 8 and 48 +/- 6 mg/dl 45 min after ethanol ingestion). Ethanol did not affect glucose tolerance in either of the study groups. Mean +/- SEM values of the sum of the increment above the baseline glucose level were 659 +/- 48 vs. 675 +/- 76 mg/dl with or without ethanol in diabetics and 227 +/- 35 vs. 244 +/- 36 mg/dl in control subjects. The plasma insulin and C-peptide responses to glucose were delayed in diabetic patients compared to controls but were not affected by ethanol. In vitro, ethanol, at a concentration of 100 mg/dl or greater, significantly decreased insulin binding to erythrocytes in a dose-related manner. Scatchard analysis of competitive insulin binding to erythrocytes indicated that ethanol reduced insulin binding affinity (1.6 +/- 0.5 vs. 4.2 +/- 0.8 x 10(8)/M), but not binding capacity (4.5 +/- 2.4 vs. 4.4 +/- 1.7 nM, with and without ethanol, respectively).

Metabolic response to starvation at late gestation in chronically ethanol-treated and pair-fed undernourished rats

To study the role of undernourishment in the negative effects of ethanol during pregnancy and to determine whether maternal ethanol intake modifies metabolic response to starvation at late gestation, female rats receiving ethanol in their drinking water before and during pregnancy (ethanol group) were compared with animals that received the same amount of solid diet as the ethanol group rats (pair-fed group) and with normal rats fed ad libitum (control group). All animals were killed on the 21st day of gestation, either in the fed state or after 24-hours fasting. The body weight of ethanol rats was lower than that of controls but higher than that of pair-fed rats. When compared with controls, ethanol and pair-fed rats had reduced fetal body weights, whereas fetal body length was reduced only in the former. In the fed state, blood glucose concentration was lower in the ethanol and pair-fed rats and fetuses than in controls. Twenty-four-hour starvation caused a reduction in this parameter only in control and ethanol mothers. In the fed state, maternal liver glycogen concentration was lower in ethanol and higher in pair-fed mothers than in controls. Blood beta-hydroxybutyrate levels were higher in ethanol-treated mothers than in the others, and 24-hour starvation increased this parameter in ethanol and control rats to a greater extent than in the pair-fed ones. Liver triacylglyceride concentration was higher in ethanol-treated mothers than in the other two groups, and starvation caused this concentration to increase in ethanol and control groups but not in the pair-fed group.(ABSTRACT TRUNCATED AT 250 WORDS)

Limitation in glucose penetration from the liver into blood and other metabolic symptoms of ethanol withdrawal in rats

Studies were undertaken to determine whether the distribution of glycolytic intermediates between the blood and liver in rats would be changed upon ethanol consumption and after its withdrawal. More drastic impairment of energy metabolism appeared to occur after ethanol withdrawal than upon chronic ethanol ingestion. The major metabolic manifestations of withdrawal were severe hypoglycemia, hyperlactatemia and dramatic hypopyruvatemia. The liver/blood gradient of glucose attained a value of 4.2 after ethanol withdrawal, suggesting that glucose penetration from the liver into circulation became limited. Besides, glycogen was accumulated in the liver of withdrawn animals despite the severe hypoglycemia.

Role of alcohol in clinical nephrology

Different nephrological derangements are observed in severe alcoholics. Until now the direct toxicity of ethanol is only shown in the fetal alcohol syndrome with various malformations of the genitourinary tract. In the adult the kidney is often involved in the development, maintenance and counterregulation of complex electrolyte disturbances like phosphate and potassium hypoglycemia etc. The alcohol associated retention of urate, induced by hyperlactatemia and/or increased beta-hydroxybutyrate concentration is only rarely complicated by urate nephropathy. Alcohol intoxication (acute and chronic) predisposes to rhabdomyolysis with the risk of acute renal failure. There are some hints that chronic alcoholism with myopathy increases the vulnerability of the kidney for further toxic agents. In rats glycerol induced renal failure is enhanced by alcohol pretreatment. Finally, regular alcohol consumption raises the blood pressure, which per se is a risk factor for renal damage.

Similar metabolic response to acute ethanol intake in pregnant and non-pregnant rats either fed or fasted

Plasma ethanol concentration 3 hr after its oral administration (3 g/kg body wt) did not differ in 20 day pregnant rats with virgin controls, and in both groups values were higher when studied after 24 hr fasted than when fed. In fed animals, blood glucose and liver glycogen concentrations were lower in pregnant than in virgin rats, whereas ethanol intake in both groups enhanced blood glucose levels, it reduced liver glycogen content only in virgins. In fetuses, maternal ethanol intake enhanced blood glucose levels. In fasted animals, ethanol intake decreased blood glucose levels in pregnant and virgin animals but did not affect these levels in fetuses. Ethanol intake enhanced beta-hydroxybutyrate/acetoacetate ratio similarly in blood of pregnant and virgin rats when either fed or fasted, and it produced the same change in fetuses from fasted mothers. Results indicate that the metabolic response to acute ethanol does not differ between pregnant and non-pregnant animals, and it is proposed that fetuses passively follow the metabolic changes occurring in their mothers after receiving ethanol.

The 8-hour metabolic profile after drinking ethanol

The acute metabolic changes after drinking ethanol have been studied in 11 fasting, healthy, nonobese, medical students, 6 of whom consumed 40 g ethanol diluted with 750 ml of a sugar-free soft drink over 1 h. The other 5 drank the same volume of soft drink alone. Blood levels of ethanol, glucose, immunoreactive insulin and growth hormone were measured over the ensuing 8 h, as well as the plasma concentrations of prolactin, cortisol and triiodothyronine. After ingesting ethanol, the mean plasma glucose concentration declined, but not to hypoglycemic levels (the nadir was 3.9 mmol/l at 6 h), insulin levels fell gradually and the mean growth hormone concentration showed a modest late rise. Other hormones did not change significantly. We conclude that, in the particular setting examined, the oral administration of ethanol does not cause hypoglycemia or other adverse effects on carbohydrate metabolism.

Alcoholic epilepsy: review of a series and proposed classification and etiopathogenesis

A review of the convulsive seizures of 153 alcoholics is followed by a proposed classification with the aim of defining more precisely the pattern of so-called alcoholic epilepsy and distinguishing it from the other alcohol-related seizures (due to sudden changes in alcohol intake: convulsive inebriation or alcohol withdrawal seizures) and seizures in which alcohol is only one of the pathogenetic factors. Particular attention is devoted to an analysis and comparison of alcohol withdrawal seizures and alcoholic epilepsy, which are a source of nosological confusion. The results of oral glucose tolerance tests suggest an etiopathogenesis for alcoholic epilepsy based on the carbohydrate metabolism.

Release of glucagon in male alcoholics with vagal neuropathy

There is evidence supporting involvement of the parasympathetic nervous system in the control of glucagon secretion. We have investigated the possible role of vagal neuropathy in alcoholics as a cause of alcoholic hypoglycemia. Slow infusions of insulin (2.4 U/hr) were carried out in ten male alcoholics, four with and six without evidence of vagal neuropathy, and in six male controls. The fall in blood glucose levels and the rise in serum glucagon levels in the alcoholics with or without vagal neuropathy were not significantly different from controls. We conclude that vagal neuropathy in alcoholics has no effect on the glucagon response to hypoglycemia.

Metabolic acidosis in the alcoholic: a pathophysiologic approach

The purpose of this paper is to review the acid-base abnormalities in patients presenting with metabolic acidosis due to acute ethanol ingestion and to review the theoretical constraints on ethanol metabolism in the liver. Alcohol-induced acidosis is a mixed acid-base disturbance. Metabolic acidosis is due to lactic acidosis, ketoacidosis and acetic acidosis but the degree of each varies from patient to patient. Metabolic alkalosis is frequently present due to ethanol-induced vomiting. However, it could be overlooked because of an indirect loss of sodium bicarbonate (as sodium B-hydroxybutyrate in the urine). Nevertheless, the accompanying reduction in ECF volume may play an important role in the pathogenesis of alcoholic acidosis because it could lead to a relative insulin deficiency. Treatment of alcohol acidosis should include sodium, chloride, potassium, phosphorus, magnesium and thiamine replacements along with attention to concomitant clinical problems. Unless hypoglycemia is present, glucose need not be given immediately. We feel that insulin should be withheld unless life-threatening acidemia is present or expected. Lastly, alcohol need not be detected on admission to make the diagnosis of this metabolic disturbance. However, when present, it could contribute directly to the lactic, acetic and B-hydroxybutyric acidoses. With respect to the theoretical constraints on ethanol metabolism, it appears that "overproduction" of NADH in the liver is best averted by converting ethanol to B-hydroxybutyric acid.

The alcoholic patient and surgical stress

In order to find out how the response to operative trauma is influenced by chronic alcohol consumption, 53 patients (28 alcoholics and 25 non-alcoholics) were investigated. The chronic alcoholic was defined as a person having a regular, daily alcohol consumption of over 70 g pure alcohol for at least 3 years. The mean annual consumption in the patients studied was 52 litres pure alcohol (143 ml/day). The investigation was also designed to determine whether the pre-operative infusion of alcohol could prevent the withdrawal syndrome and in that way alter the stress response. The results clearly showed a diminished adrenocortical response to surgical stress in alcoholic patients. While it was possible to suppress some catecholamine-mediated withdrawal symptoms by pre-operative alcohol infusion this did not influence the stress response in any way. It is concluded that complications under anaesthesia and in convalescence in alcoholic patients are not only the consequence of the withdrawal but rather of the general toxic effects of alcohol especially on the endocrine and metabolic functions.

A realistic method of health hazard appraisal for the occupational health nurse

The author assumed responsibility or an ongoing factory health maintenance program which consisted primarily of periodic blood and urine sampling and analysis. To supplement the limited information obtained from these laboratory analyses, the author began gathering personal health history information from each worker through a standardized questionnaire. It was during the review of one completed questionnaires that one need for a description of the workforce as a group became evident. To do this, a new approach — one different from the traditional nursing approach of individualized assessment — was tried.

An epidemiological study was deigned which yielded information on the demographic profile of the workforce, as well as the relationships between three agents of exposure (chemicals, ethanol, and cigarettes) and laboratory parameters.

The procurement of this data proved to be of value in several ways: One identification of high risk groups or particular diseases, the assessment of existing and future health problems, and in the planning for the health care of the group.

The increased value of the data obtained by utilization of the epidemiological method allows the occupational health nurse in the workplace setting to improve the delivery of health services to those under her care.

Experimental studies on the "cow's urine mixture"

Samples of the "Cow's Urine Mixture" (a traditional remedy for convulsions) administered intraperitoneally to fasting grey rabbits were found to produce significant depression of their plasma glucose. A similar effect on the plasma glucose was produced by a sample of Cow's Urine Mixture given by the nasogastric route. These findings confirm that the mixture has a significant hypoglycaemic effect when given both parenterally and enterally, the latter being the usual mode of administration of this concoction. The probable nature of the hypoglycaemic agents contained in the mixture is discussed.

Ethanol-insulin interrelationships in the rat studied in vitro and in vivo: evidence for direct ethanol inhibition of biphasic glucose-induced insulin secretion

The effect of ethanol (ETOH) on glucose-stimulated insulin secretion was studied using: (1) an in vitro isolated pancreas perfusion system, and (2) an in vivo preparation utilizing unrestrained, unanesthetized rats with indwelling jugular and aortic catheters. ETOH exposure in vitro resulted in a decrease in glucose-stimulated insulin secretion from the perfused rat pancreas. Second phase secretion (min 30-60) was inhibited at low ETOH exposure (100 mg/dl) and both first (min 2-8) and second phase secretion were inhibited at higher ETOH levels (1000 mg/dl). This indicates that second phase secretion of insulin from the pancreas is more sensitive to the acute effects of ETOH than is first phase secretion. ETOH preinfusion of 4 hr in vivo resulted in an approximate 20 mg/dl decrease in plasma glucose concentrations with little or no alteration in plasma insulin levels. One hour ETOH preinfusion produced a modest 8 mg/dl fall in plasma glucose. Intravenous glucose tolerance tests following low level ETOH infusion of 4 hr resulted in an enhancement in the insulin response with no change in glucose removal. This enhancement was not observed at higher ETOH levels or after high-level, short (1 hr) ETOH preinfusion. The data suggest that stimulus-induced insulin secretion may be enhanced by an ETOH metabolite if the ETOH exposure is prolonged and at a low level. Higher ETOH concentration appears to directly block this enhancement. Due to response similarities the rat model may be of considerable value to study the effects of ETOH on stimulus-induced insulin secretion in human subjects.

The use of isotope turnover techniques in the study of carbohydrate metabolism in man

It now appears that the bulk of methodological, analytical and interpretative problems associated with the use of isotope turnover techniques for the study of carbohydrate metabolism in man are resolved. As illustrated by a number of examples of the use of these techniques for the assessment of carbohydrate metabolism they seem, to the author, to have been more critically useful in the resolution of questions of (a) mechanism of hormone and drug action and (b) of interactions between metabolites, than they have been in defining pathological states, although the volume of information that is being accumulated is sure to prove useful for future research. Although it is this author's opinion that the employment of the radioactive isotopes at the low levels allowed by todays technology does not impose an unreasonable risk to the research subject, the promise of increased sensitivity for the detection of stable isotopes and the promise of their increased availability in a wide variety of compounds are factors that are sure to provide impetus for the wider use of these most valuable techniques in medical research.

Diabetic emergencies: hypoglycemia and ketoacidosis

Because hypoglycemia may be rapidly fatal it must be diagnosed and treated early. Ketoacidosis may be difficult to differentiate from hypoglycemia. The diagnosis, treatment and causes of both diabetic emergencies are described. Once rehydration is instituted, further management can be directed using appropriate laboratory and bedside studies that allow stabilization with a high degree of control.

Reactive hypoglycemia

The hypoglycemoses include a large category of distinctly unique entities. Guidelines for a clinical, physiological approach to these disorders is presented. Within this diagnostic spectrum of hypoglycemia lies the reactive hypoglycemic disorders that are characterized by their postprandial onset, adrenergic mediated symptoms, and relatively benign causes. The spectrum of reactive hypoglycemia includes early alimentary-reactive hypoglycemia, late diabetic-reactive hypoglycemia, hormonal deficiency states, and idiopathic hypoglycemia. A new postprandial hypoglycemic disorder, fructose 1-6 diphosphatase, can be added to this list. The frequent sampling of blood-glucose values in the postprandial state will frequently lead to the finding of a biochemically low blood-glucose value of below 50 ml/100 ml, and these individuals show no hypothalamic-pituitary-adrenal stress to the low blood sugar and do not manifest adrenergic symptoms. Their low blood-glucose value simply reflects the transition in intermediary metabolism between the fed and fasting state and provides a biochemical marker of this event. We refer to this asymptomatic biochemical event as transitional low blood-glucose state. It has no clinical implication and may frequently be confused with the bona fide reactive hypoglycemic disorders. Using a symptomatic, counter-regulatory model to define hypoglycemia as a bona fide disorder, findings are presented in patients with the varying types of reactive hypoglycemia, and their results are compared to normal controls and to a weight-matched and disease patient controls. Abnormalities in insulin secretion are discussed as relating to the pathophysiology causal in the hypoglycemia. An approach to therapy is presented based upon the classification of the patient as to the type of hypoglycemia and their abnormalities in insulin secretion.

Control of the redox state of the nicotinamide-adenine dinucleotide couple in rat liver cytoplasm

1. A study has been made of the ability of rat liver in vivo to maintain equilibrium in the combined glyceraldehyde 3-phosphate dehydrogenase, 3-phosphoglycerate kinase and lactate dehydrogenase reactions, i.e. in the system: [Formula: see text] Attempts were made to upset equilibrium. The [lactate]/[pyruvate] ratio was rapidly changed by injection of ethanol or crotyl alcohol, and the value of [ATP]/[ADP][HPO(4) (2-)] was rapidly changed by injection of ethionine or carbonyl cyanide p-trifluoromethoxy-phenylhydrazone. 2. The concentrations of the metabolites occurring in the above equation were measured in freeze-clamped liver. 3. Although the injected agents caused large changes in the concentrations of the individual components, near-equilibrium in the system was maintained, as indicated by the fact that the value of [ATP]/[ADP][HPO(4) (2-)], referred to as the phosphorylation state of the adenine nucleotides, measured directly agreed with the value calculated for equilibrium conditions from the above equation. 4. The results are discussed and taken to confirm that the order of magnitude of the value of the redox state of the cytoplasmic NAD couple in rat liver is controlled by the phosphorylation state of the adenine nucleotide system.

Glucose-lactate interrelationships: effect of ethanol

The effect of ethanol on the interrelationship of lactate and glucose metabolism was investigated in eight human volunteers. Lactate and glucose kinetics and intervconversion rates were determined by the sequential administration of L-(+) lactate-U-(14)C and glucose-1-(14)C over an 8 hr period. After a 12 hr fast, the glucose turnover and recycling rates were 94.0 +/-3.8 (SEM) and 13.7 +/-1.1 mg/kg per hr, respectively. Approximately 50% of the glucose turnover or 40.7 +/-2.1 mg/kg per hr was converted to lactate, accounting for 50% of the lactate turnover rate. Lactate turnover and lactate conversion to glucose were 81.8 +/-6.2 and 16.7 +/-1.1 mg/kg per hr, respectively. Approximately 20% of the glucose turnover was derived from lactate under these conditions. During the administration of ethanol, the blood lactate concentration doubled and the lactate turnover rate declined slightly. Lactate conversion to glucose was markedly inhibited, decreasing from 16 to 5 mg/kg per hr, and the per cent of the glucose turnover derived from lactate decreased from 18 to 6. Despite the marked inhibition of lactate conversion to glucose, neither the blood glucose concentration nor the glucose turnover rate changed. Both glucose recycling and glucose conversion to lactate were decreased, indicating that ethanol inhibited peripheral glucose utilization. There was no difference in the degree of inhibition of lactate incorporation into glucose produced by ethanol when nonfasted subjects were compared with two subjects who had fasted for 48-72 hr despite the presence of hypoglycemia in the latter. These results indicate that starvation is not a prerequisite for ethanol inhibition of gluconeogenesis from lactate in humans but is necessary for the development of hypoglycemia. Inhibition of lactate incorporation into glucose in nonfasted subjects is probably masked by a concomitant increase in glycogenolysis which prevents hypoglycemia. Ethanol decreases glucose conversion to lactate as well as lactate conversion to glucose, thus inhibiting the Cori cycle.