Serum tolbutamide and chlorpropamide concentrations in patients with diabetes mellitus

A selective and sensitive gas chromatographic technique was used to measure the steady-state serum concentrations of tolbutamide and chlorpropamide in 97 patients with maturity-onset diabetes mellitus who had been taking these drugs (37 tolbutamide, 60 chlorpropamide) for at least a year. No other antidiabetic agents had been given. The serum tolbutamide concentrations varied widely between the patients (from close to zero to 370 μmol/l (100 μg/ml)), yet the variation in dosage was only sixfold (0·5-3·9 g daily). The serum chlorpropamide concentrations varied even more widely (from close to zero to 882 μmol/l (244 μg/ml)), though the dosage variation was fourfold (125-500 mg daily). There was no systematic relation between dosage and serum concentrations of the drugs.Only 2 (5·4%) of the tolbutamide-treated patients and 10 (16·7%) of the chlorpropamide-treated patients had normal fasting blood glucose concentrations (below 5·5 mmol/l (99 mg/100 ml)), and fewer than half had values below 8·0 mmol/l (144 mg/100 ml). In most cases, therefore, the treatment was insufficient.There was no significant difference in mean fasting blood glucose concentrations between the two treatment groups. The mean steady-state concentration of chlorpropamide, however, was significantly higher than that of tolbutamide. Thus, contrary to common belief, the intrinsic activity of chlorpropamide is apparently not greater than that of tolbutamide. The alleged greater potency of chlorpropamide seems to be related wholly to kinetic differences, such as the less extensive metabolic degradation and slower elimination of the drug.We conclude that treatment with sulphonylureas in conventional dosage is far from optimal and that monitoring the concentrations of these drugs in the blood may help to improve their efficacy.     

Carbohydrate metabolism in pregnancy. Part II. Relation between maternal glucose tolerance and glucose metabolism in the newborn.

The objective of clinical management of the pregnant diabetic woman is to prevent the serious adverse effects of an abnormal glucose environment on the fetus. Neonatal glucose assimilation and insulin release over the first two hours of life were correlated with various indices of maternal carbohydrate metabolism in the third trimester. Of the 31 mothers studied 21 were defined as normal and 10 as having chemical diabetes. Neontal glucose assimilation during the first two hours of life correlated strongly with functions of both maternal glucose tolerance and mean diurnal glucose level, the strongest correlation being with the area under the three-hour oral glucose tolerance curve (P less than 0.001), Two-hour neonatal plasma glucose values of under 1.7 mmol/1 (30 mg/100 ml) were found only in the newborn of women whose glucose tolerance area measured over 41.6 area units (750 traditional units); thus, even in the borderline diabetic range glucose tolerance testing during the last trimester of pregnancy may be valuable in predicting likelihood of neonatal hypoglycaemia. The findings also shed light on the possible sensitizing role of mild maternal hyperglycaemia on fetal insulin production and secretion.     

Reference values for 75 g oral glucose tolerance test in pregnancy

A 75 g oral glucose tolerance test was performed in 212 pregnant women with no predisposing factors suggesting glucose intolerance to establish the normal pattern of glucose metabolism in pregnancy. Reference values for the test were established for the middle of pregnancy (14-20 weeks, n=43) and late pregnancy (28-37 weeks, n=168). One woman was excluded because she had diabetes that required treatment with insulin. There were statistically significant differences between the two groups for samples taken both one and two hours after the glucose load. Reference ranges for the interpretation of the glucose tolerance test in pregnancy should therefore take account of the period of gestation.Arbitrary upper limits of normal (represented by the 97·5 centile) two hours after a 75 g oral glucose load are proposed at 7·5 and 9·6 mmol/l for the second and third trimesters, respectively.     

Carbohydrate metabolism in pregnancy. Part I. Diurnal plasma glucose profile in normal and diabetic women.

Diurnal plasma glucose profiles and oral glucose tolerance during pregnancy were studied in normal women, chemical diabetics, and insulin-requiring diabetics. In normal women the mean diurnal plasma glucose rose by only 0.22 mmol/1 (4 mg/100 m1) during pregnancy. Mild chemical diabetes resulted in an increase in both the mean diurnal glucose concentration and the fluctuation of plasma glucose levels during the day. Fluctuation in glucose concentration in insulin-dependent diabetics was about three times that found in non-diabetic women of similar gestation, with relative hyperglycaemia during the day and hypoglycaemia at night. In non-diabetic women and those with chemical diabetes the mean dirunal glucose correlated closely with the total area under the three-hour oral glucose tolerance curve and significantly, but less closely, with the two-hour glucose tolerance test value.     

Maternal exposure to dexamethasone or cortisol in early pregnancy differentially alters insulin secretion and glucose homeostasis in adult male sheep offspring

An adverse intrauterine environment increases the risk of developing various adult-onset diseases, whose nature varies with the timing of exposure. Maternal undernutrition in humans can increase adiposity, and the risk of coronary heart disease and impaired glucose tolerance in adult life, which may be partly mediated by maternal or fetal endocrine stress responses. In sheep, dexamethasone in early pregnancy impairs cardiovascular function, but not glucose homeostasis in adult female offspring. However, male offspring are often more susceptible to early life "programming". Pregnant sheep were infused intravenously with saline (0.19 ml/h), dexamethasone (0.48 mg/h), or cortisol (5 mg/h), for 2 days from 26 to 28 days of gestation. In male offspring, size at birth and postnatal growth were measured, and glucose tolerance [intravenous glucose tolerance test (IVGTT)], insulin secretion, and insulin sensitivity of glucose, alpha-amino nitrogen, and free fatty acid metabolism were assessed at 4 yr of age. We show that cortisol, but not dexamethasone, treatment of mothers causes fasting hyperglycemia in adult male offspring. Maternal cortisol induced a second-phase hyperinsulinemia during IVGTT, whereas maternal dexamethasone induced a first-phase hyperinsulinemia. Dexamethasone improved glucose tolerance, while cortisol had no impact, and neither affected insulin sensitivity. This suggests that maternal glucocorticoid exposure in early pregnancy alters glucose homeostasis and induces hyperinsulinemia in adult male offspring, but in a glucocorticoid-specific manner. These consequences of glucocorticoid exposure in early pregnancy may lead to pancreatic exhaustion and diabetes longer term and are consistent with stress during early pregnancy contributing to such outcomes in humans.     

Host Remodeling of the Gut Microbiome and Metabolic Changes during Pregnancy

Many of the immune and metabolic changes occurring during normal pregnancy also describe metabolic syndrome. Gut microbiota can cause symptoms of metabolic syndrome in nonpregnant hosts. Here, to explore their role in pregnancy, we characterized fecal bacteria of 91 pregnant women of varying prepregnancy BMIs and gestational diabetes status and their infants. Similarities between infant-mother microbiotas increased with children's age, and the infant microbiota was unaffected by mother's health status. Gut microbiota changed dramatically from first (T1) to third (T3) trimesters, with vast expansion of diversity between mothers, an overall increase in Proteobacteria and Actinobacteria, and reduced richness. T3 stool showed strongest signs of inflammation and energy loss; however, microbiome gene repertoires were constant between trimesters. When transferred to germ-free mice, T3 microbiota induced greater adiposity and insulin insensitivity compared to T1. Our findings indicate that host-microbial interactions that impact host metabolism can occur and may be beneficial in pregnancy.     

Toward improving postgraduate medical education.

Twenty-two patients receiving 5 per cent glucose solution intravenously during an acute illness were studied for evidence of hyperglycemia. Those in whom blood sugar rose above 100 mg per 100 ml (Folin-Wu) during intravenous therapy subsequently had impairment of carbohydrate tolerance as measured by oral glucose tolerance tests. The data collected suggested that blood sugar of 100 mg per 100 ml (Folin-Wu) or more developing in such a setting is a clue to the presence of diabetes mellitus.     

Pregnancy in diabetic women: outcome with a program aimed at normoglycemia before meals.

A program designed to achieve normal plasma glucose concentrations before meals was tested in 83 insulin-dependent diabetic women during 110 pregnancies. The women rigidly controlled their carbohydrate intake but not their total energy intake, and twice daily they injected a combination of short-acting (Toronto) and intermediate-acting (NPH or Lente) insulin. Obstetric care was highly individualized and was aimed at avoiding or minimizing the impact of complications, such as hypertension, on the fetus and ensuring fetal lung maturity before delivery. The mean plasma glucose levels before meals (+/- standard error of the mean) were 136 +/- 9, 117 +/- 5 and 101 +/- 2 mg/dl during the first, second and third trimesters respectively. Obstetric complications included hypertensive disease of pregnancy (in 30.0%) and hydramnios (in 16.4%). The mean gestational age (+/- standard deviation [SD]) was 38.1 +/- 1.8 weeks, the cesarean section rate 45.4% and the mean stay in hospital for diabetes control before delivery (+/- SD) 15.7 +/- 9.6 days. The perinatal mortality rate was 0.9%. Neonatal problems included congenital anomalies in 3.6%, somatomegaly in 24.6%, hypoglycemia in 26.5%, hypocalcemia in 17.3% and hyperbilirubinemia in 39.4%. There were nine cases (8.2%) of the respiratory distress syndrome, four (3.6%) of which were severe. These findings lend support to the importance of a policy aimed at achieving normoglycemia and fetal lung maturity before delivery, goals that are attainable without lengthy antenatal hospitalization.     

The influence of mildronate on peripheral neuropathy and some characteristics of glucose and lipid metabolism in rats with the streptozotocin model of diabetes mellitus

Rats with the streptozotocin (STZ) model of diabetes mellitus were treated with mildronate (100 mg/kg daily, per os or intraperitoneally) for 6 weeks. Body weight, blood glucose, triglycerides, ketone body concentrations, percent of glycated hemoglobin (HbA1c%), glucose tolerance, and the development of neuropathic pain were monitored throughout the whole experiment. The mildronate treatment completely prevented the development of the diabetic neuropathy from the first week up to the end of experiment. In the group of diabetic animals treated with mildronate a significant decrease of blood glucose was observed on the fourth week of the treatment, the level of triglycerides decreased from the third to sixth weeks. Mildronate also decreased accumulation of glycated hemoglobin on the sixth week and improved glucose tolerance compared with untreated animals. The data obtained confirm applicability of mildronate for therapy of diabetes mellitus and its complications.     

Short-Term Estrogen Replacement Effects on Insulin Sensitivity and Glucose Tolerance in At-Risk Cats for Feline Diabetes Mellitus

Male domestic cats that are neutered and overweight are at an increased risk for developing a type-2-like diabetes mellitus. Beneficial effects of 17β-estradiol (E2) on glucose homeostasis may be lost with neutering and thereby account for increased diabetes risk. To evaluate this, adult male neutered overweight cats (n=6) were given daily E2 (1.0 μg/kg) or vehicle (Vh; ethanol, 1.0μL/kg) in a single crossover trial of 14-day periods with a 7-day washout. The E2 and Vh were voluntarily ingested on food. The E2 dosage was determined in a pre-trial to significantly and transiently reduce food intake with no measurable change in plasma E2 concentration. During treatments, physical activity was assessed with collar-mounted accelerometers on days 9-11, and tests of intravenous insulin tolerance and intravenous glucose tolerance were conducted on days 13 and 14, respectively. Over the 14 days, E2 compared to Vh treatment reduced (p=0.03) food intake (- 22%) but not enough to significantly reduce body weight; activity counts were not significantly changed. With E2 compared to Vh treatment, the late-phase plasma insulin response of the glucose tolerance test was less (p=0.03) by 31%, while glucose tolerance and insulin sensitivity indexes were not significantly changed. The results indicate that oral E2 at a dosage that moderately affects food intake may reduce insulin requirement for achieving glucose homeostasis in neutered male cats. Further investigation is needed to identify the mechanism underlying the E2 effect.     

Is gestational diabetes an acquired condition?

Intrvenous injection of 30 mg of streptozotocin per kg body weight induces a mild diabetes in pregnant rats (first generation); the non-fasting blood glucose is increased and the percentage of endocrine tissue and also the percentage of granulated beta cells do not increase. The fetuses of these mildly diabetic pregnant rats have an increased percentage of pancreatic endocrine tissue and there is beta-cell degranulation. The modifications in the endocrine pancreas during intrauterine life causes persistent changes in later adult life (second generation), which are not perceptible in basal conditions, but become apparent in situations stressing the beta-cell activity, such as an intravenous glucose load or pregnancy. During pregnancy in the second generation rats an increased non-fasting blood glucose and no adaptation of the beta cells is seen. This inadequate adaptation to pregnancy causes changes in the fetal endocrine pancreas of the fetuses of the third generation. From these experiments it may be concluded that gestational diabetes is an acquired condition.     

Selenium and malondialdehyde content and glutathione peroxidase activity in maternal and umbilical cord blood and amniotic fluid

Placenta tissue may be a major source of lipid peroxidation products in pregnancy. It was proven that placental peroxidation activity increases with gestation. Selenium (Se), as an essential constituent of glutathione peroxidase (GSH-Px), takes part in the reduction of hydrogen peroxides and lipid peroxides. Malondialdehyde (MDA) is a major breakdown product split off from lipid peroxides. In this study, Se and MDA content and GSH-Px activity were measured in blood and plasma taken from 20 apparently healthy nonpregnant women between 19 and 38 yr of age and from 115 unselected pregnant women between 17 and 45 yr of age (35 in the first trimester, 22 in the second trimester, 38 in the third trimester, and 20 within 2 d of delivery). Samples of umbilical cord blood and amniotic fluid were taken from women in the second and third trimesters and at delivery. The Se content was measured by atomic absorption spectrometry (AAS), plasma MDA concentration by thiobarbituric acid reaction, and Se-dependent GSH-Px spectrometrically. Blood and plasma Se contents of nonpregnant women were below those considered adequate, indicating low selenium intake. In comparison to nonpregnant women, pregnant women had significantly decreased whole-blood and plasma Se levels in the second and third trimesters and at delivery. The significant drop of whole-blood SeGSH-Px activity was observed in the first trimester of pregnancy and its lower activity was maintained until delivery. A significant drop in plasma SeGSH-Px activity occurred in the second trimester and attained the minimal level at delivery. The Se level and SeGSH-Px activity in maternal and umbilical cord blood were at similar levels. Amniotic-fluid SeGSH-Px activity was nondetectable or exceptionally low and its Se content remained unchanged during pregnancy. Plasma levels of MDA were significantly decreased in the second and third trimesters and at delivery. The fetal blood plasma at birth had a lower MDA level compared to the levels of MDA of their mothers at delivery. A low, but significant inverse correlation existed between blood SeGSH-Px activity and plasma MDA content and between plasma Se and plasma MDA contents during pregnancy. A significant decrease of Se and SeGSH-Px activities (antioxidant enzyme) in both blood and plasma suggests a possible drop in total antioxidant status during pregnancy. Elevated MDA plasma levels might be the result of increased lipid peroxidation in placental tissue during pregnancy.     

Self-monitoring of blood glucose in diabetic pregnancy.

Admission to hospital is usually recommended to achieve the best possible diabetic control during pregnancy. We have used blood glucose monitoring at home to find out if patients can achieve equally good control outside hospital. Twenty-five consecutive diabetic patients were studied, of whom 20 had taken insulin before pregnancy. Six of their 14 previous pregnancies had ended in perinatal death. The 25 women performed 4247 blood glucose measurements during their pregnancies. Overall the mean blood glucose concentration was 7.1 mmol/l (128 mg/100 ml); before meals the mean was 6.5 mmol/l (117 mg/100 ml). Mean concentrations were lower in the third trimester, but at no stage was control in hospital significantly better than at home. The mean hospital stay before delivery was 22 days, and all patients had live babies. Monitoring blood glucose concentrations at home produces greater understanding and motivation among patients, improves control early in pregnancy, and shortens time spent in hospital.     

Glycosylated haemoglobin concentrations in mothers of large babies.

Mothers who have big babies may have had abnormal glucose tolerance during pregnancy. Glycosylated haemoglobin (HbA1) concentrations were measured on the first or second day after delivery in 50 women who had had babies weighing over the 95th centile for gestational age and in 50 women who had had normal-sized babies (controls). Nine of the mothers of big babies but only one of the controls had an HbA1 concentration above the normal range. All the women had normal glucose tolerance and HbA1 concentrations six weeks after delivery. Measuring HbA1 concentration in the first two days after delivery in mothers of large babies may identify gestational diabetics.     

The apparent effect of iron supplementation on serum selenium levels in teenage pregnancy

Numerous studies have suggested a significant role of selenium in the prevention of gynecological carcinoma. These were epidemiological and prospective in humans and therapeutic in laboratory animals. However, no studies have been reported regarding the normal serum selenium levels during pregnancy. The maternal total blood volume increases 30-50% during the second and third trimesters, resulting in lower measured serum levels for those metabolites, which are not increased significantly during pregnancy. A longitudinal study of the serum selenium levels in teenage pregnancy during the last two trimesters and 3 mo postpartum showed progressive elevation from 49 +/- 7 microg/dL after the 32nd week of pregnancy to 114 +/- 7 microg/dL at term, which was statistically significant (p < or = 0.001). Prenatal supplementation with 18 mg of iron per day prevented this elevation. The results of this study suggest that serum selenium levels in women normally double during pregnancy and this doubling is prevented by the minimal daily supplementation of 18 mg of iron, which may be due to increased absorption of selenium into the erythrocytes and incorporation into the glutathione peroxidase enzyme.     

Susceptibility to Pregnancy Disease in Ewes and its Relation to Gestastional Diabetes

The ability of 8 pregnant ewes to maintain glucose homeostasis following an intravenous glucose load (glucose tolerance test) and during starvation in late pregnancy was studied. Following an intravenous load 2 out of 7 ewes tested showed an impaired insulin secretion during the first 10–15 min. An increase in plasma insulin concentration was found 50–60 min after the injection. The results of the effect of a starvation on a number of blood constituents are demonstrated. Two of the twin–pregnant ewes developed symptoms of pregnancy disease following starvation, these were the same ewes that showed an impaired insulin secretion after the glucose load. However, no difference was demonstrated in the clinical chemical parameters whether the experimental ewes developed pregnancy disease or not.     

Development and characterization of a novel rat model of type 2 diabetes mellitus: the UC Davis type 2 diabetes mellitus UCD-T2DM rat

The prevalence of type 2 diabetes (T2DM) is increasing, creating a need for T2DM animal models for the study of disease pathogenesis, prevention, and treatment. The purpose of this project was to develop a rat model of T2DM that more closely models the pathophysiology of T2DM in humans. The model was created by crossing obese Sprague-Dawley rats with insulin resistance resulting from polygenic adult-onset obesity with Zucker diabetic fatty-lean rats that have a defect in pancreatic beta-cell function but normal leptin signaling. We have characterized the model with respect to diabetes incidence; age of onset; longitudinal measurements of glucose, insulin, and lipids; and glucose tolerance. Longitudinal fasting glucose and insulin data demonstrated progressive hyperglycemia (with fasting and fed glucose concentrations >250 and >450 mg/dl, respectively) after onset along with hyperinsulinemia resulting from insulin resistance at onset followed by a progressive decline in circulating insulin concentrations, indicative of beta-cell decompensation. The incidence of diabetes in male and female rats was 92 and 43%, respectively, with an average age of onset of 6 mo in males and 9.5 mo in females. Results from intravenous glucose tolerance tests, pancreas immunohistochemistry, and islet insulin content further support a role for beta-cell dysfunction in the pathophysiology of T2DM in this model. Diabetic animals also exhibit glycosuria, polyuria, and hyperphagia. Thus diabetes in the UC Davis-T2DM rat is more similar to clinical T2DM in humans than in other existing rat models and provides a useful model for future studies of the pathophysiology, treatment, and prevention of T2DM.     

Intergenerational effects of birth weight on glucose tolerance and reproductive performance

Women who were themselves small-for-gestational age (SGA) are at a greater risk of adulthood diseases such as non-insulin-dependent diabetes mellitus (NIDDM), and twice at risk of having an SGA baby themselves. The aim of this study was to examine the intergenerational pig. Low (L) and normal (N) birth weight female piglets were followed throughout their first pregnancy (generation 1 (G1)). After they had given birth, the growth and development of the lightest (l) and heaviest (n) female piglet from each litter were monitored until approximately 5 months of age (generation 2 (G2)). A glucose tolerance test (GTT) was conducted on G1 pig at 6 months of age and again during late pregnancy; a GTT was also conducted on G2 pigs at 4 months of age. G1 L offspring exhibited impaired glucose metabolism in later life compared to their G1 N sibling but in the next generation a similar scenario was only observed between l and n offspring born to G1 L mothers. Despite G1 L mothers showing greater glucose intolerance in late pregnancy and a decreased litter size, average piglet birth weight was reduced and there was also a large variation in litter weight; this suggests that they were, to some extent, prioritising their nutrient intake towards themselves rather than promoting their reproductive performance. There were numerous relationships between body shape at birth and glucose curve characteristics in later life, which can, to some extent, be used to predict neonatal outcome. In conclusion, intergenerational effects are partly seen in the pig. It is likely that some of the intergenerational influences may be masked due to the pig being a litter-bearing species.     

Factors predicting the course of diabetes mellitus in hyperthyroid patients

The relationship between changes in glucose tolerance with treatment of hyperthyroidism and various factors that might be relevant to carbohydrate metabolism were investigated in 64 hyperthyroid patients with abnormal glucose tolerance, including 35 cases with fasting plasma glucose (FPG) levels of 140 mg/dl or more. All patients had diffuse toxic goiter. After correction of the hyperthyroidism, glucose intolerance improved in almost all cases, even in cases with fasting hyperglycemia, but diabetes mellitus in patients with FPG above 140 mg/dl and/or delta IRI/delta PG X 30' during a 50-g oral glucose tolerance test below 0.10, persisted. Patients who showed diabetic glucose tolerance even after remission from thyroid dysfunction had significantly lower delta IRI/delta PG X 30' values and a higher incidence of family histories of diabetes mellitus than those not showing diabetic glucose tolerance. There were no significant differences in serum T3 and T4 levels between these two groups of patients. The findings suggest that predisposition to diabetes may be an important factor in persistent glucose intolerance in the hyperthyroidism of Graves' disease. The FPG and delta IRI/delta PG X 30' values may be useful in predicting which patients with hyperthyroidism will have permanent diabetes.     

Effect of short-term clofibrate on glucose metabolism and insulin secretion in patients with mild maturity-onset diabetes mellitus

The effect of 1 week clofibrate administration on glucose and insulin responses to oral glucose and to intravenous tolbutamide was evaluated in 21 patients with mild maturity-onset diabetes (fasting plasma glucose 108-152 mg/100 ml). After treatment, oral glucose tolerance and hypoglycaemic effect of tolbutamide were significantly improved; plasma insulin response was reduced after glucose and unmodified after tolbutamide; fasting plasma glucose was also significantly reduced. These findings did not correlate with the observed fall in serum lipids. Short-term clofibrate improves glucose metabolism in mild diabetes irrespective of its effects on lipid metabolism. It is suggested that the drug's action may be mediated by reduced insulin resistance.