Antioxidant status and lipid peroxidation in type II diabetes mellitus with and without complications

1. This study was conducted on 467 cases of non-insulin-dependent diabetes mellitus and 180 healthy controls. Lipid peroxidation products in plasma and erythrocytes were assayed as thiobarbituric acid reactive substances, along with the erythrocyte antioxidant enzymes, namely superoxide dismutase, catalase and glutathione peroxidase. In addition, scavenger vitamins A, C and E and reduced glutathione levels in blood were also measured. 2. Lipid peroxidation was significantly raised within the first 2 years of diagnosis, and superoxide dismutase, catalase, reduced glutathione and vitamins C and E were significantly lowered. 3. These changes were correlated with the duration of the disease and were of a higher magnitude with the development of complications. 4. The results suggest that the antioxidant deficiency and excessive peroxide-mediated damage may appear early on in non-insulin-dependent diabetes mellitus, before the development of secondary complications.

Diabetic retinopathy at the time of diagnosis of NIDDM in south Indian subjects

Several studies from the U.K. and the U.S. have shown that retinopathy was present at diagnosis of non-insulin dependent diabetes mellitus (NIDDM) indicating the likelihood of a latent phase of hyperglycaemia for a long period. This study looked for the prevalence of retinopathy at diagnosis of NIDDM in South Indian subjects who have a fairly high prevalence of diabetes and also a high rate of undetected diabetes. One thousand NIDDM subjects with varying duration of diabetes underwent detailed ophthalmoscopic examination for retinopathy. It was noted that the prevalence of retinopathy increased linearly with duration of diabetes. Among the 60 newly diagnosed NIDDM, 4 (6.7%) subjects had background diabetic retinopathy. Using a weighted linear regression analysis with percentage of retinopathy in relation to duration, it was estimated that hyperglycaemia could have been present 4.1 years prior to the diagnosis of NIDDM. Although the prevalence of retinopathy at diagnosis in South Indian NIDDM was lower than the other reported values, in view of the high prevalence of diabetes in Indians, a large number of patients would have the risk of microangiopathy even before diagnosis of diabetes is made.

An association in non-insulin-dependent diabetes mellitus subjects between susceptibility to retinopathy and tumor necrosis factor polymorphism

In IDDM an association between diabetic retinopathy and polymorphic markers of MHC has been described. However, these associations are complicated by a primary association between the MHC and IDDM. Because the pathogenesis of retinopathy is likely to be the same in IDDM and NIDDM, NIDDM subjects with retinopathy would be the ideal population to study for an association with MHC markers. The following South Indian subjects were therefore studied: unselected NIDDM (n = 76), unselected IDDM (n = 99), non-diabetic controls (n = 96), NIDDM subjects with maculopathy (MAC), n = 55, NIDDM subjects with proliferative retinopathy (PR), n = 53, and without retinopathy (LTD), n = 46. DNA was amplified and studied using a microsatellite polymorphism located 3.5 kb upstream of TNF-beta within the MHC class III region on the short arm of chromosome 6. No differences in allelic distribution were observed between the random NIDDM subjects and controls (p = 0.17). Differences in allelic distribution were found between unselected IDDM and controls (P = 0.016) and between the NIDDM subjects with maculopathy and/or proliferative retinopathy and no retinopathy (P = 0.006). This association could be accounted for by those patients with proliferative retinopathy (MAC vs LTD, p = 0.23; MAC vs PR, p = 0.07; and PR vs LTD, p = 0.002).

Familial aggregation of type 2 (non-insulin-dependent) diabetes mellitus in south India; absence of excess maternal transmission

The family histories of 976 South Indian Type 2 diabetic patients were recorded in a questionnaire-based survey to establish whether the excess maternal transmission of Type 2 diabetes reported in low prevalence Europid populations was also evident in this medium prevalence population. In 450 families (46.1%), no parental history of diabetes was reported. In 423 families with one parent diabetic, 222 fathers (52.5%) and 201 (47.5%) mothers were diabetic. In the remaining 103 (10.6%) families, both parents were diabetic. In contrast to previous studies, we found no evidence for substantial maternal excess in the transmission of diabetes (325 diabetic fathers vs 304 mothers; p = 0.4; p = 0.07 when compared using life table methods). The age of diagnosis of diabetes in probands was lower than that of their diabetic parents (p < 0.001): furthermore increasing parental history of diabetes was associated with an earlier diagnosis of diabetes in probands (p < 0.001). These results emphasize the extensive familial aggregation of Type 2 diabetes in this population but fail to replicate the evidence for excess maternal transmission evident in lower prevalence Europid populations, suggesting ethnic differences in the extent of this phenomenon.

Increased non-angiotensin II [125I]CGP 42112 binding in rat carotid artery after balloon injury

In this study, [125I]CGP 42112, a ligand of high affinity and selectivity for the angiotensin II AT2 receptor, was used to detect and quantify a non-angiotensin II binding site in the balloon-injured carotid artery of the rat. The amount of [125I]CGP 42112 binding was significantly enhanced in the adventitia of the injured arteries. Localization of the binding site using emulsion autoradiography and immunocytochemistry suggests that the binding sites may be expressed by macrophages in the inflamed tissue surrounding the injured artery.

Expression of a novel angiotensin II receptor subtype in gerbil brain

Angiotensin II receptors are highly localized in adult gerbil brain. Apparent receptor number is high in subfornical organ, vascular organ of the lamina terminalis, nucleus of the solitary tract, hippocampus, and in the anterior pituitary gland. In the hippocampus, binding is localized to the stratum oriens, radiatum, the lacunar molecular layers of the CA1 subfield, and the molecular layer of the gyrus dentatus, with a medial to lateral and anterior to posterior gradient in receptor expression. Binding is absent from the pyramidal layer of the CA1 subfield and from the granular cell layer of the gyrus dentatus, areas rich in angiotensin IV binding. Characterization in the hippocampus revealed the presence of a high affinity receptor, sensitive to incubation with the guanine nucleotide GTP gamma S, and displaced by angiotensin II = angiotensin III < Sar1-Ile8-angiotensin II, but not by angiotensin IV or other angiotensin fragments, the AT1 receptor antagonist losartan, or the AT2 ligands CGP 42112 or PD 123177. In other brain areas, binding was equally insensitive to displacement by AT1 or AT2 ligands, with the exception of binding in the olfactory bulb, which was totally displaced by CGP 42112 and PD 123177, but not by losartan. In the gerbil, most of the brain and pituitary angiotensin II receptors are different from the AT1, AT2 and AT4 subtypes, and should be considered 'atypical' until further characterization.

Expression of non-angiotensin II -125I-CGP 42112 binding sites on activated microglia after kainic acid induced neurodegeneration

[125I]CGP 42112, first developed to identify angiotensin II receptor subtype 2 (AT2), was recently shown to bind to a novel non-angiotensin binding site in injured rat brain tissue. We addressed the question whether non-angiotensin [125I]CGP 42112 binding appears after kainic acid induced hippocampal neurodegeneration, a process of neuronal cell death at a distance from the toxin injection site. After intraventricular kainic acid injection, we found non-angiotensin [125I]CGP 42112 binding in the hippocampal areas CA3 (4 and 14 days after injection), CA1 and CA4 and the subiculum (14 days after injection). In addition, 14 days after kainic acid injection, [125I]CGP 42112 binding was found in 50% of the animals, in the thalamus, amygdala and piriform cortex, areas receiving projections from the hippocampus and suffering kainic acid induced delayed neurodegeneration. The loss of neurons in these regions was accompanied by an accumulation of activated microglia as demonstrated by immunostaining with the specific antibodies OX-42 and ED1. The time course and regional pattern of OX-42/ED1 positive immunostaining was identical with the appearance and distribution of the non-angiotensin [125I]CGP 42112 binding site. The non-angiotensin [125I]CGP 42112 binding was not detected in brain regions unaffected by kainic acid injection. Our findings indicate the expression of a novel [125I]CGP 42112 binding site on activated microglia. This site appears at a distance from the lesion and may be of importance in the process of neuronal death and brain tissue repair.

Structural predictions of the binding site architecture for monoclonal antibody NC6.8 using computer-aided molecular modeling, ligand binding, and spectroscopy

Monoclonal antibody NC6.8 binds the superpotent sweetener ligand N-(p-cyanophenyl)-N'-(diphenylmethyl) guanidineacetic acid with high affinity (Kd = 53 nM). Using computer-aided molecular modeling and several experimental techniques, such as competitive ligand binding, absorbance spectroscopy, and fluorescence spectroscopy, we have predicted the structure of the variable domain fragment (Fv) and identified the key residues in the combining site of the antibody. We have identified nine specific amino acids as being involved in ligand recognition and complexation. Most notable are H:33W, which is responsible for ligand-induced tryptophan fluorescence quenching, H:56R, which forms a salt bridge with the carboxylate moiety of the ligand, and L:34H, which, deep in the binding site, interacts with the cyanophenyl portion of the ligand. Two residues located deep in the putative binding pocket, H:35E and H:50E, provide the negatively charged potential for interaction with the protonated aryl nitrogen and the positive guanidinium group. These modeling predictions were made before the solution of high-resolution structures of the native Fab (2.6 A) and the Fab-ligand complex (2.2 A). Comparisons between the theoretical model and experimental native and liganded Fab structures are made.

Noradrenaline-induced hypothermia is suppressed in the vagotomized cold-exposed pigeon

Vagotomized (VX) pigeons studied 2 days after surgery exhibited a significant decrease in cloacal temperature (Tb) and respiratory rate (Rf), and an increase in heart rate (Hf) and metabolic rate (M) at the thermoneutral zone, when compared with sham-operated (SVX) pigeons. The effect of intravenous noradrenaline (NA) on Tb, Rf, Hf and M was examined in SVX and VX-pigeons at 15 degrees C. Following NA administration, the Tb and Rf in the SVX-birds dropped from the preinjection level, but in VX-pigeons, they were not significantly altered. In SVX-pigeons, a total suppression of shivering was apparent following NA-injection, while in the majority of VX-pigeons, shivering was only slightly affected or even increased. The Hf in both SVX- and VX-birds increased following NA-injection. The responses to reserpine were qualitatively similar to NA, although much slower. There were no differences between SVX- and VX-birds with regard to Tb, M and Rf following acetylcholine (ACh) and eserine (Ese) injection. Hf increased after ACh+Ese administration in SVX-pigeons, but in VX-birds, it decreased after an initial surge. Shivering was suppressed for 18-20 min in SVX-birds and 30-50 min in VX-birds. It is suggested that the lack of the hypothermic effect of NA in VX-birds is due to the maintenance of oxygen uptake with unimpaired capacity for shivering.

Insulin receptor substrate-1 gene mutations in NIDDM; implications for the study of polygenic disease

Variations in the coding regions of the insulin receptor substrate-1 (IRS-1) gene have recently been suggested to contribute to the susceptibility of non-insulin-dependent diabetes mellitus (NIDDM). The purpose of this study was to examine the role of the IRS-1 missense mutations at codons 972 (glycine to arginine) and 513 (alanine to proline) in two diverse populations from South India and Finland at high risk for NIDDM. DNA was amplified and digested with restriction enzymes BstN1 to detect the codon 972 mutation and Dra III to detect the codon 513 mutation. The codon 513 mutation was not found in the study subjects. The codon 972 mutation was present in 10.3% of 126 middle-aged NIDDM subjects and 5.3% of 95 matched control subjects in the South Indians (p = 0.17). In elderly Finnish subjects the frequency of the mutation was 7.5% in 40 NIDDM subjects and 7% in 42 matched control subjects. The frequency of codon 972 mutation in the South Indian NIDDM subjects was very similar to the two previously published studies in Danish and French subjects although each study individually fails to reach conventional levels of significance. The data from all four ethnic groups were analysed together after ascertaining that significant heterogeneity did not exist between the studies. Overall, the frequency of the codon 972 mutation is found in 10.7% NIDDM subjects and 5.8% control subjects (p = 0.02). These studies suggest that the codon 972 mutation of the IRS-1 gene might act as a susceptibility gene predisposing to NIDDM in certain ethnic groups.

Proteinuria in NIDDM in south India: analysis of predictive factors

There are few data on the risk factors for diabetic nephropathy in the Asian Indian population, although several studies have shown a high prevalence of the disease in this ethnic group. This study also aimed to assess the role of hyperglycaemia and hypertension in the causation and course of nephropathy in this population, which has low rates of obesity. Retrospective analysis of two groups of non-insulin dependent diabetic (NIDDM) patients, one without proteinuria (< 100 mg/day, n = 25) and the other with proteinuria (> or = 500 mg/day, n = 25), matched for age, sex, duration of diabetes and body mass index (BMI) was done to study the factors predisposing to proteinuria and also its progression during a 2 year follow-up. Logistic regression analysis showed that the factors contributory to proteinuria were initial HbA1 and initial systolic blood pressure. The average proteinuria during the follow-up was dependent on the initial and average systolic and diastolic blood pressure values. No correlation was seen between cholesterol or triglyceride values and the change in proteinuria. Creatinine clearance deteriorated in the proteinuric group and this was related to the presence of proteinuria and initial diastolic blood pressure. This study emphasizes the importance of blood pressure in the progression of diabetic nephropathy, even in people who have low BMI. Therefore, good control of blood pressure has an important role to play in the management of this condition.

Characterization of endothelinA receptors in cerebral and peripheral arteries of the rat

We have characterized and quantified endothelin receptors in rat brain (anterior cerebral) and peripheral (aorta, carotid, and caudal) arteries, with the use of [125I]endothelin and quantitative autoradiography. Endothelin binding was saturable, of high affinity, and totally displaced by the selective endothelin ETA antagonist BQ 123. A single class of ETA receptors is located in the medial layer of peripheral and cerebral arteries, and its quantification by autoradiography allows study of their regulation and function.

Kidney angiotensin II receptors and converting enzyme in neonatal and adult Wistar-Kyoto and spontaneously hypertensive rats

The aim of the present study was to correlate the development of the renin angiotensin system (RAS) in the kidney of the rat with the development of genetic hypertension. Immature (1-week-old) and adult (12-week-old) normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive kidney rats (SHR) were used for quantification of angiotensin II (ANG II) receptors and angiotensin converting enzyme (ACE) binding sites using quantitative autoradiography. In both neonatal and adult animals of either strain, ANG II receptors were of AT1 subtype. In all kidney areas of 1-week-old rats. ANG II receptor density was higher in SHR than WKY. Binding density increased with age in WKY rats; thus, in the glomeruli and the outer stripe of the outer medulla of 12-week-old WKY, binding was significantly higher than that present in age-matched SHR. [125I]351A binding to ACE was highest in the outer medulla and not detectable in glomeruli. In 1-week-old rats, binding to ACE was higher in WKY than in SHR strain. No differences in ACE binding were found between adult SHR and WKY rats, with the exception of the inner stripe of the outer medulla, where no binding was detected in SHR. Our results support the hypothesis that the RAS in kidney is developmentally regulated and is involved in the development and maintenance of genetic hypertension in SHR.

Family studies of non-insulin-dependent diabetes mellitus in South Indians

Though a genetic basis for non-insulin-dependent diabetes mellitus (NIDDM) is clear, the likely mode of inheritance is not known. The segregation of NIDDM was studied in 64 nuclear South Indian pedigrees (449 individuals) ascertained through an affected proband having both parents and more than 1 sibling alive and available for oral glucose tolerance testing. A high proportion of parents were found to be of abnormal glucose tolerance [89 of 128 (70%) diabetic and 11 of 128 (9%) impaired]. Complex segregation analysis was performed using (1) POINTER which implements the mixed model and distinguishes major gene, multifactorial and non-transmitted environmental contributions to affection and (2) COMDS which implements an oligogenic model with major gene, modifier gene and environmental contributions to a) affection and b) diathesis (an ordered polychotomy amongst non-affected family members, based on 2-h plasma glucose level). Using POINTER, there was no formal support for a major gene and the most parsimonious solutions were achieved with multifactorial models. Using COMDS, we found i) significant improvements in models when information on glucose levels in nondiabetic family members (diathesis) was included, ii) support for segregation of a diallelic gene as well as background familial resemblance, and iii) under the best-supported model, this diallelic locus featured incomplete dominance (d = 0.8) and a disease-predisposing allele frequency of 14%. In South Indians, segregation of NIDDM is inadequately described by simple major gene models: more complex models provide more satisfactory descriptions. This finding, if applicable in other populations, has important implications for the search for diabetes-susceptibility genes.

Apolipoprotein D gene polymorphism: a new genetic marker for type 2 diabetic subjects in Nauru and south India

Type 2 diabetes is characterized by abnormalities in both glucose and lipoprotein metabolism and genes involved in lipid metabolism are legitimate candidates for involvement in Type 2 diabetes. We have previously reported an association in Nauruans between a Taq 1 polymorphism of the apolipoprotein D gene (apo D) and Type 2 diabetes. In this study these findings were investigated further in the Nauruan population as well as two other ethnic groups. In South Indian subjects, there was a significant difference in genotype distribution of apo D genotypes between diabetic subjects (n = 110) and controls (n = 88; p = 0.004) which was similar to that previously found in the Nauruan subjects. No such association was seen in elderly Finnish subjects (diabetic n = 69; impaired glucose tolerance n = 26 and normal glucose tolerance n = 31). Linkage between the apo D polymorphism and diabetes in 12 Nauruan families was only excluded under a highly penetrant dominant model and was unlikely under other single gene models. Since the beta cell glucose transporter gene (Glut 2) is found in a similar chromosomal location to apo D, South Indian subjects (diabetic n = 95 and controls n = 56) were typed at this locus. No association between diabetes and the Glut 2 Taq I polymorphism was found in the South Indian subjects. Furthermore, there was no evidence of linkage disequilibrium between the apo D and Glut 2 genes. In conclusion, apo D might act as a modifying gene for Type 2 diabetes in some ethnic groups.

Seripauperins of Saccharomyces cerevisiae: a new multigene family encoding serine-poor relatives of serine-rich proteins

A gene, PAU1, has been cloned from Saccharomyces cerevisiae and sequenced. It is located in a telomeric region, probably on chromosome IV, and contains an open reading frame encoding a protein of 120 amino acids (aa) (approx. 13 kDa). The deduced sequence is nearly identical to two other genes found in GenBank (named PAU2 and PAU3 by us), which are located close to the ends of chromosomes V and III, respectively. Blotting of separated chromosomes with a PAU1 probe at high stringency revealed that at least six chromosomes in addition to III, IV and V possessed related sequences, suggesting a large gene family. Probing of an ordered array of phage lambda clones containing yeast genomic DNA inserts ('Olson filters') revealed ten additional hybridizing sequences, located close to the ends of the left and/or right arms of chromosomes I, II, VII, VIII, X, XII, XIV and XV. Transcription of these sequences could not be demonstrated, however, under a wide variety of growth and culture conditions. The deduced PAU1, PAU2 and PAU3 aa sequences are all highly homologous with the SRP1 aa sequences, which contains eight serine-rich tandem repeats of 12 aa each, at its C terminus. This homology is limited, however, to the N-terminal half of SRP1, and does not include the repeats. In fact, PAU1 is quite serine-poor (5.8%), leading to the suggested name of seripauperins for this family of genes.

High prevalence of NIDDM and IGT in an elderly south Indian population with low rates of obesity

OBJECTIVE--To assess the prevalence of diabetes and impaired glucose tolerance (IGT) in the urban and rural elderly population in south India. RESEARCH DESIGN AND METHODS--Urban and rural populations > or = 60 years of age and representative of the areas (873 urban and 588 rural subjects) were screened for diabetes and IGT using fasting and 2-h postglucose capillary blood glucose measurements. RESULTS--In the urban area, 211 (23.7%) had diabetes, and 101 (12.4%) had IGT. In the rural area, 56 (9.9%) had diabetes, and 82 (14.9%) had IGT. The ratio of newly diagnosed to known diabetes was 1:3 in the urban and 1:1 in the rural areas. Positive family history of diabetes, body mass index (BMI), subscapular-to-triceps ratio, and waist-to-hip ratio were significantly associated with diabetes in the urban population. Only age and BMI showed significant association with diabetes in the elderly rural population. None of the tested parameters, except age in the urban subjects, showed association with IGT. CONCLUSIONS--This study highlights the high prevalence of glucose intolerance in elderly south Indians having low mean BMI (mean +/- SD; urban 21.7 +/- 4.6, rural 17.9 +/- 3.3 kg/m2). Although there was a twofold higher prevalence of diabetes in the urban area, the occurrence of IGT was similar in urban and rural populations.

Prevalence of proteinuria in non-insulin dependent diabetes

Proteinuria was estimated in 600 non-insulin dependent diabetes mellitus (NIDDM) patients in 24 hrs collection of urine. The test was repeated at least twice in a year to confirm the persistence of proteinuria. Mild proteinuria (200-500 mg/d) occurred in 94 (15.7%) and nephropathy (> 500 mg/d) in 112 (18.7%) patients. Nephropathy commonly occurred with long-standing diabetes (> 10 years). Development of proteinuria correlated directly with the duration of diabetes, diastolic and systolic blood pressure, age of the patients, serum creatinine and inversely with creatinine clearance. Retinopathy was seen in 75% of those with nephropathy. It is concluded that proteinuria occurs in one third of NIDDM patients and the risk of nephropathy increases with duration of disease.

Expression of a novel non-angiotensin II [125I]CGP 42112 binding site in healing wounds of the rat brain

We characterized a novel non-angiotensin II binding site that is recognized by the angiotensin II AT2 receptor ligand [125I]CGP 42112, in healing brain wounds of adult rats. The binding, which was highest at 3 days after injury, appears to be localized to activated microglia surrounding the wound. The novel CGP 42112 binding site may have a role in the function of microglia and in mechanisms of tissue repair in the brain.

Prevalence of diabetes in pregnant women--a study from southern India

This study was carried out to assess the prevalence of diabetes in southern Indian women during pregnancy. Nine hundred and fifty women having > or = 24 weeks of gestation, attending two general gynaecology centres for antenatal check-ups were screened. Initially, the screening test with 1-h plasma glucose sampling following 50 g glucose load was done and those with glucose values > or = 140 mg/dl were subjected to a 3-h oral glucose tolerance test (OGTT) with 100 g glucose load. Among the 950 women, 6 were known diabetic subjects. Of the other 944, 89 were positive on screening test and 67 of them reported for OGTT. Four were detected to have gestational diabetes mellitus (GDM) (O'Sullivan and Mahan's criteria). Therefore the prevalences of total diabetes and GDM were 1.19% and 0.56%, respectively.

Characterization of melatonin receptors and signal transduction system in rat arteries forming the circle of Willis

The aims of this study were to characterize the melatonin receptors in rat brain arteries forming the circle of Willis. Saturation studies performed using in vitro autoradiography and [125I]iodomelatonin revealed the presence of two binding sites: one with a Kd of 13 pM, and the second characterized by a Kd of 832 pM. Coincubation with a nonhydrolyzable guanine nucleotide analog [guanosine-5'-O-(3-thiotriphosphate)] inhibited 2-[125I]iodomelatonin binding in a concentration-dependent manner, whereas adenine nucleotide adenosine-5'-O-(3-thiotriphosphate) was ineffective. In saturation studies performed in the presence of guanosine-5'-O-(3-thiotriphosphate), the high affinity site was no longer detectable, and the affinity of the receptor was decreased to the high picomolar range. Melatonin, at nanomolar concentrations, was able to inhibit forskolin-stimulated cAMP production in rat circle of Willis arteries. Preincubation with pertussis toxin counteracted the effect of melatonin. Our results demonstrate that melatonin receptors in rat cerebral arteries are linked to their second messenger through a pertussis toxin-sensitive G-protein, similar to what has been described for melatonin receptors in different areas of vertebrate brain.

Pancreatic beta cell function in normoglycaemic offspring of diabetic parents

The aim of the study was to look for any time-realted fluctuation in the pancreatic beta cell function in normal offspring of diabetic parents, over a period of three years. Serum insulin (IRI) and C-peptide (CP) responses to oral glucose were reevaluated three years after the initial study in 25 normoglycaemic offspring of conjugal Type 2 diabetic parents. The mean area under the curve of IRI (AUC IRI) response was higher than normal control value in the offspring at both time points (P < 0.01) and the two values did not differ much. The 2 hr IRI was also significantly higher (P < 0.05) than the control value. CP responses at both time points in the offspring did not differ from the mean control value. Wide fluctuations in the individual IRI were noted on follow-up despite similar plasma glucose response. Follow-up IRI was higher in 6, lower in 5 (+/- 25% of the initial) and remained unaltered in the other 4 offspring. The corresponding CP showed increased values in 3, decreased values in 5 and no change in 7 offspring. The fluctuations were nonuniform in nature among the individuals studied. Disparity between the IRI and CP responses were present in 5 offspring during the follow-up. This study thus shows that wide fluctuations in insulin responses occur even in the normoglycaemic offspring of diabetic parents.

Differences in plasma insulin responses in urban and rural Indians: a study in southern-Indians

Fasting and 2 h post glucose plasma immunoreactive insulin (fasting IRI and 2 h IRI) responses were measured in urban (n = 149) and rural (n = 40) individuals with normal glucose tolerance during an epidemiological survey. In this survey, 900 urban and 1038 rural subjects were screened for glucose intolerance by capillary blood sampling. The respective response rates were 91% and 88%. We had planned to collect venous blood for IRI estimation, i.e. from 180 urban and 200 rural subjects. The compliance for the same was poor from the rural subjects and therefore the number available for IRI estimation was small. The mean +/- SD ages of the urban and rural groups were similar (35.3 +/- 9.9 and 38.6 +/- 13.1 years, respectively). The rural population had lower body mass index (BMI) and subscapular:triceps ratio compared to the urban group (p < 0.001). The total calorie consumption was lower and physical activity was higher in rural population. Fasting and 2 h insulin values in urban population were 16.6 +/- 9.4 mU l-1 and 60.6 +/- 42.5 mU l-1 and in rural 6.7 +/- 5.1 mU l-1 and 32.4 +/- 27.8 mU l-1, respectively; the values being significantly lower in the rural population (p < 0.001). Multiple regression analysis showed that in urban population the fasting insulin was correlated to the BMI and the 2h IRI to 2 h glucose, BMI and the subscapular:triceps ratio. In the rural population, similar results were obtained, except in that the 2 h IRI was influenced by the gender also.(ABSTRACT TRUNCATED AT 250 WORDS)