A B S T R A C T The relationship between the dose of intravenously administered streptozotocin (a N-nitroso derivative of glucosamine) and the diabetogenic response has been explored by use of the following indices of diabetogenic action: serum glucose, urine volume, and glycosuria, ketonuria, serum immunoreactive insulin (IRI), and pancreatic IRI content. Diabetogenic activity could be demonstrated between the doses of 25 and 100 mg/kg, all indices used showing some degree of correlation with the dose administered. Ketonuria was only seen with the largest dose, 100 mg/kg. The most striking and precise correlation was that between the dose and the pancreatic IRI content 24 hr after administration of the drug, and it is suggested that this represents a convenient test system either for both related and unrelated beta cytotoxic compounds or for screening for modifying agents or antidiabetic substances of a novel type. Ability to produce graded depletion of pancreatic IRI storage capacity led to an analysis of the relationship between pancreatic IRI content and deranged carbohydrate metabolism. Abnormal glucose tolerance and insulin response were seen when pancreatic IRI was depleted by about one-third, while fasting hyperglycemia and gross glycosuria occurred when the depletion had reached twothirds and three-quarters, respectively. The mild yet persistent anomaly produced by the lowest effective streptozotocin dose, 25 mg/kg, exhibits characteristics resembling the state of chemical diabetes in humans and might thus warrant further study as a possible model. Finally, the loss of the diabetogenic action of streptozotocin by pretreatment with nicotinamide was confirmed and was shown to be a function of the relative doses of nicotinamide and streptozotocin and of the interval between injections.

BJORNTORP, ANDRE LAMBERT. Physical activity, obesity, and cardiovascular risk factors in children. The Belgian Luxembourg Child Study 11. Obes Res. 1997;s:Physical activity was measured in relation to cardiovascular (CV) risk factors in a randomly selected population of 1028 children from Province de Luxembourg in Belgium, a mainly rural area with a high prevalence of such risk factors among adults and children. Physical activity was estimated as participation in sport activities, a major indicator of leisure-time physical activity in schoolchildren, and physical inactivity was estimated as frequency and duration of television (TV) watching. Boys participated more frequently in sport activities than girls did @=0.001). A majority of the children watched TV daily. After age adjustment, bodyweight (girls, pc0.012; boys, p<0.027) and, in boys, body mass index (BMI) Q~0.039) were related to days per week of TV watching. No significant relationships with other CV risk factors remained after adjustments for BMI. In analyses of independent contributions of age, TV watching, and sports activity on CV risk factors, age showed highly significant relationships. In boys, TV showed relationships with BMI @<0.04) and (borderline) with systolic blood pressure, independent of age and sports activity, whereas the latter was significantly related to subscapular skinfold @<0.04) and (borderline) with triceps GUILLAUME, MICHELE, LEIF LAPIDUS, PER 549-556.Submitted for publication November 2. 1995. skinfold and cholesterol. In girls, no significant independent contributions to risk factor associations were found. The father's education was directly associated with sports activities, whereas the mother being a housewife showed negative relationships to physical activity and positive to TV watching in their children, suggesting socioeconomic influence on the activity patterns of children. Furthermore, registrations suggested less physical activity in the most rural part of the area. It is concluded that children in this mainly rural area watch TV frequently. In boys, physical inactivity, measured both as TV watching and as registrations of sports activities, contributes independently to body fat mass. In girls, no contribution or weaker contributions of physical inactivity were found. This suggests that contributory factors leading to obesity might be different in girls and boys.

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Objective: To analyse the association between nutritional and familial factors and obesity in boys and girls. Design: Randomized, cross-sectional population study. Setting: Province de Luxembourg, Belgium. Subjects: One thousand and twenty-eight boys and girls in age strata 6±8, 8±10 and 10±12 y, comprising 70.3% of primary cohort. Methods: Examinations included anthropometric measurements and questionnaires covering familial, socioeconomic and psychosocial factors. A three day dietary record was obtained in 955 children. This was analysed in relation to the anthropometric data. Results: In comparison with similar studies from other regions and recommended allowances, the intakes of total energy, fat, particularly saturated fat and cholesterol, were high, while consumption of carbohydrate and ®ber was low, as well as the polyunsaturatedasaturated ratio of fat. Total energy intake showed no or weakly signi®cant correlations with anthropometric factors. However, total fat (P 0.045) and saturated fat (P 0.0005) intake showed consistent positive correlations with body mass index (BMI, kgam 2 ) and skinfold thickness, with corresponding negative relationships to carbohydrate intake (P 0.034) in boys. Such relationships were also found when calculated as energy density. These associations were not statistically signi®cant in girls. The high fat, low carbohydrate pattern of the nutritional status seemed to be more pronounced in families where the father had a low level of education (lipids, boys, P 0.0007), and where both parents were obese (saturated fat, boys, P 0.023), suggesting involvement of socioeconomic and familial factors. Conclusion: The lack of correlation between factors indicating obesity and total energy intake suggests that the positive energy balance causing obesity is due mainly to a low energy output. However, since energy intake measurements are imprecise, overeating can not be excluded, particularly since elevated consumption of food with high contents of fat, found in these children seems to be poorly regulated.

The Province of Luxembourg is an area in Belgium with a high prevalence of risk factors for cardiovascular disease and non-insulin-dependent diabetes mellitus among adults. In the present study, children in the age groups 6-8, 8-10, and 10-12 years were selected at random from school classes (n = 1,028), with a participation rate of 70.3%. Anthropometric factors, blood pressure, and fasting blood glucose, plasma cholesterol, triglyceride, and insulin levels were measured in 1992. All anthropometric and metabolic variables increased with age, except for waist: hip circumference ratio in boys and cholesterol in girls. In the oldest group, girls who had passed menarche were taller and heavier and had greater skinfold, body mass index, insulin, and systolic blood pressure values but lower total cholesterol levels and waist: hip ratios than girls who had not passed menarche. Boys had lower skinfolds and higher waist: hip ratios than girls in all age groups, and were significantly shorter and lighter in the oldest age group. There was no difference in body mass index between the two sexes. Girls had higher triglyceride and insulin levels in the 10- to 12-year age group, lower blood glucose values in the 8-10 and 10-12 age groups, and lower diastolic blood pressures in the 8-10 age group. Obesity, blood glucose, triglycerides, insulin, and blood pressure were highly interrelated. Cholesterol, triglycerides, insulin, and blood pressure values were all among the highest of values previously reported in other studies. The deciles of body mass index above 50 appeared to be particularly elevated, suggesting that obesity, when present, was pronounced in this population of children. These findings suggest an accumulation of genetic susceptibility to cardiovascular disease and non-insulin-dependent diabetes mellitus in this stable, ethnically homogeneous, and rather isolated part of continental Europe.