Milk intake of mouse pups was controlled by adjusting litter size at birth to four, nine or 20 pups. Litters of nine were considered as control groups. In adult animals many differences were seen among the three groups which had received the same diet ad libitum after weaning. Differences in body lipids largely accounted for the differences in body weight in both males and females. In parametrial adipose tissue, adipose cells, compared to those of controls, were enlarged and more numerous in mice from small litters, and smaller and less numerous in mice from large litters. After an overnight fast, the insulin response to glucose loading was highest in the obese group of mice, while it was absent in the lean group, suggesting permanent impairment in the secretion of insulin. Liver slices from animals which were bred in small litters incorporated more [U14C]-glucose into triglyceride moieties and cholesterol esters. Some of the metabolic changes in adipose tissue were related to cell size. With increasing litter size, glucose was incorporated into glycogen in muscle to a greater extent. Thus early feeding patterns induced permanent morphological, metabolic and hormonal changes in adults. Animals overfed in early life became obese and underfed animals remained lean when adults.

1. Four groups of rats were fed for 49 d on one of four semi-purified diets, without added cholesterol and containing 230 g/kg of the following isolated proteins: casein, whey, soya-bean or sunflower.2. Whey, soya-bean and sunflower proteins, when compared with casein, decreased the level of serum high-density-lipoprotein (HDL)-cholesterol. These low cholesterol levels were accompanied by an increase in the daily faecal excretion of neutral sterols and bile acids in the case of soya-bean protein, and by a decrease in the liver cholesterol content, when rats were fed on whey protein.3. Considering the amino acid composition of the four purified proteins, we observed that serum total and HDL-cholesterol levels had a significant positive correlation with tyrosine and glutamic acid, and a negative correlation with cystine and alanine.4. The present study showed that the hypocholesterolaemic effect of dietary proteins was not related to their animal or vegetable origin.

Adult genetically obese fafa rats showed a high level of lipogenesis from glucose in liver but not in adipose tissue; pancreatic content and serum levels of insulin were elevated. Glucose uptake anO insulin sensitivity were decreased in muscle, fafa rats and their lean littermates fed a high-fat diet showed increased fat deposits. Serum insulin levels were not significantly affected by diet in either group. The larger the fat cells were, the more actively they utilised glucose; insulin sensitivity was influenced both by diet and cell size. Control rats made obese by a high caloric diet did not show insulin resistance in muscle. --The data indicate that in adult obesity in these rats, even in the presence of marked hyperinsulinism, increased lipogenesis in adipose tissue is not a prerequisite. Rather, fat storage is a consequence of increased uptake of circulating triglycerides. On a diet rich in carbohydrate, adipose tissue fatty acids were mainly of hepatic origin; on a high-fat diet they were of dietary origin.