Effects of cycles of food restriction followed by ad libitum refeeding on body composition and energy expenditure in obese rats.

Male Wistar rats rendered obese by a cafeteria diet were subjected to three successive cycles alternating food restriction with ad libitum cafeteria-diet feeding (WC rats). Body composition, energy intake, energy required for maintenance, and oxygen consumption were studied. Results were compared with those for rats fed a standard stock diet (CON rats) or a cafeteria diet (CAF rats).

Tritium dilution space measurement is not modified by a doubling in fluid intake.

The purpose of this study was to examine the effects of a doubling in water intake on the total body water measured by the tritium dilution technique. Overdrinking was obtained by presenting tap water and sweet water to the rats. Total body water was measured twice, tritium dilution vs.

Massive overfeeding and energy balance in men: the Guru Walla model.

To determine the magnitude of the thermogenic response to a massive long-term overfeeding, an energy-balance study was carried out in nine lean, young Cameroonian men participating in a traditional fattening session: the Guru Walla. Food intake, body weight, body composition, activity, and metabolic rates were recorded during a 10-d baseline period and over the 61-65 d of fattening. Total energy expenditure (TEE) was measured by using doubly labeled water during the baseline period and the final 10 d of Guru Walla.

n-3 polyunsaturated fatty acids raise low-density lipoproteins, high-density lipoprotein 2, and plasminogen-activator inhibitor in healthy young men.

The effects of a moderate supplementation in n-3 polyunsaturated fatty acids (PUFAs) were investigated in 36 young healthy adult males. Factors investigated were lipoprotein (including HDL subfractions and apolipoproteins) and hemostasis indexes, assessed by platelet aggregation and plasminogen-activator-inhibitor (PAI) activity. Fat-controlled diets were prescribed, one with and one without a fish-oil supplement (control diet), successively during 3 wk in random order.

Effects of ovarian steroids on energy balance in rats fed a highly palatable diet.

The effects of progesterone and estradiol on body weight, energy intake, energy expenditure, body composition, and brown adipose tissue activity were investigated in female rats fed a highly palatable diet (association of chow and full milk with sugar), which, by itself, induced an increase in food intake and energy expenditure. Progesterone and estradiol were administered in the form of implants. Ovariectomized animals were used in the estradiol studies.

A kappa opiate agonist, U50,488H, enhances energy expenditure in rats.

The effect of U50,488H (a selective kappa opiate agonist) on oxygen consumption was measured in either resting and free-moving rats. In both states, U50,488H provokes an increase in oxygen consumption. In resting rats, the increase occurs at lower doses than in free-moving rats.

Lowering of HDL2-cholesterol and lipoprotein A-I particle levels by increasing the ratio of polyunsaturated to saturated fatty acids.

The protective role of high-density lipoproteins (HDLs) has been attributed to the subfractions HDL2 (according to the density) and lipoprotein A-I (LpA-I) (according to the composition in apolipoproteins). We investigated the effect of a high ratio of polyunsaturated to saturated fatty acids (P:S) on these subfractions in a homogeneous group of young adult males. Two prescribed diets were consumed successively at the subjects' homes for 3 wk each in a random order; one diet contained 70 g butter (P:S 0.

Evidence of enhanced storage capacity in adipose tissue of genetically fat chickens.

The storage capacity for plasma triglyceride in abdominal adipose tissue has been investigated in two lines of chickens selected for either high or low adiposity (fat line and lean line, respectively). Adipose tissue cellularity and lipoprotein lipase (LPL) activity were estimated in 2- and 5-wk-old birds. In 2-wk-old birds, cellularity and LPL and glycerophosphate dehydrogenase (GPDH) activity were evaluated in the stromavascular fraction.

Abnormal fatty acid utilization by cultured cardiac cells from 7-day-old obese Zucker rats.

Fatty acid utilization by muscle and nonmuscle heart cells in culture has been investigated in the 7-day-old Zucker rat to determine if this tissue could contribute to the lower energy expenditure reported in obese rats at the onset of obesity. The partitioning of oleate to oxidation and esterification products and the effect of genotype on this partitioning according to cell types were studied. Results showed that the fatty acid beta-oxidation and its esterification in neutral lipid was decreased by 30% in beating muscle cells from obese animals when compared with those from lean animals.

Increased lipoprotein lipase content in the adipose tissue of suckling and weaning obese Zucker rats.

The aim of this study was to determine whether the increase in lipoprotein lipase activity displayed by the adipose tissue of obese (fa/fa) rats as compared with that of lean (Fa/fa) rats could be ascribed to a change in the content or in the catalytic properties of the enzyme. The question was addressed in rats of two ages: in 7-day-old suckling and in 30-day-old post-weaning pups. Inguinal fat-pads were removed surgically (7 days of age) or after killing (30 days of age), and acetone-extract powders were prepared.

A method for separating cultured preadipocytes according to their density: application to stromal cells from overfed suckling rats.

The stroma vascular fraction of adipose tissue consists of a heterogeneous cell population; not all the cells in this compartment undergo adipose conversion in primary culture. A density gradient centrifugation procedure was used to separate cultured cells on the basis of their triglyceride content. This method was applied to both stroma vascular cells from rat adipose tissue and to a 3T3 F442A preadipose cell line as a reference.

[Characterization and differentiation of rat preadipocytes in primary culture].

Using a density gradient medium, we isolated homogeneous cell populations from the inguinal tissue of 3-day old rats. In primary culture we obtained, for the first time, the differentiation of 99% of the cells in the presence of a physiological concentration of insulin (10(-9) M). This model closely mimicked the events occurring during normal mammalian adipose development, i.

Development under the control of insulin of lipogenic enzymes, lipoprotein lipase, isoproterenol and glucagon sensitivity in differentiating rat preadipocytes in primary culture.

In preadipose cellular fractions (I, II and III) isolated by density gradient centrifugation from the inguinal tissue of young rats, we followed the activity of fatty acid synthetase, ATP citrate lyase and lipoprotein lipase during differentiation in culture. 1.5 nM insulin when added at confluence markedly induced the activity of ATP citrate lyase and fatty acid synthetase in the cells derived from the lighter fractions (I and II).

Effects of slimming and composition of diets on VO2 and thyroid hormones in healthy subjects.

Oxygen consumption and plasma thyroid hormone concentrations are modified by both low- and high-calorie diets. It has been suggested that the trigger may be changes in weight ("adipostatic" hypothesis involving the difference between the actual weight and the "set point") or changes in amount of carbohydrate in the diet ("carbohydrate" hypothesis). Two experiments were performed in order to test both hypotheses.

Genetic approach of family obesity: study of HLA antigens in 10 families and 86 unrelated obese subjects.

HLA A and B typing was performed in 86 unrelated obese subjects and in 10 families including at least one parent and one obese sibling. The results in the series of unrelated subjects show no significant difference in antigen frequencies as compared to the control series. However in the 10 families studied, a group of 5 families is characterized by a high penetrance of obesity.

Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3--4 days.

Seven healthy adult men, five shift-workers and two non-shift-workers (from 21 to 36 years; mean = 26.4) volunteered to record what and when they ate, both at work and at home, every day, during eight consecutive weeks (Oct. - Dec.

Measure of total body water, using infrared spectrometry of heavy water.

The total body water can be assayed by the measurement of the diffusion space of heavy water. A well reproducible and inexpensive method is the infrared spectrometry, using two differential comparisons.

Effects of severe diet restriction on the oxygen consumption of obese women during exercise.

Eleven moderately obese, but otherwise healthy, young women were studied for three days while being fed their normal, unrestricted diet and then again for a two week period while being fed an energy-restricted, high-protein diet--220 kcal (0.92 MJ)/day as casein. Oxygen consumption (VO2) was measured 32 times for each subject, both at rest and during bicycle exercises.

Relationship between plasma insulin, the size and number of adpocytes and habitual calory intake in a group of 186 obese women.

In a group of 186 obese women, no correlation was found between post-glucose load insulinemia, measured at 13:00 hrs, and the degree of overweight, nor between post-glucose insulinemia and mean adipocyte diameter. Significant correlations were found between post-glucose insulinemia and daily caloric intake, and between post-protein insulinemia and mean adipocyte diameter. Post-glucose and post-protein load insulinemia were interrelated.

[Lipid metabolism in rats fed a diet rich in various carbohydrates. I. Results after I.P. injection of lipogenic precursors].

Male rats, Wistar CF strain, weighing 120 g at the beginning of the experiment, were fed during 7 months with one of the following diets, containing 72 p. 100 (w/w) carbohydrate: starch, fructose, glucose and sucrose. These diets were about 18% (w/w) in protein content and were conveniently balanced with respect to vitamins and mineral nutrients.