Long-term Changes In Body Weight Research Articles

Synergistic effect of polymorphisms in uncoupling protein 1 and beta3-adrenergic receptor genes on long-term body weight change in Finnish type 2 diabetic and non-diabetic control subjects.

To investigate the independent and combined effects of the Trp64Arg polymorphism of the beta3-adrenergic receptor (beta3AR) gene and the (-3826) A-->G polymorphism of the uncoupling protein 1 (UCP1) gene on body weight change in type 2 diabetic and non-diabetic control subjects during a 10y follow-up study. Controlled 10y follow-up study with baseline, 5 and 10y examinations. 70 newly diagnosed, middle-aged type 2 diabetic patients and 123 non-diabetic control subjects from eastern Finland. Anthropometric measurements, blood pressure, oral glucose tolerance test, plasma insulin, plasma C-peptide and HbA1c. Genotypes by polymerase chain reaction followed by enzymatic digestion. No significant differences were found in the frequencies of the two polymorphisms between diabetic and control subjects. The polymorphisms were not cross-sectionally or longitudinally associated with body weight or BMI in diabetic or control subjects. When the diabetic and control subjects were analysed together, the change in the mean body weight was significantly greater among the subjects with both polymorphisms (n = 11) than among those with no polymorphisms (n = 103; change in weight 6.5 +/- 2.5% vs -0.2 +/- 0.8%, P=0.036, and change in Body Mass Index 8.5 +/- 2.6% vs 2.0 +/- 0.8%, P= 0.060, mean +/- s.e.m.). The simultaneous existence of the two polymorphisms was associated with a tendency to gain weight suggesting a synergistic effect of these polymorphisms on body weight gain.

Excitotoxic lesions of the lateral hypothalamus made by N-methyl-d-aspartate in the rat: behavioural, histological and biochemical analyses

The purpose of this study was to determine whether the excitotoxin N-methyl-d-aspartate (NMDA) could be used to make lesions within the lateral hypothalamus and what effect they had on regulatory behaviour. Larger doses of NMDA were effective in the lateral hypothalamus but tended to spread into adjacent structures; smaller doses made lesions which were contained within the lateral hypothalamus and zona incerta. Lesions which damaged the lateral hypothalamus and surrounding tissue had no effect on the concentration of dopamine (or its metabolites) in the dorsal or ventral striatum. The large lesions, including extrahypothalamic damage, were associated with long-term deficits in lab chow and water intake, but rats with lesions restricted to the lateral hypothalamus made good recoveries, eating and drinking normally from around the tenth day post-operation. Body weight gain was normal in these rats, though there was a long-term loss of body weight compared to controls. Unoperated rats with food intake yoked to lesioned rats showed identical long-term changes in body weight, suggesting that the changes in body weight of lesioned rats may be a reflection of changes in eating and drinking rather than a disruption of a body weight set-point mechanism. Motor deficits were not found; all rats were able to consume without difficulty saccharin solutions. All lateral hypothalamic lesioned rats failed to respond to dehydrating, dipsogenic or glucoprivic challenges. It is concluded that NMDA is an effective toxin in the rat lateral hypothalamus, sparing ascending dopamine fibres, and that the main effect of such lesions is an impairment in responding to physiological challenges.

Performance and extinction of lever press behavior following chronic administration of desipramine to rats.

The effect of repeated administration of desipramine (DMI) on the acquisition, performance, and extinction of a lever press response for food reward was studied. Chronic administration of DMI caused a reduction in pressing under a CRF schedule both in naive and well-trained rats. Responding during extinction sessions did not differ between saline-treated rats and rats given DMI chronically. In addition, chronic administration of DMI reduced the body weight and food intake of rats on either a free-feeding or a restricted-feeding schedule. Consequently, lever pressing was also studied in a group of rats whose body weight was regulated to match the body weight of rats were administered DMI chronically. In comparison to this control group, rats administered DMI chronically responded significantly less during both reinforcement and extinction sessions. These results fail to replicate earlier reports that chronic DMI administration produces increased resistance to extinction. The results also show that assessment of food-motivated performance in rats treated chronically with DMI is difficult because of long-term changes in body weight and food intake.

A model for the prediction of energy balance and body weight.

A model for changes in energy balance and body weight is described which can be written as an iterative computer program. Medium and long-term changes in body weight resulting from random daily fluctuations in energy balance are quantitatively predicted. Body weight varies periodically about a mean value to to the extent of +/- 1 kg over a span of a few weeks. Long-term weight stabilization is the result of a dynamic equilibrium between energy intake and output which depends on activity and tissue metabolism. A lean : fat tissue deposition ratio defines the metabolic type of individual. This ration, which is constant for each individual, governs the proportions in which these tissues are both deposited and mobilized. In the model, the ratio has an important effect on the magnitude and composition of the weight gains resulting from over-eating. It is suggested that the differences in response which have been observed in over-eating experiments result from inter-individual differences in this ratio.

Effects of estradiol implants on body weight regulation in castrated and intact female rats.

The long-term effects of subcutaneous 17β-estradiol benzoate (EB) capsules on body weight regulation were examined in intact and castrated female rats. EB treatment of intact female rats and EB treatment begun simultaneously with ovariectomy resulted in long-term body weight changes similar to those of untreated control animals. However, when a delay was introduced between ovariectomy and EB treatment, and “obesity” was allowed to develop, EB treatment reduced the rate of body weight gain in proportion to the level of “obesity.” These data show that the subcutaneous implantation of Silastic capsules is an effective technique for providing long-term hormone replacement therapy in rats. In addition, consistent with a “set-point” formulation of body weight regulation, the present work indicates that endogenous estradiol levels serve as an important contribution to the maintenance of long-term energy balance in female rats. (Endocrinology 95: 1733, 1974)