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Biomedical subjects

M Apfelbaum

Publications and source records attributed to M Apfelbaum.

At least 91 records · Page 5Linked to original sources
PubMed1986

Action of naltrexone on the sexual impairment of obese cafeteria rats.

Two experiments were performed to explore 1) the sexual behavior of male obese cafeteria rats, 2) a possible role of endogenous opiates in the regulation of their sexual behavior. In obese cafeteria rats the proportion of ejaculators and the number of ejaculations per hour were significantly lower compared to controls. Naltrexone provoked an increase in the number of ejaculations/h both in control and cafeteria rats due to an induction of copulatory behavior in sexually inactive rats. Thus nutritional obesity provokes an impairment of sexual behavior and an injection of naltrexone (2.5 mg/Kg IP) lifts this inhibition in a similar way as in inactive, control rats.

Animals↗
PubMed1986

Effects of a 'physiological' dose of triiodothyronine on obese subjects during a protein-sparing diet.

Twenty obese euthyroidian women followed an exclusively proteic diet for 18 days (74 g/day). Half received placebo, and half received 10 micrograms L-triiodothyronine. In the control group, as expected, mean weight loss was 7 percent of initial body weight; serum T3 and TSH decreased; rT3 increased; basal oxygen consumption diminished by 11 percent; nitrogen balance reached equilibrium at day 11. As compared to this group, the T3-treated group lost significantly more weight; serum T3 and TSH increased; rT3 decreased; oxygen consumption remained stable and nitrogen balance did not deteriorate. Thus, the physiological decrease in thyroid hormones provoked by a restricted diet is linked to energy expenditure but not to nitrogen balance equilibrium.

Adult↗
PubMed1985

Increase of uncoupling protein and its mRNA in brown adipose tissue of rats fed on 'cafeteria diet'.

The effect of 'cafeteria diet' on mitochondrial uncoupling protein in brown adipose tissue of rats was examined. 'Cafeteria diet' induced an increase of the 32 kDa uncoupling protein in electrophoresed proteins of brown-fat mitochondria. Use of a cDNA probe corresponding to uncoupling-protein mRNA indicated that this mRNA was increased in rats fed on the 'cafeteria diet'. Nevertheless, this effect was weak compared with that observed in rats adapted to cold.

Adipose Tissue, Brown↗
PubMed1985

[Incidence of lipid changes in rhegmatogenous retinal detachment, retinal vein occlusion and primary chronic glaucoma].

Several studies suggest that vascular factors may play a role in the pathogenesis of rhegmatogenous retinal detachment, retinal vein occlusion and primary chronic glaucoma. We explored the lipoprotein abnormalities in three groups of 45 patients suffering from each of these diseases compared to three control groups. We did not find significant abnormalities of cholesterol, cholesterol lipoproteins, nor Apolipoprotein B. The only significant abnormality was the presence of a higher rate of hypertriglyceridemia in the retinal vein occlusion and primary chronic glaucoma groups in comparison with their control group. In these two affections, hypertriglyceridemia should be systematically researched and treated.

Apolipoproteins B↗
PubMed1985

Activation of energy expenditure in the rat by a new non-amphetaminic compound: the (4-chlorophenoxyacetate) N-methyl 3-hydroxymethyl piperidine, hydrochloride (PM 170).

The (4-chlorophenoxyacetate) N-methyl 3-hydroxymethyl piperidine, hydrochloride (PM 170), chemically unrelated to amphetamine, was studied in normal rats for any thermogenic effect. It was given in graded doses. After an acute treatment PM 170 increases energy expenditure by increasing resting oxygen consumption (VO2) and in the doses used, produced dose-related increases in VO2. Energy expenditure of rats treated for 16 days was chronically elevated, while body weight gain and food intake were reduced. It also stimulated mitochondrial oxygen consumption probably by partial uncoupling of respiration from ATP synthesis. The disruption of oxidative phosphorylation could partially explain the effect of this compound on resting metabolic rate.

Animals↗
PubMed1984

Stress and sucrose hyperphagia: role of endogenous opiates.

Two experimental situations induce hyperphagia in the rat: the cafeteria model and the tail-pinching model. In non-deprived rats which are offered for one hour a choice of 3 liquid cafeteria items in addition to ordinary chow and water, mild tail-pinching results in a preferential sucrose hyperphagia; naltrexone (2.5 mg/kg IP) suppresses this stress-induced hyperphagia; beta-endorphin (3 micrograms ICV) has the same effect. This apparent discrepancy is discussed: the antagonist may suppress the hyperphagia because it suppresses the reward provoked by the sucrose, the agonist because it makes it unnecessary.

Animals↗
PubMed1984

Difference in sensitivity of the mu and kappa systems in cafeteria rats.

A highly palatable diet (cafeteria diet) provokes an hyperphagia. The effects of Mu and Kappa opiate antagonists (Mu : Naltrexone 0.5 mg/Kg IP; Kappa Mr2266 0.5; 2.5; 10) and agonists (Mu Morphine 0.05; 0.1; 0.5; 2.5; Kappa Mr2033 0.5; 2.5) were studied on the nocturnal food intake of cafeteria rats and chow rats fed with monotonous food. At low doses Mu as well as Kappa antagonists do not modify the food intake of chow rats, but suppress the hyperphagia induced by the cafeteria diet. Kappa agonist provokes a decrease in food intake in chow and cafeteria rats while the Mu agonist at low doses suppresses the hyperphagia induced by cafeteria diet. The involvement of these two opioid systems in this type of hyperphagia is discussed.

Animals↗
PubMed1984

Effects of a very-low-calorie diet on adrenergic responsiveness in human adipose tissue.

Nineteen obese women were given a strictly-defined very-low-calorie diet for three weeks, and changes in adipose tissue lipolysis were studied using adrenergic drugs. The beta-receptor responsiveness was tested by isoprenaline. Before the diet, we found a negative relationship between basal value and isoprenaline-net effect on glycerol release; after the diet, its relationship disappeared, but the beta-stimulated level remained at a similar maximum. The alpha-receptor responsiveness was studied using clonidine, which significantly inhibits lipolysis; this effect was twice as high after the diet than before. Adrenaline-induced lipolysis was also studied; we found a dose-dependent response, and after a diet a negative linear relationship between basal and adrenaline net-lipolysis, so that adrenaline became antilipolytic for the high values of spontaneous lipolysis. We conclude that: (1) diet does not modify adipocyte-beta-receptor responsiveness, but it increases alpha-receptor responsiveness; (2) relationships between basal lipolysis and the lipolytic responsiveness of adrenergic receptors, which already exist with the spontaneous feeding, are enhanced by the hypocaloric diet, but in such a way that adipocyte-lipolysis remains within a given range; (3) we were unable to find any relationship between rate of weight loss and amplitude of adrenergic-receptor responsiveness.

Adipose Tissue↗
PubMed1983

Energy and nitrogen balances in 24 severely burned patients receiving 4 isocaloric diets of about 10 MJ/m2/day (2392 Kcalories/m2/day).

Twenty-four subjects with burns ranging from 25-70 per cent received for 12 days exclusively per os a series of 4 isocaloric diets of about 4000 Kcal--'normal', or hyperproteic, or hyperlipidic, or hyperglucidic according to a randomized schedule. Oxygen consumptions were measured at the end of each diet and nitrogen balance was determined every day. Though patients were not massively overfed there remained a positive energy gap. The nitrogen balance was found to be equilibrated on the whole but clearly positive with the hyperproteic diet and clearly negative with the hyperlipidic-normoproteic diet. Thus there is no rationale for the huge energy overfeeding classically used.

Adolescent↗
PubMed1983

Effects of an overfeeding regimen--the affective component of the sweet sensation.

In some isolated parts of North Africa, there persists an ancient Berber custom of imposing an overfeeding regimen on young girls before marriage, to achieve an obesity which is regarded as aesthetically pleasing. We have studied the effect of such a regimen, lasting 12--16 weeks, on blood lipids and on the affective reactions to sweet tastes in nine subjects. It is known that the pleasantness of alimentary cues i.e., the feeding behaviour, depends on the subject's nutritional state. Only three subjects gained weight (by 3,5 and 8 kg), in spite of the strong pressure to overeat. No change in plasma lipid concentrations were observed. Nevertheless, at the end of the regimen every subject showed a highly significant decrease in the rated pleasantness of sweet stimuli when they were tested fasting. However, the reduction in sweet pleasantness induced by ingestion of a 200 ml load of 1.4 M glucose solution was not changed by the overfeeding. Thus, pressure to overfeed can reduce hunger, as seen in the attractiveness of sweet foods in fasted subjects, without modifying glucose-induced satiety.

Adult↗
PubMed1982

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. Fourteen young healthy volunteers were studied: 1) at their spontaneous stable weight; 2) while losing weight rapidly on a calorically restricted diet; 3) and then at their stable new weight when consuming a refeeding diet. The calorie restricted diet resulted in decrease of VO2, and T3, and an increase of rT3; the refeeding diet resulted in values of VO2, T3, and rT3 intermediate between those of the spontaneous diet and those of the restricted diet. Another group of nine subjects were studied at their spontaneous caloric and proteic levels, comparing a diet containing only protein and carbohydrate with a diet containing only protein and fat. During the low carbohydrate diet rT3 increased and T3 decreased but they remained unchanged during the carbohydrate-rich diet. Thus neither the adipostatic hypothesis nor the carbohydrate hypothesis is sufficient alone to explain the observed changes in serum T3 and rT3.

Adolescent↗
PubMed1982

Tardy occurrence of adipocyte hyperplasia in cafeteria-fed rat.

White adipose tissue cellularity was studied in rats during a diet characterized by a free choice of highly palatable items. At the 8th wk the increase in adipose stores is due to hypertrophy. Between the 8th and 20th wk hypertrophy persists, but hyperplasia appears both in retroperitoneal and epididymal sites. The probable role of carbohydrate intake in the onset of hyperplasia is discussed.

Adipose Tissue↗