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Biomedical subjects

N Orthen-Gambill

Publications and source records attributed to N Orthen-Gambill.

8 recordsLinked to original sources
PubMed1992

FMH-induced decrease in central histamine levels produces increased feeding and body weight in rats.

The present study tested the long-term effects of the histamine (H) synthesis inhibitor alpha-fluoromethylhistidine (FMH) on feeding and body weight in rats. FMH (administered via 2-week osmotic minipumps) increased feeding significantly throughout the test period. Body weights were also significantly increased toward the end of the test period. Hypothalamic H assays, performed at the end of the study, confirmed that FMH-treated rats had significantly lower H levels than controls. In general, the results suggest that H activity and feeding are inversely related.

Animals↗
PubMed1990

Differential effects of psychotropic drugs on feeding in rats: is histamine blockade involved?

The present animal studies tested the hypothesis that drug-induced blockade of histamine-1 receptors leads to appetite stimulation. Test agents included the antipsychotic promazine which has very potent antihistaminic effects, as well as the antipsychotic haloperidol and the antidepressant desipramine which both have negligible antihistaminic effects. In support of the hypothesis, significant appetite stimulation occurred only with promazine, while the other two test agents did not increase feeding, and even produced some suppression in food intake.

Animals↗
PubMed1988

Antihistaminic drugs increase feeding, while histidine suppresses feeding in rats.

The present studies tested the hypothesis that histamine blockade stimulates appetite, while increases in histamine levels suppress appetite. Results show that the classical antihistamines cyproheptadine and promethazine both produced significant and long-lasting increases in food intake. Pronounced appetite stimulation was also seen following the administration of doxepin, the most potent antihistamine among the antidepressants. In contrast, administration of the histamine precursor histidine produced a profound suppression in food intake. The results thus suggest that an inverse relationship may exist between histamine and food intake.

Animal Feed↗
PubMed1985

Sucrose intake unaffected by fenfluramine but suppressed by amphetamine administration.

The present study examined the acute effects of the anorectic agents, fenfluramine and amphetamine, on nutrient selection in male Sprague-Dawley rats. One group of animals received continuous access to both granulated sucrose and Purina chow (presented in separate cups), while the other group received only Purina chow. Four doses of fenfluramine (0, 1.5, 3.0, 6.0 mg/kg) and four doses of amphetamine (0, 0.5, 1.0, 2.0 mg/kg) were tested. Injections were given at the beginning of the feeding period, and nutrient intakes were measured at 2, 4, and 8 h postinjection. While both fenfluramine and amphetamine resulted in similar overall decreases in caloric intakes, the two drugs produced different effects on nutrient selection. Following fenfluramine administration, sucrose intakes remained relatively unaffected, while Purina chow intakes showed pronounced suppression. In contrast, amphetamine administration resulted in a more equal suppression of both sucrose and Purina chow intakes. While the overall decreases in food intake seen with fenfluramine and amphetamine may be linked to changes in central neurotransmitter levels, the sparing of sucrose consumption observed with fenfluramine may also involve drug-induced changes in peripheral metabolism.

Amphetamine↗
PubMed1982

Differential effects of amphetamine and fenfluramine on dietary self-selection in rats.

Daily caloric intakes and dietary self-selection of the three macronutrients, protein, fat and carbohydrate were examined in female rats following administration of d-amphetamine sulfate (0.0, 0.5, 1.0 and 2.0 mg/kg, IP) or fenfluramine hydrochloride (0.0, 1.5, 3.0 and 6.0 mg/kg, IP). Animals were maintained on ground Purina Chow or one of two self-selection regimes, one with a high-caloric fat ration (7.85 kcal/g) and the other with a fat ration isocaloric to the carbohydrate and protein rations (3.76 kcal/g). Animals received drug injections at the beginning of a daily 8-hour feeding period with nutrient intakes measured at 2, 4 and 8 hrs following injections. While both amphetamine and fenfluramine lef to dose-related decreases in total caloric intakes, the two drugs resulted in different temporal patterns of feeding. Amphetamine produced its greatest effect on caloric intake during the first 2 hours of the feeding period, whereas fenfluramine suppressed caloric intake equivalently across the 8-hour feeding period. The two anorectic drugs also led to different patterns of nutrient choice. When animals were given the high-caloric fat ration, amphetamine selectively decreased fat intake while fenfluramine produced decreases in both protein and fat intakes, sparing carbohydrate intake. In contrast, when animals were given the isocaloric fat ration, amphetamine resulted in a general suppression of nutrient intakes while fenfluramine led to a sustained decrease in fat intake with a relative sparing of protein and carbohydrate consumption.

Amphetamine↗
PubMed1982

Differential effects of sucrose, fructose and glucose on carbohydrate-induced obesity in rats.

Caloric intakes, body weights, plasma glucose levels and glucose tolerance were examined in male Sprague-Dawley rats given a single standard diet or the standard diet and one of four sources of sugar: 1) a 32% glucose solution, 2) a 32 % fructose solution, 3) a 32% sucrose solution or 4) granulated sucrose. After 50 days, blood was collected from fasted animals for analyses of serum glucose, triglycerides and insulin levels. Livers, kidneys, epididymal and retroperitoneal fat depots and intrascapular brown adipose tissue (BAT) were removed and weighed. Animals given sugar solutions and the standard diet consumed significantly more calories, gained more weight and had significantly more retroperitoneal fat than controls given only the standard diet. Although rats given granulated sucrose and the standard diet did not eat more, they did gain significantly more weight per kilocalorie consumed and had more retroperitoneal fat than controls. Rats given the sucrose solution had significantly more BAT than controls or rats given the fructose solution or granulated sucrose. Rats receiving glucose had significantly more BAT than controls. Access to the fructose or sucrose solutions led to a decreased ability to tolerate an oral glucose load. Animals given fructose had significantly greater serum triglyceride levels than controls or rats given the glucose or sucrose solutions.

Adipose Tissue↗