The anorectic effect of fenfluramine is influenced by sex and stage of the estrous cycle in rats

The controls of food intake differ in male and female rats. Daily food intake is typically greater in male rats, relative to female rats, and a decrease in food intake, coincident with the estrous stage of the ovarian reproductive cycle, is well documented in female rats. This estrous-related decrea...

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Published in:American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2005-06, Vol.57 (6), p.R1486-R1491
Main Authors: ECKEL, Lisa A, RIVERA, Heidi M, ATCHLEY, Deann P. D
Format: Article
Language:English
Subjects:
Animal reproduction
Biological and medical sciences
Drugs
Effects
Fundamental and applied biological sciences. Psychology
Mammalian reproduction. General aspects
Olfactory system and olfaction. Gustatory system and gustation
Rodents
Sexes
Vertebrates: nervous system and sense organs
Vertebrates: reproduction
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Summary:The controls of food intake differ in male and female rats. Daily food intake is typically greater in male rats, relative to female rats, and a decrease in food intake, coincident with the estrous stage of the ovarian reproductive cycle, is well documented in female rats. This estrous-related decrease in food intake has been attributed to a transient increase in the female rat's sensitivity to satiety signals generated during feeding bouts. Here, we investigated whether sex or stage of the estrous cycle modulate the satiety signal generated by fenfluramine, a potent serotonin (5-HT) releasing agent. To examine this hypothesis, food intake was monitored in male, diestrous female, and estrous female rats after intraperitoneal injections of 0, 0.25, and 1.0 mg/kg D-fenfluramine. The lower dose of fenfluramine decreased food intake only in diestrous and estrous females, suggesting that the minimally effective anorectic dose of fenfluramine is lower in female rats, relative to male rats. Although the larger dose of fenfluramine decreased food intake in both sexes, the duration of anorexia was greater in diestrous and estrous female rats, relative to male rats. Moreover, the magnitude of the anorectic effect of the larger dose of fenfluramine was greatest in estrous rats, intermediate in diestrous rats, and least in male rats. Thus our findings indicate that the anorectic effect of fenfluramine is modulated by gonadal hormone status. [PUBLICATION ABSTRACT]
ISSN:0363-6119
1522-1490