Plain language summary
It is thought that the neurotransmitter serotonin may play a role in the development of obesity, due to its effects on satiety, nutrient selection, and the reward system. The aim of this study was to measure the effects of a selective serotonin reuptake inhibitor (SSRI) on the hormones prolactin, corticotropin and cortisol. In this double-blind, placebo-controlled trial, a single intravenous dose of the SSRI clomipramine (CMI) was given to 12 obese and 6 non-obese women, and their hormone levels measured before and after. Six of the obese women went on to lose between 8-12% of their body weight and their response to CMI was measured again. No difference was found in the baseline levels of hormones between the non-obese, obese before and after weight loss. Levels of prolactin, corticotropin and cortisol rose significantly across all groups after administration of CMI, with the corticotropin and cortisol responses being greater in the obese group. The peak cortisol value was around 30% greater in the obese compared to the non-obese group. Weight loss did not seem to affect the hormonal response to CMI. The results of this study support the assumption that the hypothalamic pituitary adrenal axis (HPA) in obese women is unusually sensitive to serotonin and that losing weight does not normalise this.
Abstract
Serotoninergic control of food intake has been shown to be abnormal in obese persons with a decrease in serotoninergic tone. The neuroendocrine effects of intravenous I.V. administration of clomipramine (CMI), a serotonin uptake inhibitor, were studied in normal-weight (n=7) and obese subjects before (n=12) and after (n=6) dietary restriction. Under double-blind, placebo-controlled conditions, a single 12.5 mg dose of CMI was administered. There was no difference in baseline values of prolactin (PRL), corticotropin (ACTH) and cortisol in non-obese controls, obese before and obese after weight loss. CMI led to significant increases of PRL, ACTH, and cortisol concentrations in the controls as well as the obese group. The ACTH and cortisol responses to CMI in obese subjects were somewhat greater than the responses in normal-weight subjects. The area under the curve AUC for ACTH after clomipramine was 6202 +/- 976 pg/ml x 150 minutes for tile obese before weight loss and 3274 +/- 512 pg/ml x 150 minutes for the controls and the difference was significant at the level of p=0.052. The cortisol peak value after clomipramine was 163.71 +/- 14.31 ng/ml in the non-obese and 214.66 +/- 12.59 ng/ml in the obese (p=0.025). However, there was no difference in the obese subjects before and after weight loss. These data support the assumption that obese women have an abnormal sensitivity to the serotoninergic control of the hypothalamic pituitary adrenal axis (HPA), and that a mild weight loss does not significantly modify their serotoninergic tone.
Methodological quality
Jadad score
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2
Allocation concealment
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Yes
