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This Article Full Text Full Text (PDF) All Versions of this Article: 290/2/E218    most recent 00156.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Kok, P. Articles by Pijl, H. Search for Related Content PubMed PubMed Citation Articles by Kok, P. Articles by Pijl, H.

Increased circadian prolactin release is blunted after body weight loss in obese premenopausal women

Departments of ¹General Internal Medicine, ²Endocrinology and Metabolic Diseases, and ³Clinical Chemistry, Leiden University Medical Center, and ⁴Center for Human Drug Research, Leiden University Medical Center, Leiden, The Netherlands

Submitted 8 April 2005 ; accepted in final form 3 September 2005

We recently showed that prolactin (PRL) release is considerably enhanced in obese women in proportion to the size of their visceral fat mass. PRL release is inhibited by dopamine 2 receptor (D2R) activation, and dietary restriction/weight loss are associated with increased dopaminergic signaling in animals. Therefore, we hypothesized that enhanced PRL release in obese humans would be reversed by weight loss. To evaluate this postulate, we measured 24-h plasma PRL concentrations at 10-min intervals in 11 obese premenopausal women (BMI 33.3 ± 0.7 kg/m²) before and after weight loss (50% reduction of overweight/15% absolute weight loss, using a very low-calorie diet) in the follicular phase of their menstrual cycle. The 24-h PRL concentration profiles were analyzed by a peak detection program (Cluster) and a wave form-independent deconvolution technique (Pulse). Spontaneous 24-h PRL secretion was significantly reduced in obese women [mean daily release, before 128 ± 24 vs. after weight loss 110 ± 17 µg/liter distribution volume (Vdl)^–1 x 24 h, P = 0.05]. Body weight loss particularly blunted PRL secretory burst mass (Pulse area, before 230 ± 28 vs. after weight loss 221 ± 31 µg/Vdl^–1 x 24 h, P = 0.03), whereas burst frequency was unaffected (no. of pulses, before 11 ± 1 vs. after weight loss 12 ± 1 n/24 h, P = 0.69). Thus elevated PRL secretion rate in obese women is significantly reduced after loss of 50% of overweight. We speculate that amelioration of deficit D2R-mediated neurotransmission and/or diminutions of circulating leptin/estrogen levels might be involved in the physiology of this phenomenon.

caloric restriction; estrogen; dopamine; leptin