Premium
Caloric Restriction‐Induced Decreases in Dopamine Receptor Availability are Associated with Leptin Concentration
Author(s) -
Dunn Julia P.,
Abumrad Naji N.,
Kessler Robert M.,
Patterson Bruce W.,
Li Rui,
MarksShulman Pamela,
Tamboli Robyn A.
Publication year - 2017
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1002/oby.22023
Subject(s) - leptin , medicine , endocrinology , putamen , insulin , ghrelin , radioligand , calorie restriction , weight loss , obesity , receptor
Objective It has been previously reported that early after Roux‐en‐Y‐gastric bypass, dopamine (DA) type 2 and 3 receptor (D2/3R) binding potential (BP ND ) was decreased from preoperative levels. The current study aimed to determine whether calorie restriction without weight loss modifies D2/3R BP ND and whether such changes are explained by neuroendocrine regulation. Methods Fifteen females with obesity (BMI = 39 ± 6 kg/m 2 ) were studied before and after ∼10 days of a very‐low‐calorie‐diet (VLCD). Outcome measures included fasting insulin, leptin, acyl ghrelin, and glucose, and insulin sensitivity and disposition index were estimated using the oral‐minimal model (OMM) method. Participants underwent positron emission tomography scanning with the displaceable radioligand [ 18 F]fallypride to estimate available regional D2/3R levels. Regions of interest included the caudate, putamen, ventral striatum, hypothalamus, and substantia nigra (SN). Results With the VLCD, weight decreased slightly (−3 kg). Insulin, glucose, and leptin decreased significantly, but there was no change in acyl ghrelin or measures from OMM. SN D2/3R BP ND decreased significantly, with trends toward decreased levels in the remaining regions. The decrease in leptin concentration strongly predicted the change in D2/3R BP ND in all regions (all P ≤ 0.004). Conclusions In obesity, reductions in regional D2/3R availability after VLCD are suggestive of increased endogenous DA competing with the radioligand. Changes in regional D2/3R availability were associated with decreases in leptin concentrations that occurred before clinically significant weight loss.