Effects of multiple cycles of weight loss and regain on the body weight regulatory system in rats.

We studied the effects of multiple cycles of weight loss and regain on the defended body weight in rats. Thirty-six male Wistar rats were divided into three weight-matched groups: weight cyclers ( = 18), ad libitum-fed controls ( = 9), and maturity controls ( = 9). Cyclers underwent four rounds of 20% weight loss from 50% caloric restriction, each cycle followed by recovery to stable plateau weight on ad libitum feeding.

Hyperosmolarity in the small intestine contributes to postprandial ghrelin suppression.

Plasma levels of the orexigenic hormone ghrelin are suppressed by meals with an efficacy dependent on their macronutrient composition. We hypothesized that heterogeneity in osmolarity among macronutrient classes contributes to these differences. In three studies, the impact of small intestinal hyperosmolarity was examined in Sprague-Dawley rats.

Ghrelin levels in young children with Prader-Willi syndrome.

Objective: To explore the hypothesis that high ghrelin levels contribute to obesity in Prader-Willi syndrome (PWS), we assessed whether the increased levels observed in older persons with PWS exist in very young children, before the onset of hyperphagia.

Study Design: We measured ghrelin levels in nine children with PWS (17-60 months of age) and eight healthy control subjects of equivalent body mass index (BMI), age, and sex.

Results: PWS and control groups had equivalent BMI (16.

Effect of aging on the response of ghrelin to acute weight loss.

Objectives: To determine whether the failure of the orexigenic hormone ghrelin to increase as it normally does with weight loss contributes to impaired weight recovery in older persons.

Design: Prospective diet intervention study.

Setting: University of Washington Medical Center from 2001 through 2005.

Human plasma ghrelin levels increase during a one-year exercise program.

Weight loss resulting from decreased caloric intake raises levels of the orexigenic hormone, ghrelin. Because ingested nutrients suppress ghrelin, increased ghrelin levels in hypophagic weight loss may result from decreased inhibitory input by ingested food, rather than from lost weight. We assessed whether ghrelin levels increase in response to exercise-induced weight loss without decreased caloric intake.