The effect of moderate weight loss on overnight growth hormone and cortisol secretion in healthy female volunteers

Dairy food consumption and meal-induced cortisol response interacted to influence weight loss in overweight women undergoing a 12-week, meal-controlled, weight loss intervention

Dairy food enhances weight loss in animal models, possibly by modifying the metabolic effects of cortisol. This study determined in overweight women (ages 20.0-45.9 y; n = 51) whether including dairy food in an energy-restricted diet affects cortisol concentrations and whether differences in provoked cortisol explain the magnitude of weight loss. Women received either an adequate amount of dairy food (AD), the equivalent of ≥711 mL/d milk, or a low amount of dairy food (LD), the equivalent to ≤238 mL/d milk, in a 12-wk, energy-restricted dietary intervention. Participants were tested in a 12-h laboratory visit, which included 2 standard meals and a dinner buffet that was consumed ad libitum. Salivary cortisol was measured from waking to bedtime. Energy restriction increased (P ≤ 0.04) the minimum and decreased (P ≤ 0.02) the diurnal amplitude in the salivary cortisol concentration from baseline to postintervention. Energy restriction enhanced the dinner meal-stimulated salivary cortisol response (DMR) (P ≤ 0.02) but only in the LD group. Compared with the LD treatment, the AD treatment induced (P ≤ 0.04) greater reductions in body weight and fat, but only in women characterized as having a baseline DMR (responders) (n = 26); weight and fat lost in the AD and LD groups were similar in nonresponders (n = 25). Overall, energy restriction dampened diurnal salivary cortisol fluctuations [symptomatic of hypothalamic-pituitary-adrenal (HPA) axis dysfunction] and enhanced dinner meal-stimulated salivary cortisol concentrations. The AD treatment prevented the latter. Furthermore, certain phenotypic markers of HPA axis function may help to expose the weight-reducing effects of consuming dairy food.

The Effect of Exercise on Leptin, Insulin, Cortisol and Lipid Profiles in Obese Children

This prospective, randomized study investigated the effect of exercise on leptin, insulin, cortisol and lipid profiles in obese children. A total of 40 obese boys aged 10-12 years with a body mass index (BMI) ≥ 30 kg/m2 were randomly separated into an exercise group ( n = 20) that underwent a 12-week aerobic exercise programme and a non-exercise (control) group ( n = 20). The BMI, low-density lipoprotein, cortisol, leptin and insulin levels were significantly lower in the exercise group after 12 weeks compared with baseline values, whereas high-density lipoprotein levels were significantly higher. In contrast, in the control group, low-density lipoprotein, cortisol and leptin levels were significantly higher after 12 weeks compared with baseline values while high-density lipoprotein levels were significantly lower. These findings indicate the importance of regular exercise in the regulation of body weight and protection against cardiovascular risk factors in obese children.

Bone mineral metabolism in diet-induced amenorrhea

Spinal bone density of 41 girls with diet-induced amenorrhea (DA) was compared with that of the density of 22 subjects with premature ovarian failure (POF) of comparable age. The Z score values, as well as the estradiol levels, were not significantly different in the two groups. The duration of amenorrhea was significantly correlated to bone mass density in the DA population, especially when considering subjects with amenorrhea that had lasted longer than 20 months. A similar correlation between weight loss and BMD was evident. Although estradiol concentrations did not seem to be correlated to the Z score, FT3 and cortisol values exhibited, respectively, a negative and a positive correlation with spinal density. Cortisol seemed to act precociously, whereas FT3 acted later than cortisol.

The effect of moderate weight loss on overnight melatonin secretion

Overnight plasma melatonin level was measured in ten healthy women before and after a 4300 kJ (1000 kcal) diet in which they lost an average 3.1 kg. This weight loss did not significantly alter melatonin levels.

The effects of gepirone on neuroendocrine function and temperature in humans

The effects of the selective 5-HT1A receptor agonist gepirone (10 and 20 mg orally) on neuroendocrine function and temperature were assessed using a single-blind cross-over design in 12 healthy male volunteers. Gepirone significantly increased plasma levels of ACTH, beta-endorphin, cortisol, prolactin and growth hormone. Following gepirone there was a significant decrease in body temperature and moderate increases in subjective reports of light-headedness, nausea and drowsiness. Our results are consistent with studies in rodents suggesting that 5-HT1A receptor agonists increase ACTH and prolactin secretion and decrease body temperature. Further investigations are needed to determine if the neuroendocrine and temperature effects of gepirone in humans are mediated by 5-HT1A receptors.

Effect of moderate weight loss on prolactin secretion in normal female volunteers

Sleep-related prolactin secretion and prolactin responses to the infusion of low doses of the dopamine antagonist, metoclopramide, and thyrotropin-releasing hormone were measured in 11 female volunteers before and after undertaking a diet in which they lost a mean of 3.1 kg in weight in 3 weeks. No effect of weight loss on these measures was found, but there was a significant, although modest, reduction in fasting plasma tryptophan concentration without any change in the concentration of competing amino acids.