A double-blind placebo-controlled glucose challenge in bulimia nervosa: psychological effects

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Energy and macronutrient intake in bulimia nervosa

Energy deprivation and malnutrition are often thought to be key factors in the maintenance of bulimia nervosa (BN). Our review shows that it is unclear how much energy is actually available to BN patients' metabolism because the contribution of food consumed during binge eating is generally neglected. Also, there is little evidence for another key hypothesis that binge-eating episodes are triggered by carbohydrate craving. This study examined energy consumption and macronutrient composition of meals and binge-eating episodes in food diaries. Forty female BN patients, 40 female panic disorder (PD) patients, and 40 healthy women recorded their food intake while in their natural environment during two consecutive days. We did not find the expected evidence for chronic energy deprivation and malnutrition in BN patients. Also, there was no evidence that carbohydrate craving drives binge eating. The implications for models of BN and for treatments targeting eating behavior are discussed.

Polycystic ovary syndrome in adolescence and early adulthood

Polycystic ovaries and the associated syndrome are recognized as the most common cause of endocrine disturbances in adult women, but much less research has been performed to examine how polycystic ovary syndrome (PCOS) presents in girls and young women. Polycystic ovaries have been demonstrated in childhood, and there is evidence to show that even very young women may show symptoms and signs of the associated syndrome. Closer examination of younger populations (less-than-or-eq, slant 25 years of age), and in particular, studies of girls during the transition from puberty into early adulthood (adolescence), may provide new insights into the pathogenesis and natural history of polycystic ovaries and PCOS, and may indicate whether polycystic ovaries could potentially be considered as a marker for health screening. Consideration should be given to the management of girls and young women with polycystic ovaries and PCOS as this group may have different needs and health risks compared with older women.

Polycystic ovaries and eating disorders: Are they related?

A cross-sectional observational study was used to investigate the reported association between polycystic ovarian syndrome and bulimia nervosa in a group of young, post-menarcheal women in the normal population. Volunteers aged 18-25 years were recruited from two universities and two general practice surgeries in Oxford. A total of 230 women completed an interviewer-based eating disorder examination, which was used to diagnose bulimia nervosa and its variants, and to assess eating behaviour. Transabdominal ultrasound was used to diagnose the presence or absence of polycystic ovaries. Symptoms of polycystic ovarian syndrome were assessed using menstrual history, anthropometric measurements, clinical observation of acne and hirsutism, and biochemical analysis of a fasting blood sample. A total of 30% of all participants described episodes of overeating and 4% had used extreme methods of weight control. Two women were diagnosed with bulimia nervosa, and five women with binge-eating disorder; however, these diagnoses were not associated with polycystic ovaries. Scores for dieting and overall eating disorder symptoms in the polycystic ovary groups were not significantly higher than those for women with normal ovaries, and therefore the suggestion that polycystic ovaries predispose towards the development of eating disorders is not supported by this study.

Introduction and commentary to: M.I. Mityushov (1954) "Conditioned reflex secretion of insulin"

Recent research on the role of classical conditioning in homeostatic regulation (Dworkin, 1993; Siegel, Krank & Hinson, 1987) has underscored the potential importance of the work of earlier Eastern-European work on physiological conditioning. The present article is a translation and discussion of a paper on blood glucose conditioning, first published in 1954 by the Russian physiologist M.I. Mityushov. Mityushov was able to demonstrate conditioned hypoglycemia in humans and dogs after using an injection procedure as the CS and intravenous glucose as the UCS. The translation is preceded by a general introduction and followed by a reanalysis and discussion of Mityushov's results.

Plasma amino acid ratios related to brain serotonin synthesis in response to food intake in bulimia nervosa

Fifteen bulimic women (BN) and 19 healthy female controls (CO) were studied. The subjects were cross-over treated with either fluoxetine (FXT) or placebo during 4 days. They received, in randomized order, a breakfast containing pure carbohydrate (CHO) or a protein-rich (PROT) breakfast following day 3 and 4 of each treatment period. Twenty-nine different food items were offered for lunch. The fasting serum glucose and insulin concentrations and the fasting plasma tryptophan (Trp)/large neutral amino acid (LNAA) ratio were slightly higher in BN. The changes of these metabolic parameters in response to a CHO or PROT breakfast were similar in both groups. Across breakfast type, the plasma (Trp)/(LNAA) ratio at 120 min after breakfast was higher in BN. Total caloric intake at lunchtime was less in BN. In CO, less carbohydrate was selected at lunchtime following the CHO breakfast, an effect that was abolished by FXT. Breakfast type or FXT did not have any apparent effect on food intake at lunchtime in BN. This might indicate that bulimic subjects are less sensitive to serotoninergic stimuli than control subjects.