Impaired cholecystokinin secretion in bulimia nervosa

Reduced serum cholecystokinin and increase in body fat during oral contraception

This investigation was undertaken to explore a possible role of the "satiety peptide" cholecystokinin and some other gastrointestinal hormones for changes in appetite and weight during oral contraception. Ten young healthy women attending a youth health care center for contraceptive counseling volunteered for the study. A standardized meal test was used for recordings of appetite and gastrointestinal hormone response before and after 5 months of treatment with a monophasic combined oral contraceptive. Body fat was calculated from measurements of skin-fold thickness. Oral contraceptives caused a suppression of basal levels of serum cholecystokinin, which was correlated to an increase in body fat. Meal-related response of cholecystokinin and appetite were not affected. Serum levels of gastrin and insulin were also unchanged, whereas triglycerides and postprandial glucose levels were elevated. The results suggest a role of cholecystokinin in regulation of body composition. Cholecystokinin stimulates the release of insulin and stimulates lipolysis in adipose tissue. Reduced cholecystokinin levels may, therefore, be related to mild impairment of glucose tolerance and promote body fat storage during oral contraception.

T-lymphocyte concentrations of cholecystokinin-8 and beta-endorphin in eating disorders: II. Bulimia nervosa

Concentrations of cholecystokinin-8 (CCK-8) and beta-endorphin (beta-EP) in T-lymphocytes of 26 women with bulimia nervosa (BN) and in 26 age- and sex-matched healthy comparison subjects were measured. Ten patients were then treated with 300 mg/day of fluvoxamine, p.o., and five patients were treated with 300 mg/day of amineptine, p.o., for 4 months. Concentrations of the two peptides were measured again after 1, 2, and 4 months of therapy. Basal CCK-8 values were significantly lower in patients than in healthy subjects. During fluvoxamine therapy, CCK-8 values increased, reaching normal levels by month 4 of treatment. No such increase occurred during amineptine therapy. Baseline beta-EP values were normal in the bulimic patients but had declined by month 4 of fluvoxamine therapy.

Serotonin and bulimia nervosa

Serotonin (5HT) is one of several neuromodulators of feeding. Experimentally reducing 5HT activity in animals increases food intake, while increasing 5HT activity has the opposite effect. Studies suggest that women with bulimia nervosa show signs of reduced 5HT activity, which may be related to binge eating. Data supporting the theory that reduced central nervous system 5HT activity may play a role in the pathophysiology of bulimia nervosa is reviewed. Disturbances of 5HT activity and the relationship to other psychopathology in bulimia nervosa, such as depression, substance abuse, and impulsivity, are also reviewed.

Role of neuropeptides in the regulation of feeding behavior: a review of cholecystokinin, bombesin, neuropeptide Y, and galanin

The purpose of this report is to provide a review of four peptides (cholecystokinin, bombesin, neuropeptide Y, galanin) and their role in feeding behavior. Cholecystokinin (CCK) and bombesin (BBS) are considered satiety peptides, and neuropeptide Y (NPY) and galanin (GAL) have been proposed as appetite peptides. For the purposes of this review, satiety refers to the physiological cessation of feeding, and appetite refers to the drive to eat and exists in gradations.

Reduced serum cholecystokinin response to food intake in female athletes

Strenuous training in women has been shown to cause menstrual dysfunction and decreased bone mineral density. These endocrine and metabolic complications are associated with an insufficient dietary intake and decreased body fat content in female athletes. The present investigation was undertaken to study serum levels of cholecystokinin (CCK), insulin, gastrin, and cortisol in 14 female long-distance runners and 15 sex- and age-matched control subjects during intake of a standardized meal (500 kcal). The athletes showed a decreased response of the "satiety peptide" CCK to the meal and reported increased hunger compared with the control group. Meal-related insulin response was also decreased in the athletes, whereas gastrin levels were comparable to those of controls. Basal levels of glucose were increased in the athletes, but there was no difference in postprandial levels between the groups. Cortisol levels were clearly elevated in the female runners. We conclude that insufficient food intake in female athletes cannot be explained by increased CCK secretion and satiety. Since the athletes reported a larger caloric intake of a normal daily breakfast than the control subjects, the decreased CCK response may instead be explained by an adaptation to increased food intake. The decreased meal-related insulin response may be a reflection of increased insulin sensitivity as an adaptation to physical exercise. However, an impaired peptide secretion cannot be excluded. The role of elevated cortisol levels in the gastrointestinal hormone response needs further investigation.

Satiety and cholecystokinin

The effect of a fat and protein rich test meal of 800 kcal on subjective satiety ratings and on plasma cholecystokinin (CCK) 8-S was studied in 18 acutely ill patients with anorexia nervosa, 11 former anorectic patients, who were weight recovered for at least 4 years, and in 25 healthy young women. Eleven normal weight patients with bulimia nervosa were studied in the same experiment. Satiety ratings were significantly elevated in acutely ill anorectic and bulimic patients. CCK 8-S values were significantly stimulated by the test meal in all groups except from the bulimic group. Anorectic patients and weight recovered anorectics had normal values before and after the test meal. Bulimic patients had significantly lower values. These data suggest that CCK 8-S is not involved in the regulation of short-term satiety in anorexia and bulimia nervosa.

Biological actions of cholecystokinin

Cholecystokinin (CCK) has emerged as an important mammalian neuropeptide, localized in peripheral organs and in the central nervous system. This review presents an overview of the molecular aspects of CCK peptides and CCK receptors, the anatomical distribution of CCK, the neurophysiological actions of CCK, release of CCK and effects of CCK on release of other neurotransmitters, and the actions of CCK on digestion, feeding, cardiovascular function, respiratory function, neurotoxicity and seizures, cancer cell proliferation, analgesia, sleep, sexual and reproductive behaviors, memory, anxiety, and dopamine-mediated exploratory and rewarded behaviors. Human clinical studies of CCK in feeding disorders and panic disorders are described. New findings are presented on potent, nonpeptide CCK antagonists, selective for the two CCK receptor subtypes, which demonstrate that endogenous CCK has biologically important effects on physiology and behavior.

Cholecystokinin in human cerebrospinal fluid: concentrations, dynamics, molecular forms and relationship to fasting and feeding in health, depression and alcoholism

Very little is known about the physiologic significance of the gut-brain hormone cholecystokinin (CCK) in the human central nervous system, although the hormone has been hypothesized to be involved in the regulation of both appetite and anxiety. We continuously collected lumbar cerebrospinal fluid (CSF) via indwelling subarachnoid catheters in ten normal volunteers, ten patients with major depression and five abstinent alcoholic humans, while fasting and after eating. Five other healthy subjects were fasted throughout the experiment. We quantified CSF immunoreactive cholecystokinin (IR-CCK) and glucose concentrations at 10-min intervals from 11.00 to 17.00 h. No difference in CSF IR-CCK concentration, half-life or rhythm was observed between normal volunteers and either depressed or alcoholic patients. Fasting CSF IR-CCK concentrations were 1.3 +/- 0.18, 1.3 +/- 0.21 and 1.2 +/- 0.21 fmol/ml (mean +/- S.E.M.) in normal volunteers, depressed patients and alcoholic patients, respectively. After eating, CSF IR-CCK concentrations rose to 1.5 +/- 0.21, 1.5 +/- 0.24 and 1.4 +/- 0.26 fmol/ml, respectively. Normal volunteers who did not eat had similar basal CSF IR-CCK concentrations (1.1 +/- 0.1 fmol/ml) which similarly rose to 1.4 +/- 0.13 fmol/ml during the sampling interval. In contrast, CSF glucose concentrations rose only in the subjects who ate, beginning to rise after about 1 h and remaining elevated for at least 3 h after eating. These data suggest the existence of a diurnal rhythm of IR-CCK release into CSF, as opposed to a response to feeding. The disappearance half-time of CCK in human CSF is less than 13 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in plasma cholecystokinin concentrations after oral glucose tolerance test in anorexia nervosa before and after therapy

There is considerable evidence that the gastrointestinal hormone cholecystokinin (CCK) induces satiety and reduces food intake in both animals and humans. Impaired CCK secretion was recently reported in patients with bulimia nervosa (BN) in whom plasma CCK responses to a standardized mixed-liquid meal were significantly lower than in controls. The present study was undertaken to determine whether CCK levels were abnormal in another relatively common eating disorder, anorexia nervosa (AN), before and after therapy and to investigate the relationship to the abnormal eating behavior. Plasma CCK, serum glucose, and immunoreactive insulin (IRI) responses to a 50-g oral glucose load were measured in 13 women with AN and in nine normal sex- and age-matched controls. The AN patients were all hospitalized during treatment; following partial restoration of body weight, the tests were repeated. Initial body weights were 70.8% +/- 1.8% (mean +/- SEM) of ideal body weight (IBW), and following partial restoration were 84.3% +/- 1.4%. Body weights in normal controls were 96.3% +/- 2.1% of IBW. Initial basal CCK concentrations in the AN patients before nutritional and cognitive behavioral therapy were significantly greater than those in controls (P < .01). After partial restoration of body weight, basal CCK concentration in AN patients approached that of control subjects. When AN patients were given a glucose load before therapy, the change in CCK response was diminished when compared with that of controls. However, CCK responses to the glucose load in AN patients following therapy were similar to those of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity-induced anorexia in rats does not affect hypothalamic neuropeptide gene expression chronically

Hypothalamic neuropeptides are thought to contribute to the pathophysiology of eating disorders. In an animal model with chronic abnormalities of energy expenditure, appetitive behavior, and body weight, without acute food restriction, we found alterations in peripheral levels of adrenocorticotropic hormone and corticosterone, but no alterations in the expression of neuropeptides genes that are known to regulate ingestive behavior and food intake acutely. Our data suggest that activation of hypothalamic-pituitary-adrenal function in activity anorexia may not be due to increased transcription of corticotropin-releasing hormone gene, but might be related to posttranscriptional events or to other neuropeptides, such as arginine vasopressin. Furthermore, we suggest that abnormalities in neuropeptides observed in eating disorders may be caused by acute food restriction, rather than by chronic hyperactivity, anorexia, and low weight.

Psychopharmacogenetic aspects of Prader-Willi syndrome

The study of genes, drugs, and behavior in three male adolescents with Prader-Willi syndrome (PWS) revealed a clinical profile that raises questions about the indications for neuroleptic and appetite-suppressing medications in this condition. Evidence of the inadvisability of neuroleptic medication and of the pathophysiology of PWS has led to a remarkable control of violent outbursts and hyperphagia by carbamazepine in one patient afflicted with both PWS and Klinefelter's syndrome. Testosterone and behavioral therapy proved to be useful in the management of two patients. The present observations, which are supported by recent advances in the pathophysiology of satiety, suggest that PWS should be understood as a metabolic disorder and subjected to psychopharmacogenetic study.

Bulimia nervosa in Hong Kong Chinese patients

In contrast to the West, bulimic disorders are rarer than anorexia nervosa in Hong Kong. Four female normal-weight bulimic patients with mostly typical clinical features and conspicuous morbidity are reported. The case histories support the hypothesis that binge-eating is used to regulate unpleasant effect.

Relationship of satiety to postprandial glycaemic, insulin and cholecystokinin responses

The effect of plasma glucose on satiety and the capacity of carbohydrates to stimulate cholecystokinin (CCK) remain unclear. The aim of this study was to test the hypothesis that the magnitude of the postprandial plasma glucose and insulin response is inversely related to the CCK response and to subjective satiety. Seven healthy, male volunteers consumed equal carbohydrate portions (0.5 g/kg body weight) of six test meals (Rice Bubbles, Sustain, Vita-Brits, All-Bran, porridge and white bread) in random order after an overnight fast. An egg and bacon meal was consumed as a non-carbohydrate control providing 0.5 g protein/kg body weight. Serum CCK, plasma glucose and insulin and subjective satiety (measured by a rating scale) were assessed over 3 h and quantified using the glycaemic index (GI), insulin index (II), the peak satiety score and area under the incremental curve (AUC). The observed GIs (mean +/- SE) ranged from 42.5 +/- 2.6 for All-Bran to 116.2 +/- 11.4 for Rice Bubbles, using white bread as the reference food (GI = 100). Peak satiety scores varied eightfold from 0.21 +/- 0.4 for Sustain to 1.64 +/- 0.4 for All-Bran. Significant inverse relationships were observed between the peak satiety score and both the glycaemic and insulin index of the seven meals (r = -0.916, p less than 0.001 and r = -0.926, p less than 0.001). A direct relationship was observed between satiety (AUC) and the CCK response (AUC) (r = 0.73 p less than 0.01). The results suggest that glycaemic and insulin responses to carbohydrate foods are inversely proportional to the CCK response and satiety.

Cholecystokinin, vasoactive intestinal peptide and peptide histidine methionine responses to feeding in anorexia nervosa

Anorexia nervosa (AN) is a syndrome of unknown cause characterized by voluntary starvation. Cholecystokinin has been implicated as a neuroendocrine regulatory factor in control of satiety. Relatively little information is known about gastrointestinal hormone responses to feeding in subjects with anorexia nervosa. In the present studies, we examine fasting and postprandial levels of cholecystokinin (CCK), vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) in anorexia nervosa subjects and in control individuals. Results of these studies indicate that plasma CCK response to a liquid meal (Ensure Plus) in untreated AN subjects was distinctly different from that observed in healthy controls, both in terms of temporal pattern of peptide released and the amount of CCK secreted into the circulation. Peak levels of CCK release occurred at 30 min following meal ingestion in AN patients and at 60 min in control subjects. Integrated CCK release in untreated AN patients was approximately twice that measured in control individuals. Renutrition therapy was associated with reversion of the pattern of CCK release to that observed in control subjects. Plasma VIP levels were unchanged following meal ingestion in both control and anorexic subjects. In contrast, PHM levels in AN subjects were significantly greater than that observed in control individuals. The pattern of PHM release following liquid meal ingestion was similar to that observed with plasma CCK; namely, peak release of peptide was observed at 30 min which was significantly greater than corresponding control values (P less than 0.05). In conclusion, these results demonstrate distinctive differences in plasma CCK and PHM levels in response to feeding in AN subjects when compared to control individuals. These findings suggest that the earlier and greater rise in plasma CCK levels in AN subjects following meal ingestion may contribute to the abnormal sensation of satiety in this condition.

Eating behavior in eating disorders: response to preloads

Eating behavior in eating-disordered subjects was investigated by recording food intake and subjective ratings following three preloads differing in calories, weight and connotation. Subjects were patients with a DSM-IIIR diagnosis of anorexia nervosa or bulimia nervosa and nonpatient volunteers (normal-weight or overweight dieters, and normal-weight nondieters). After all preloads, anorectics ate significantly less than all other subjects except normal-weight dieters, and anorectics rated hunger and desire to eat consistently lower and fullness greater than all other subjects. When analysis of intake was adjusted for body weight, anorectics and normal-weight dieters still consumed significantly less than controls. Anorectics selected foods that were lower in fat and carbohydrate and ate a larger proportion of calories as protein than the other subjects. All groups decreased subsequent intake after the high-calorie preload except bulimics. This study demonstrates that the regulatory capacity of eating-disordered individuals can be investigated and that aberrant eating behavior was observed.

Disturbed cholecystokinin secretion in patients with eating disorders

It has been shown that the gastrointestinal hormone cholecystokinin (CCK) induces satiety and reduces food intake in laboratory animals and humans. In the light of this evidence we studied CCK release in patients suffering from eating disorders. The secretion of CCK into the general circulation was measured in 10 anorectic, in 7 bulimic patients, and in 8 healthy controls before and after a high-caloric liquid testmeal. Baseline CCK values were similar in controls (0.6 +/- 0.2 pmol/l) and bulimics (0.6 +/- 0.1 pmol/l) and were significantly increased in the anorectic group (1.8 +/- 0.4 pmol/l) (p less than or equal to 0.005). After eating peak plasma levels increased to 6.1 +/- 0.9 pmol/l in the anorectic, to 3.8 +/- 0.5 pmol/l in the bulimic and to 2.7 +/- 0.6 pmol/l in the control group. All postprandial CCK values were significantly higher in the anorectic group. The secretion of CCK-8-S, an important peptide in the CCK family, was significantly elevated, too. This disturbed CCK secretion in patients suffering from anorexia nervosa, even if it is a secondary, diet-induced defect, may perpetuate this disorder.

The influence of food on food intake: methodological problems and mechanisms of action

Emphasis has been placed on the understanding of the regulation of food intake in the hope of aiding the battle against obesity and of helping to ameliorate the anorexia of cancer and eating disorders. Available data suggest that the regulatory system is multifaceted and complex. This review focuses on current research on the regulation of appetite and satiety by carbohydrates, fats, and proteins as well as by artificial sweeteners. Some methodological problems and potential mechanisms of action at the biochemical level are discussed. Evidence suggests that organisms are more successful in defending against calorie dilution than in adjusting to increases in calories. The implications of that defense relative to the use of ersatz nutrients are explored.

Biomedical variables in the eating disorders

Anorexia nervosa and bulimia nervosa are complex psychosomatic illnesses for which there may be significant biomedical diatheses and sequelae. This paper reviews these biomedical variables, focusing on the medical and nutritional assessment and management of patients with eating disorders and the medical complications that arise in these patients. The paper then examines the relationship between medical illness and eating disorders, including the medical misdiagnoses often given to these patients and the way in which a chronic medical condition such as diabetes mellitus predisposes a patient to an eating disorder. The relationship between eating disorders and pregnancy is also discussed. Through an understanding of these biomedical issues, iatrogenesis can be prevented and treatment can be improved.

Effects of cholecystokinin (CCK-8) on two classes of gastroduodenal vagal afferent fibre

In order to investigate the vagal afferent pathway responsible for the previously reported effects of cholecystokinin (CCK) on gastric emptying and food intake, single afferent fibres were recorded from the cervical vagus of urethane-anaesthetized ferrets. Sixty tension receptor afferents with receptive fields in the corpus, antrum, duodenum, jejunum and ileum all showed a resting level of discharge which was augmented powerfully by distension of the segment containing the ending. Close intraarterial injection of CCK-8 (100-200 pmol) caused relaxation in proximal regions, but enhanced contractile activity in more distal regions. Mechanoreceptor discharge closely followed intraluminal pressure at all times, indicating a sensitivity primarily to tension and no direct sensitivity to CCK. Only duodenal tension receptors were significantly excited by CCK (due to increased contractile activity), whereas those in the stomach showed a net decrease. Thirty-seven mucosal receptors from the corpus, antrum, duodenum and jejunum showed responses to luminal stimuli: predominantly light stroking, acidity and hypertonicity as has been previously described. No responses to glucose or amino-acid infusions could be evoked. However, mucosal fibres showed a strong sensitivity to close-intraarterially injected CCK-8 (3-200 pmol) in 19/26 fibres tested. These responses were unaffected by cholinergic blockade when tested. The data strongly suggest that in the ferret only vagal mucosal receptors are directly sensitive to CCK-8. These fibres are therefore likely candidates for mediating some of the reflex and behavioural effects of CCK when it is released from the gastrointestinal tract and acts directly on vagal sensory endings.

The serotonin hypothesis of bulimia nervosa: theory and evidence

Bulimia nervosa is an eating disorder with multiple causes that has been the object of extensive research since it was first described in 1979. This review evaluates both the theoretical rationale and empirical evidence for a model which suggests that disturbed serotonin activity is involved in the development of this disorder. Limitations of the hypothesis and prospects for the future are considered.

Chest pain in teenagers. When is it significant?

Chest pain in teenagers often has no obvious organic cause. Onset of symptoms with an emotionally stressful situation may indicate psychogenic chest pain. The differential diagnosis also includes cardiac, musculoskeletal, gastrointestinal, and respiratory disorders. Routine testing generally does not help to establish a diagnosis and may even do harm by reinforcing a patient's unspoken fear of serious illness. Most teenagers with chest pain have no such illness, and symptoms usually resolve without therapy. An important role for primary care physicians is to provide support during evaluation and follow-up.

Gastrointestinal hormones: from basic science to a clinical perspective

The gastrointestinal tract is the largest endocrine organ in the body. However, gastrointestinal hormones are not confined to the gut and many of them are delivered to their target tissue by neural and paracrine routes as well as the circulation. Regulatory peptide is therefore a more appropriate term than gastrointestinal hormone. The functions of these regulatory peptides include effects on intake, digestion and absorption of food, and changes in gut secretions, motility and growth. Since these peptides do not act alone but in concert it has been difficult to ascribe particular functions to individual peptides. However, the recent and on-going development of specific regulatory peptide agonists and antagonists has resulted in major advances in our understanding of the physiology of these peptides. In turn these findings are creating new therapeutic avenues providing some return from all the research on these gastrointestinal regulatory peptides. The somatostatin derivative (octreotide or sandostatin) is the most obvious example. Although only approved in Australia for treatment of carcinoids and VIPomas, the prospects include treatment of other gastroenteropancreatic tumours, acromegaly, idiopathic diarrhoea, fistula closure, dumping, and ERCP or post-operative pancreatitis. A new gastrokinetic agent, that acts via the motilin receptor, is undergoing trials for the treatment of impaired gastric emptying. The trophic effect of gastrointestinal peptides has clinical significance. For instance, gastrin antagonists inhibit cell proliferation of colon carcinoma cell lines. Furthermore the trophic effect of gastrin must be considered when potent gastric acid inhibitors, which cause a reflex increase in gastrin, are used. The outlook is for more mammalian regulatory peptides to be discovered adding further to the complexity.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential cholecystokinin gene expression in brain and gut of the fasted rat

Cholecystokinin (CCK) gene expression has been compared in the brain and duodenum of control and 5 days fasted rats. To study transcription, CCK mRNA was quantified using a solution hybridization assay. Large and small molecular weight CCK peptides were separated using a sequential extraction process and subsequently quantified by radioimmunoassay. In the duodenum, a fall in weight was paralleled by a decrease in CCK mRNA and in the large forms of CCK peptides. Small molecular species of CCK peptides did not change. There was no change in weight, CCK transcriptional or translational products in the brain as a whole. These data indicate location-specific differential regulation of the products of CCK gene expression in the fasted rat.

Eating behavior in bulimia

Despite our strong belief in the utility of laboratory studies of eating behavior, we also note several caveats on the data thereby obtained. First, it must be assumed that subjects' behavior is influenced by the laboratory environment and is not identical to eating behavior in a "normal" setting. Second, not all bulimic subjects who were screened for these studies actually participated, so that it is possible that the sample of patients from whom we obtained data differed in some ways from a general clinical population of women with bulimia. Nonetheless, we believe that our data provide compelling evidence that the disturbed eating behavior characteristic of bulimia nervosa can be profitably studied in the laboratory. Even under structured laboratory conditions, most bulimic patients rated one of their multicourse meals as typical of a binge, and, during that meal, consumed a much larger amount of food and ate more rapidly than did controls who were asked to overeat. The significant correlations between the sizes of the multicourse and single-course binge meals and between the size of laboratory binge meals and the size of the "naturally occurring" binge meals reported to the dietician suggest that a reproducible phenomenon is being examined. The results of our studies suggest that the abnormalities of eating behavior in bulimia nervosa cannot be viewed simply as a disturbance of carbohydrate consumption or even as the episodic consumption of a certain type of food. Rather, eating behavior in this syndrome appears more generally disturbed. The most striking difference between the binge and the nonbinge meals of bulimic patients and between the binge eating of patients and the overeating of normal persons is the amount of food consumed, not the macronutrient composition of the meals. In addition, for all four meal types, the patients were hungrier after the end of the meal than were the controls, even though the patients' average caloric intakes were generally larger and their average hunger ratings before the meals did not differ from those of the controls. Certainly, self-induced vomiting may contribute to this abnormality, but it was also observed after nonbinge meals when vomiting did not occur. Together, these data are consistent with the notion that the essential appetitive abnormality in bulimia nervosa lies in the control of the amount of food consumed, not in the consumption of a particular macronutrient or type of food. Patients with bulimia nervosa appear less responsive than normal to the signals that lead to the termination of a meal.(ABSTRACT TRUNCATED AT 400 WORDS)

The regulation of food intake by peptides

Historically, nutrients and related metabolic signals were considered to control the onset and offset of meals. Recent research has focused upon the roles of peptides found in the gastrointestinal tract and brain as alternate controllers of these processes. During a meal, the gut secretes a variety of peptides as part of the digestive process. Some of these substances, acting as hormonal or as local signals, may also provide information which is relayed to the central nervous system, causing eating to stop and producing the sense of satiety. When administered to animals or people before a meal, exogenous cholecystokinin (CCK), the most studied of the putative satiety peptides, reduces food intake in a dose-dependent manner. Recent findings support the concept that endogenous CCK acts during meals to limit meal size, and evidence is reviewed suggesting a possible pathophysiological role for CCK in bulimia. Adiposity is also regulated via peptide hormones, especially insulin. Insulin is secreted in direct proportion to adiposity, and blood-borne insulin gains access to brain areas important in the regulation of feeding. The administration of insulin into the brain causes reduced eating and weight loss.

Current perspectives on the eating disorders: I. History, psychological and biological aspects

An ongoing, major effort in psychiatry throughout the 1980s has been the study of anorexia and bulimia. In spite of ample effort on the part of researchers and clinicians, the etiology of these disorders remains elusive. Because of the multiple biological, sociocultural, and psychological forces involved and the early genesis of the disorder, an understanding of the eating disorders is tantamount to an appreciation of the developmental process itself. Part I of this paper presents a historical view of the eating disorders and reviews recent progress in classification criteria, epidemiology, biology, psychology, developmental, and analytic theory. Part II will focus on treatment, outcome, and research priorities.

Saturation of fat and cholecystokinin release: implications for pancreatic carcinogenesis

In a study to determine the effect of saturation of fats on their ability to stimulate cholecystokinin (CCK) release six normal volunteers ate five test meals containing different fats with intervals of 1 week. Plasma CCK levels were measured by a specific radioimmunoassay and the gallbladder volume was calculated from ultrasound measurements. The sodium salt of the monounsaturated fatty acid oleic acid (3.5 g) produced a significantly greater integrated CCK response than that of the saturated fatty acid stearic acid (mean [SEM] 103 [41] vs 8[41] pmol.l-1.min). The gallbladder contracted to 42 (3)% of its initial volume after oleate but remained at 89 (8)% of its initial volume after stearate. Integrated CCK responses to dietary triglycerides (30 g) also differed significantly according to the degree of saturation--277 (58) pmol.l-1.min after corn oil (predominantly diunsaturated), 143 (14) pmol.l-1.min after olive oil (predominantly monounsaturated), and 44 (12) pmol.l-1.min after suet (predominantly saturated). The finding that unsaturated fats are stronger stimulants of CCK release than saturated fats may explain the promotion of pancreatic carcinogenesis in rats by unsaturated but not saturated fats and may support the role of CCK in this effect.

Histidyl proline diketopiperazine (Cyclo [His-Pro]) in eating disorders

The authors explored the role of Cyclo [His-Pro] (CHP) in 50 adolescents who fulfilled DSM III diagnostic criteria for anorexia nervosa and bulimia. CHP, a relatively new neuro modulator which has a role in inducing satiety, was assayed in serum during routine blood work. CHP levels correlated significantly with weight in restrictor (AN-R) (R = -0.449, P less than 0.05) and bulimic anorexics (AN-B) (R = +0.489, P less than 0.01). There was no significant correlation in normal-weight bulimics (NWB) (R = +0.556, P less than 0.01). It did not correlate with weight in a depressed control group. Longitudinal data on six patients showed a similar relationship between weight, purging and CHP binge/purge activity and/or weight changes of around 2 kilograms correlated with average CHP changes of 42%. Clinical material suggests changes in satiety during CHP changes consistent with a satiety disturbance model of these disorders.