There is a pressing need for more effective appetite-stimulatory therapies for many patient groups including those with cancer. We have previously demonstrated that the gastric hormone ghrelin potently enhances appetite in healthy volunteers. Here, we performed an acute, randomized, placebo-controlled, cross-over clinical trial to determine whether ghrelin stimulates appetite in cancer patients with anorexia. Seven cancer patients who reported loss of appetite were recruited from oncology clinics at Charing Cross Hospital. The main outcome measures were energy intake from a buffet meal during ghrelin or saline infusion and meal appreciation as assessed by visual analog scale. A marked increase in energy intake (31 +/- 7%; P = 0.005) was observed with ghrelin infusion compared with saline control, and every patient ate more. The meal appreciation score was greater by 28 +/- 8% (P = 0.02) with ghrelin treatment. No side effects were observed. The stimulatory effects of ghrelin on food intake and meal appreciation seen in this preliminary study suggest that ghrelin could be an effective treatment for cancer anorexia and possibly for appetite loss in other patient groups.

OBJECTIVE:To investigate whether effects on food intake are seen in obese subjects receiving exogenous administration of ghrelin. DESIGN: Randomised, double-blind, placebo-controlled study of intravenous ghrelin at doses 1 pmol/kg/min and 5 pmol/kg/ min. SUBJECTS: In all, 12 healthy lean subjects (mean body mass index (BMI) 20.570.17 kg/m 2 ) and 12 healthy overweight and obese subjects (mean BMI 31.971.02 kg/m 2 ). MEASUREMENTS: Food intake, appetite and palatability of food, ghrelin and other obesity-related hormones, growth hormone. RESULTS: Low-dose infusion of ghrelin increased ad libitum energy intake at a buffet meal in the obese group only (mean increase 36.679.4%, Po0.01.) High-dose ghrelin infusion increased energy intake in both groups (mean increase 20.1710.6% in the lean and 70.1715.5% in the obese, Po0.01 in both cases.) Ghrelin infusion increased palatability of food in the obese group. CONCLUSION: Ghrelin increases food intake in obese as well as lean subjects. Obese people are sensitive to the appetitestimulating effects of ghrelin and inhibition of circulating ghrelin may be a useful therapeutic target in the treatment of obesity.

Peptide YY (PYY) and glucagon like peptide (GLP)-1 are cosecreted from intestinal L cells, and plasma levels of both hormones rise after a meal. Peripheral administration of PYY(3-36) and GLP-1(7-36) inhibit food intake when administered alone. However, their combined effects on appetite are unknown. We studied the effects of peripheral coadministration of PYY(3-36) with GLP-1(7-36) in rodents and man. Whereas high-dose PYY(3-36) (100 nmol/kg) and high-dose GLP-1(7-36) (100 nmol/kg) inhibited feeding individually, their combination led to significantly greater feeding inhibition. Additive inhibition of feeding was also observed in the genetic obese models, ob/ob and db/db mice. At low doses of PYY(3-36) (1 nmol/kg) and GLP-1(7-36) (10 nmol/kg), which alone had no effect on food intake, coadministration led to significant reduction in food intake. To investigate potential mechanisms, c-fos immunoreactivity was quantified in the hypothalamus and brain stem. In the hypothalamic arcuate nucleus, no changes were observed after low-dose PYY(3-36) or GLP-1(7-36) individually, but there were significantly more fos-positive neurons after coadministration. In contrast, there was no evidence of additive fos-stimulation in the brain stem. Finally, we coadministered PYY(3-36) and GLP-1(7-36) in man. Ten lean fasted volunteers received 120-min infusions of saline, GLP-1(7-36) (0.4 pmol/kg.min), PYY(3-36) (0.4 pmol/kg.min), and PYY(3-36) (0.4 pmol/kg.min) + GLP-1(7-36) (0.4 pmol/kg.min) on four separate days. Energy intake from a buffet meal after combined PYY(3-36) + GLP-1(7-36) treatment was reduced by 27% and was significantly lower than that after either treatment alone. Thus, PYY(3-36) and GLP-1(7-36), cosecreted after a meal, may inhibit food intake additively.

Context:Pituitary adenomas and pheochromocytomas/paragangliomas (pheo/PGL) can occur in the same patient or in the same family. Coexistence of the two diseases could be due to either a common pathogenic mechanism or a coincidence.Objective:The objective of the investigation was to study the possible coexistence of pituitary adenoma and pheo/PGL.Design:Thirty-nine cases of sporadic or familial pheo/PGL and pituitary adenomas were investigated. Known pheo/PGL genes (SDHA-D, SDHAF2, RET, VHL, TMEM127, MAX, FH) and pituitary adenoma genes (MEN1, AIP, CDKN1B) were sequenced using next generation or Sanger sequencing. Loss of heterozygosity study and pathological studies were performed on the available tumor samples.Setting:The study was conducted at university hospitals.Patients:Thirty-nine patients with sporadic of familial pituitary adenoma and pheo/PGL participated in the study.Outcome:Outcomes included genetic screening and clinical characteristics.Results:Eleven germline mutations (five SDHB, one SDHC, one SDHD, two VHL, and two MEN1) and four variants of unknown significance (two SDHA, one SDHB, and one SDHAF2) were identified in the studied genes in our patient cohort. Tumor tissue analysis identified LOH at the SDHB locus in three pituitary adenomas and loss of heterozygosity at the MEN1 locus in two pheochromocytomas. All the pituitary adenomas of patients affected by SDHX alterations have a unique histological feature not previously described in this context.Conclusions:Mutations in the genes known to cause pheo/PGL can rarely be associated with pituitary adenomas, whereas mutation in a gene predisposing to pituitary adenomas (MEN1) can be associated with pheo/PGL. Our findings suggest that genetic testing should be considered in all patients or families with the constellation of pheo/PGL and a pituitary adenoma.

The gastrointestinal tract and the pancreas release hormones regulating satiety and body weight. Ghrelin stimulates appetite, and glucagon-like peptide-1, oxyntomodulin, peptide YY, cholecystokinin, and pancreatic polypeptide inhibit appetite. These gut hormones act to markedly alter food intake in humans and rodents. Obesity is the current major cause of premature death in the United Kingdom, killing almost 1000 people per week. Worldwide, its prevalence is accelerating. There is currently no effective answer to the pandemic of obesity, but replacement of the low levels of peptide YY observed in the obese may represent an effective antiobesity therapy.

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Carcinoid tumors are part of a heterogeneous group of gastrointestinal and pancreatic endocrine tumors that are characterized by their capacity to produce and secrete hormones, 5-hydroxytryptamine, tachykinins and other mediators. These substances are thought to be responsible for the collection of symptoms, which include diarrhea, flushing and wheezing, that is known as carcinoid syndrome. Fibrosis that occurs either local to or distant from the primary tumor is one of the hallmarks of carcinoid tumors that originate from the midgut. The fibrotic process can occur in the mesentery as a desmoplastic response and may lead to obstruction of the small bowel, but it can also occur in the lungs, skin or retroperitoneum. Importantly, up to one-third of patients develop cardiac valvulopathy. One or more products that are secreted by the tumor and enter into the circulation are likely to have a role in this process. This Review discusses the incidence and prevalence of fibrosis in carcinoid syndrome and explores evidence to date for causative agents, in particular the roles of 5-hydroxytryptamine and elements of the downstream signaling pathway. Improved understanding of the etiology of carcinoid-tumor-related fibrosis may lead to better treatments for this condition than those we currently have.

The worsening global obesity epidemic, particularly the increase in childhood obesity, has prompted research into the mechanisms of appetite regulation. Complex pathways modulate energy balance, involving appetite centres in the hypothalamus and brain stem, and hormonal signals of energy status released by the gut and by the periphery. Better understanding of appetite regulation improves understanding of the aetiology of obesity. Manipulation of this homoeostatic system offers potentially useful treatments for obesity.