Ablation of TrkB signalling in CCK neurons results in hypercortisolism and obesity

Dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity leads to debilitating neuroendocrine or metabolic disorders such as Cushing's syndrome (CS). Glucocorticoids control HPA axis activity through negative feedback to the pituitary gland and the central nervous system (CNS). However, the cellular mechanisms involved are poorly understood, particularly in the CNS. Here we show that, in mice, selective loss of TrkB signalling in cholecystokinin (CCK)-GABAergic neurons induces glucocorticoid resistance, resulting in increased corticotrophin-releasing hormone expression, chronic hypercortisolism, adrenocortical hyperplasia, glucose intolerance and mature-onset obesity, reminiscent of the human CS phenotype. Interestingly, obesity is not due to hyperphagia or decreased energy expenditure, but is associated with increased de novo lipogenesis in the liver. Our study therefore identifies CCK neurons as a novel and critical cellular component of the HPA axis, and demonstrates the requirement of TrkB for the transmission of glucocorticoid signalling

Laboratory Analysis of Vitamin C in Vegetables Served in Eldercare Facilities and Evaluation of Related Public Nutrient Database Information

Vitamin C is an important nutrient, and its labile nature means that prepared vegetables containing sufficient amounts of vitamin C are likely to be rich in other important nutrients as well. Samples of prepared green beans and carrots were obtained from eldercare facilities and their vitamin C content was determined. The results indicated a lack of consistency in the Vitamin C content, and the value for many samples was less than expected. Vitamin C content was maximized through the use of steaming followed by hot-holding for less than 20 minutes. Suggestions for improving relevant public database information are provided