Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 371

CCK is present in the hypothalamus, cortex, and midbrain and is released from the lumen of the intestine in response to nutrients, particularly fat and protein, in the gut. CCK causes contraction of the gallbladder and relaxation of the sphincter of Oddi. Exogenous CCK administration decreases food intake in animals and humans. CCK is a physiological satiety hormone as its suppressive effect on food intake occurs with the administration of doses producing plasma CCK concentrations within the physiological range, and administration of CCK antagonists increases food intake in animals and young adult humans.⁴⁴ CCK also slows gastric emptying. The satiating effects of CCK appear to increase with age. Most studies in humans have shown plasma CCK concentrations to be higher in healthy older than young adults.^30,45 Elderly people with idiopathic anorexia have significantly higher plasma levels and non‐significantly higher CSF levels of CCK than healthy age‐matched controls.³⁶ Intraperitoneal CCK suppresses food intake more in old than young rats and mice. Intravenous CCK‐8 administration has been found to acutely suppress food intake twice as much (31 vs. 15%, p = 0.02) in older than young adult healthy human subjects. The combination of increased circulating CCK concentrations and enhanced sensitivity to CCK suggests that CCK may cause the anorexia of ageing and raises the possibility of using CCK antagonists to increase energy intake in undernourished older people.⁴⁶