HORMONAL AND METABOLIC PROFILES IN SUBJECTS WITH OBSTRUCTIVE SLEEP-APNEA SYNDROME AND THE ACUTE EFFECTS OF NASAL CONTINUOUS POSITIVE AIRWAYPRESSURE (CPAP) TREATMENT

Nocturnal secretion of growth hormone is impaired in patients with obs tructive sleep apnea (OSA)I but the metabolic consequences have not be en reported. We measured blood levels of the hormones insulin, C-pepti de, growth hormone, cortisol and glucagon together with the intermedia ry metabolites of carbohydrate (glucose, pyruvate, lactate, alanine) a nd lipid metabolism [glycerol, nonesterified fatty acids (NEFA), 3-hyd roxybutyrate] in six obese nondiabetic men with OSA on two nights. In the first study, the untreated subjects showed frequent apneas and con sequent hypoxemia. The hormone and metabolite concentrations were comp ared with those obtained on the following night when the subjects were treated effectively with nasal continuous positive airway pressure (C PAP). There were no significant differences in the concentrations of i nsulin, C-peptide, cortisol or glucagon. We confirmed a marked reducti on in growth hormone concentrations in OSA, with a significant increas e on the CPAP night. The nocturnal profiles of glucose, pyruvate, lact ate, alanine and glycerol showed no differences between the two nights , but concentrations of NEFA and 3-hydroxybutyrate, both products of l ipolysis, were significantly greater on the treatment night. Because g rowth hormone has a lipolytic action, the results suggest that suppres sion of secretion of growth hormone in untreated OSA results in impair ed lipolysis, which is rapidly reversed by nasal CPAP.