title: Platelet hyperaggregability and increased alpha-adrenoceptor density in anorexia nervosa.
abstract: Plasma norepinephrine concentrations in a group of malnourished patients with anorexia nervosa were significantly (P less than 0.002) lower than those in an age- and sex-matched group of normal subjects. Platelet total alpha-adrenoceptor densities of these patients significantly (P less than 0.002) exceeded those of the controls. The increased total alpha-adrenoceptor density was due to an increase in the alpha 2-adrenoceptor receptor subtype, which mediates epinephrine-induced platelet aggregation. Accordingly, the aggregation response of the patients' platelets was significantly (P less than 0.002) enhanced after epinephrine challenge. We suggest that the starvation-induced fall in plasma norepinephrine levels is associated with the up-regulation of platelet alpha-adrenoceptors. This, in turn, accounts for exaggerated epinephrine-induced platelet aggregation in anorexic patients.
mesh_terms: D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism; D004088:Dihydroergotoxine / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D009638:Norepinephrine / Q000097:blood; D010974:Platelet Aggregation / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D015016:Yohimbine / Q000378:metabolism
chemical_list: D005230:Fatty Acids, Nonesterified; D011942:Receptors, Adrenergic, alpha; D004088:Dihydroergotoxine; D015016:Yohimbine; D009638:Norepinephrine; D004837:Epinephrine