{'fraction_non_alphanumeric': 0.028070175438596492, 'fraction_numerical': 0.0061403508771929825, 'mean_word_length': 5.338888888888889, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A beta-2-adrenergic receptor activates adenylate cyclase in human erythrocyte membranes at physiological calcium plasma concentrations.

More information is needed about the subtype of the beta-adrenergic receptor coupled to the G-protein-adenylate cyclase (AC) system in human erythrocytes and about the optimal experimental conditions to study this system. In this study we describe the characteristics of spontaneous and beta-agonist-activated AC in human erythrocytes. Human erythrocyte membranes were isolated and AC activity was utilized to assess the quantity of cAMP. Our data show that the subtype beta-2 is the functional beta-adrenergic receptor involved in such activation; this modifies the beta-adrenergic-stimulated activity of AC in human erythrocytes. Isoproterenol in a medium with calcium (1-10 mM, range that includes physiological plasma concentrations) enhances the activation of AC; this effect was blocked by propranolol, but not by atenolol. We conclude that in human erythrocytes subtype beta-2 is the functional beta-adrenergic receptor and that such a response depends to a large extent on Ca(2+) concentrations.