title: Novel adipocyte aminopeptidases are selectively upregulated by insulin in healthy and obese rats.
abstract: The lack of a complete assembly of the sensitivity of subcellular aminopeptidase (AP) activities to insulin in different pathophysiological conditions has hampered the complete view of the adipocyte metabolic pathways and its implications in these conditions. Here we investigated the influence of insulin on basic AP (APB), neutral puromycin-sensitive AP (PSA), and neutral puromycin-insensitive AP (APM) in high and low density microsomal and plasma membrane fractions from adipocytes of healthy and obese rats. Catalytic activities of these enzymes were fluorometrically monitoring in these fractions with or without insulin stimulus. Canonical traffic such as insulin-regulated AP was not detected for these novel adipocyte APs in healthy and obese rats. However, insulin increased APM in low density microsomal and plasma membrane fractions from healthy rats, APB in high density microsomal fraction from obese rats and PSA in plasma membrane fraction from healthy rats. A new concept of intracellular compartment-dependent upregulation of AP enzyme activities by insulin emerges from these data. This relatively selective regulation has pathophysiological significance, since these enzymes are well known to act as catalysts and receptor of peptides directly related to energy metabolism. Overall, the regulation of each one of these enzyme activities reflects certain dysfunction in obese individuals.
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Rafaela Fadoni
authors.initials: RF
authors.lastname: Alponti
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Patricia Lucio
authors.initials: PL
authors.lastname: Alves
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil paulo.silveira@butantan.gov.br.
authors.forename: Paulo Flavio
authors.initials: PF
authors.lastname: Silveira
mesh_terms: D017667:Adipocytes / Q000201:enzymology* / Q000648:ultrastructure; D000626:Aminopeptidases / Q000378:metabolism*; D000818:Animals; D018826:CD13 Antigens / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008861:Microsomes / Q000201:enzymology; D009765:Obesity / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007328:Insulin; D000626:Aminopeptidases; C025579:enkephalin degrading enzyme; D018826:CD13 Antigens; C019721:aminopeptidase B
keywords: adipocyte; insulin; obesity; physiology; protein biochemistry