Assuntos
Glucose/farmacologia , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Animais , Cálcio/fisiologia , AMP Cíclico/fisiologia , Endorfinas/farmacologia , Exocitose , Retroalimentação , Humanos , Secreção de Insulina , Lipídeos de Membrana/fisiologia , Fosfatidilinositóis/fisiologia , Fosfolipases/fisiologia , Prostaglandinas E/fisiologia , Proteína Quinase C/fisiologia , Ratos , Receptor de Insulina/fisiologia , Receptores Adrenérgicos alfa/fisiologia , Receptores de Superfície Celular/fisiologia , Receptores da Colecistocinina , Receptores Colinérgicos/fisiologia , Receptores Opioides/fisiologia , Taxa Secretória/efeitos dos fármacos , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
The lipolytic action of serotonin on isolated adipocytes from the adipose tissue of rats has been studied. The adipocytes were incubated in serotonin 10(-6) M. Changes both in concentration and composition of the free intra and extracellular fatty acids as well as diacylglycerides through liquid gas chromatography were evaluated at different intervals. A lower concentration of free fatty acids and diacylglycerides is produced during the first minutes of incubation as well as a subsequent increase in the concentration of both, which becomes greatest after 20-30 minutes. The composition of both lipidic fractions (FFA and DAG) into fatty acids at 5, 10, 20 and 30 minutes, is related to the composition of the triacylglycerides (TAG), since during the esterification process a decline in the DAG of linoleic and palmitoleic acid is observed, both acids arranging themselves preferably in the TAG 2 position. Whereas the inverse process occurs during lipolysis; i.e. an increase in the proportion of the acids in the 2 position. In the FFA fraction, a higher proportion of fatty acids, preferential by arranged in positions 1 + 3 of the TAG's is observed. Similarly a decrease is observed in the extracellular concentration of FFA in the presence of serotonin with respect to the controls, a fact which has been described by other authors. An analysis of the present data leads us to revise the possible role of "Cahill's cycle" (simultaneous activation of the DAG-acyl-transferase and the HSL-TAG-lipase) in the action of serotonin and other hormones.
Assuntos
Lipólise/efeitos dos fármacos , Serotonina/farmacologia , Tecido Adiposo/efeitos dos fármacos , Animais , Diglicerídeos/biossíntese , Epididimo/efeitos dos fármacos , Epinefrina/farmacologia , Ácidos Graxos não Esterificados/biossíntese , Masculino , Ratos , Ratos EndogâmicosAssuntos
Teste de Tolerância a Glucose/métodos , Modelos Biológicos , Administração Oral , Fatores Etários , Glicemia/análise , Ritmo Circadiano , Diabetes Mellitus/sangue , Carboidratos da Dieta/metabolismo , Glucose/administração & dosagem , Humanos , Hiperglicemia/sangue , Insulina/metabolismo , Secreção de Insulina , Matemática , Estado Pré-Diabético/sangue , Receptor de Insulina/metabolismo , Valores de Referência , FumarAssuntos
Ilhotas Pancreáticas/metabolismo , Somatostatina/metabolismo , Sequência de Aminoácidos , Cálcio/farmacologia , Glucagon/farmacologia , Glucose/farmacologia , Humanos , Ilhotas Pancreáticas/efeitos dos fármacos , Precursores de Proteínas/metabolismo , Radioimunoensaio , Somatostatina/análiseAssuntos
Glicemia , Modelos Biológicos , Animais , Cães , Humanos , Insulina/fisiologia , Receptor de Insulina/fisiologiaRESUMO
We have studied the effect of the i.v. administration of 1 g tolbutamide upon glycemia, insulinemia and serotoninemia in normal subjects and obese patients. We have seen an elevation of the last two variables in direct relationship with the previous blood sugar levels. The baseline serotonin level in obese people is higher than in normals, but the tolbutamide induced elevation is of a lesser magnitude. We believe this fact is due to the competitive action of insulin, as our obese patients have shown to have a "hyperinsulinism" with "disinsulinism".