Resumen

CONTRERAS, Freddy    et al. Relación entre dopamina e insulina en sujetos sanos y diabeticos tipo 2. AVFT [online]. 2006, vol.25, n.2, pp.104-109. ISSN 0798-0264.

Dopamine exerts an important role in the regulation of central nervous system, and cardiovascular, renal and endocrine systems through the stimulation of alfa and beta adrenergic receptors and DA1 and DA2 dopaminergic receptors. Several studies have shown that dopamine agonists improve hyperglicemia and hyperlipidemia in obese and diabetic mice. Objectives: To establish the relationship between dopaminergic receptors activation and insulin secretion through the use of metoclopramide(MTC) and dopamine(DA) and to determine through hemodynamic parameters the response to the activation of cardiovascular dopaminergic receptors in healthy and type 2 diabetic subjects. Materials and methods: The study was undertaken in 15 healthy subjects and 15 type diabetic subjects, with ages between 29 and 53 years, of male and female genders. The experimental design was comparative by infusing MTC at the dose of 7,5 µg/kg/min for 30 min and at the end we added DA at the dose of 0.5-3 µg/kg/min for 30 min in MTC pre-treated subjects. The drug infusions were preceded by an initial period of placebo (saline solution) of 30 minutes. The parameters studied at 0, 30, 60 and 90 minutes were: insulin, glycaemia, glycosilated haemoglobin, HOMA-IR, EKG and the measurement of heart rate, systolic blood pressure, diastolic blood pressure and mean blood pressure. Results: Dopamine induced an increase in serum insulin, systolic blood pressure and heart rate in healthy subjects but not in type 2 diabetic subjects. MTC induced a hypotensive effect in healthy subjects. Neither MTA not DA induced significant modifications in lipid profile in the subjects. Conclusions: Dopaminergic drugs induced an increase of serum insulin probably through dopaminergic receptors but we do not rule out the presence of stimulation of beta adrenergic receptors. Cardiovascular dopamine receptors also caused modifications of hemodynamic parameters in healthy subjects but it is attenuated in type 2 diabetic subjects probably due to the presence of endothelial dysfunction and sympathetic nervous systems alterations.

Palabras clave : Type 2 diabetes mellitus; dopamine; dopaminergic receptor; hypertension; dopaminergic agonists.