Endocrine Abstracts

Increased activity of sympathetic nervous system (SNS) was observed in early stage of hypertension onset. The aim of our present study was to estimate catecholamines response to stress stimulus (insulin induced hypoglycaemia) in young males with early diagnosed non-treated hypertension grade 1 (HT) and normotensive controls (NT).

Methods: Insulin tolerance test (ITT, 0.1 IU/kg body weight, Actrapid HM, i.v.) was performed in 21 HT male subjects aged 20.0±0.6 (mean±S.E.M.) years with BMI 22.0±0.5 kg/m² and in 19 NT males aged 23.1±1.0 years with BMI 22.8±0.4 kg/m². Concentrations of glucose, epinephrine, norepinephrine, plasma renin activity (PRA), growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol were determined in venous plasma.

Results: Increased baseline levels of norepinephrine (P<0.05), increased response of norepinephrine (P<0.001) and decreased response of GH (P<0.001), PRL (P<0.001), ACTH (P<0.05) and cortisol (P<0.001) to hypoglycemia were found in hypertensive patients when compared to normotensive controls. We did not observe differences in PRA baseline concentration or response to insulin induced hypoglycemia.

Conclusions: The early stage of onset of hypertension (in normal weight and young patients) is associated with sympathetic overactivity and decreased pituitary response to metabolic stress stimulus. These changes may also contribute to metabolic cardiovascular risk factors.: This study was supported by the grants VEGA 2/0154/10, 2009 and VEGA-2/0084/12, 2011.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.