Neurovascular and hemodynamic responses to hyperinsulinemia in healthy postmenopausal women.
Acute hyperinsulinemia produces sympathetic activation, vasodilation, and cardiovascular changes in healthy young men. Postmenopausal period is accompanied by sympathetic, vascular and cardiovascular changes. Nevertheless, the effects of acute insulin infusion were not known in postmenopausal women. To study this aspect, 26 postmenopausal healthy women were submitted to an euglycemic hyperinsulinemic clamp performed during 120 min. Heart rate (HR: ECG), blood pressure (BP: oscillometric method), forearm blood flow (FBF: plethysmography), plasma norepinephrine (NE), plasma epinephrine (EP), and cardiovascular autonomic modulation (spectral analysis of R-R interval and BP variabilities) were measured before and during the clamp. Glycemia was kept similar to baseline during the clamp (84.6+/-1.2mg/dl versus 87.1+/-1.6 mg/dl), while plasma insulin increased significantly to a level of 89.3+/-5.6 microU/ml. Insulin infusion significantly increased plasma NE (+45+/-17 pg/ml), EP (+20+/-9 pg/ml), and low to high frequency ratio of R-R interval variability (LH/HF: 1.2+/-0.4), but did not change low frequency component of BP variability. FBF (+0.7+/-0.2 ml min(-1)100ml(-1)) was also significantly enhanced by hyperinsulinemia. HR and systolic BP increased with insulin infusion (+4+/-1 bat/min and +6+/-2 mmHg, respectively, P<0.05), while diastolic BP did not change. In conclusion, in healthy postmenopausal women, acute hyperinsulinemia produces sympathetic activation, and vasodilation, which results in HR and systolic BP enhancements, with no change in diastolic BP. This pattern of response is similar to the one usually observed in healthy young men.
Cardoso
Crivaldo Gomes
CG
Exercise Hemodynamic Laboratory, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
Sakai
Daniela
D
Pinto
Luiz Gustavo
LG
Labes
Eliana
E
de Gusmão
Josiane Lima
JL
Abrahão
Sandra Balieiro
SB
Tinucci
Taís
T
Mion
Décio
D
da Fonseca
Angela Maggio
AM
Forjaz
Cláudia Lúcia de Moraes
CL
D001783:Blood Flow Velocity / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D015309:Glucose Clamp Technique; D006439:Hemodynamics; D006801:Humans; D006946:Hyperinsulinism / Q000503:physiopathology*; D007328:Insulin / Q000378:metabolism*; D008875:Middle Aged; D009638:Norepinephrine / Q000378:metabolism; D017698:Postmenopause / Q000502:physiology*; D012016:Reference Values
D001786:Blood Glucose; D007328:Insulin; D009638:Norepinephrine; D004837:Epinephrine