title: Neurovascular and hemodynamic responses to hyperinsulinemia in healthy postmenopausal women.
abstract: 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.
authors.affiliation: Exercise Hemodynamic Laboratory, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Crivaldo Gomes
authors.initials: CG
authors.lastname: Cardoso
authors.forename: Daniela
authors.initials: D
authors.lastname: Sakai
authors.forename: Luiz Gustavo
authors.initials: LG
authors.lastname: Pinto
authors.forename: Eliana
authors.initials: E
authors.lastname: Labes
authors.forename: Josiane Lima
authors.initials: JL
authors.lastname: de Gusmão
authors.forename: Sandra Balieiro
authors.initials: SB
authors.lastname: Abrahão
authors.forename: Taís
authors.initials: T
authors.lastname: Tinucci
authors.forename: Décio
authors.initials: D
authors.lastname: Mion
authors.forename: Angela Maggio
authors.initials: AM
authors.lastname: da Fonseca
authors.forename: Cláudia Lúcia de Moraes
authors.initials: CL
authors.lastname: Forjaz
mesh_terms: 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
chemical_list: D001786:Blood Glucose; D007328:Insulin; D009638:Norepinephrine; D004837:Epinephrine