Aging and ovariectomy alter endothelium‐dependent and –independent vasodilation in the femoral principal nutrient artery

Abstract

Enhanced bone resorption and bone blood flow (BBF) occurs subsequent to ovariectomy (OVX) whereas BBF declines with age. The potential of the osseous resistance vasculature to alter BBF in postmenopausal and age‐related osteoporosis is unclear. PURPOSE: We studied the effects of age, gender, and estrogen status on endothelium‐dependent and ‐independent vasodilation of the femoral principal nutrient artery (PNA). METHODS: INTACT female (6‐, 14‐, and 24‐ mon), OVX female (6‐, 14‐, and 24‐ mon), and male (6‐ and 24‐ mon) Fischer‐344 rats were studied. PNAs were isolated and cannulated. Endothelium‐dependent (ACh: 10−9 – 10−4 M) and ‐independent (DEA NONOate: 10−10 – 10−4 M) vasodilation were assessed. RESULTS: Declines in endothelial function occurred in aged rats but no differences in gender were observed. Endothelium‐dependent vasodilation in young or middle‐aged rats did not change following OVX. In aged OVX rats, vasodilation was enhanced to similar values observed in young INTACT and young OVX rats. Endothelium‐independent vasodilation was not altered with age or gender except in middle aged OVX rats vs. their INTACT controls. DISCUSSION: These data demonstrate that OVX influences both endothelium‐dependent and –independent vasodilator responses of the osseous resistance vasculature. Supported by the NIH Grant #1 R01 HL077224‐01 (JMD) and the NHLBI Postdoctoral Supplement (RDP).