Impact of gender on basal and insulin-like growth factor I-regulated nitric oxide synthase activity in adult rat left ventricular myocytes.
Cardiovascular morbidity and mortality are far less in pre-menopausal women compared to age-matched men. Ovarian hormones are believed to be mainly responsible for this "female advantage" in cardiovascular function although the underlying mechanism has not been fully elucidated. A gender difference exists in vascular nitric oxide (NO) synthesis, which may play a key role in ventricular function and cardiac remodeling. This study was designed to compare NO production, basal NO synthase (NOS) expression and activity, as well as insulin-like growth factor I (IGF-1)-induced response on NOS activity in left ventricular myocytes from age-matched adult male and female Sprague-Dawley rats. NO production and protein expression of NOS, IGF-1 receptor (IGF-1R) and IGF binding protein-3 (IGFBP-3) were measured by Griess assay and Western blot analysis, respectively. NOS activity was evaluated by conversion of (3)H-arginine to (3)H-citrulline. Basal NO production, endothelial NOS expression and NOS activity were both significantly higher in female left ventricular myocytes than their male counterparts. However, protein expression of inducible and neuronal NOS as well as IGFBP-3 was comparable between the two genders. IGF-1R expression was less in female than male group. IGF-1 (10(-10)-10(-6) m) induced a concentration-dependent inhibition of NOS activity in male myocytes with a maximal inhibition of 22.2%. However, the IGF-1-induced inhibition in NOS activity was not present in left ventricular myocytes from female rats. These data revealed a gender difference in myocardial basal NO levels, endothelial NOS expression, basal NOS activity and IGF-1-induced inhibition on NOS activity, which may contribute to the gender-related difference of cardiac function.
Division of Pharmaceutical Sciences and Graduate Neuroscience Program, University of Wyoming College of Health Sciences, P.O. Box 3375, Laramie, WY 82071-3375, USA.
Lucy B
LB
Esberg
Xiaochun
X
Zhang
Glenda I
GI
Scott
Bruce
B
Culver
Jun
J
Ren
D000818:Animals; D001835:Body Weight; D002469:Cell Separation; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D006352:Heart Ventricles / Q000166:cytology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000096:biosynthesis / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D032383:Myocytes, Cardiac / Q000201:enzymology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009929:Organ Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis / Q000378:metabolism; D012727:Sex Characteristics
D018972:Insulin-Like Growth Factor Binding Protein 3; D009419:Nerve Tissue Proteins; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D017526:Receptor, IGF Type 1