title: Sexual dimorphism in rabbit aortic endothelial function under acute hyperglycemic conditions and gender-specific responses to acute 17beta-estradiol.
abstract: Epidemiological data suggest that hyperglycemia abrogates the gender-based cardiovascular protection possibly associated with estrogens. This study was designed to investigate 1) whether rabbit aortic rings show gender differences in the development of abnormal endothelium-dependent vasodilation (EDV) under acute hyperglycemic conditions, 2) the potential role of PKC isoforms and superoxide (O2-) in acute hyperglycemia-induced vascular dysfunction, and 3) the effect of acute estrogen administration on hyperglycemia-induced endothelial dysfunction in male and female rabbits. EDV to ACh was determined before and after 3 h of treatment with high glucose (HG) in phenylephrine-precontracted aortic rings from male and female New Zealand White rabbits. Similar experiments were conducted in the presence of inhibitors of PKC-alpha, PKC-beta, and PKC-delta or an O2- scavenger. The effect of acute estrogen administration was evaluated in the presence and absence of HG. Finally, mRNA expression of PKC isoforms was measured by real-time PCR. We found that 1) 3 h of incubation with HG impairs EDV to a greater extent in female than male aorta, 2) inhibition of PKC-beta or O2- prevents HG-induced impairment of EDV in female aorta, 3) acute 17beta-estradiol aggravates HG-induced endothelial dysfunction in female, but not male, aorta, and 4) PKC-alpha and PKC-beta expression are significantly higher in female than male aorta. This study reveals the predisposition of female rabbit aorta to vascular injury under hyperglycemic conditions, possibly via activation of PKC-beta and O2- production. Furthermore, it suggests that, under hyperglycemic conditions, acute estrogen treatment is detrimental to endothelial function in female rabbits.
authors.affiliation: Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA.
authors.forename: Aditya
authors.initials: A
authors.lastname: Goel
authors.forename: Der
authors.initials: D
authors.lastname: Thor
authors.forename: Leigh
authors.initials: L
authors.lastname: Anderson
authors.forename: Roshanak
authors.initials: R
authors.lastname: Rahimian
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000201:enzymology / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology / Q000503:physiopathology*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism*; D006943:Hyperglycemia / Q000378:metabolism / Q000503:physiopathology*; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012737:Sex Factors; D013481:Superoxides / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D007527:Isoenzymes; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D013481:Superoxides; D010656:Phenylephrine; D004958:Estradiol; D015759:Ionomycin; D011493:Protein Kinase C; D005947:Glucose; D000109:Acetylcholine