Vasorelaxant effects of oestradiols on guinea pigs: a role for gender differences.
Various studies have shown vasorelaxation properties for 17alpha- and 17beta-oestradiol. Here, we studied the effects of gender difference as well as oestrous cycle on oestradiol-induced vasorelaxation in mesenteric arteries from male and female guinea-pigs and in main uterine arteries from female guinea-pigs in vitro. Both 17alpha- and 17beta-oestradiol (0.5-20 micromol L-1) induced concentration-dependent relaxation of both mesenteric and uterine arteries preconstricted with either noradrenaline (NA; 10 micromol L-1) or KCl (125 mmol L-1) from both day-7 and day-15 female guinea-pigs. 17beta-oestradiol was more potent in relaxing arteries precontracted with NA than those pretreated with KCl, while 17alpha-oestradiol was more effective in relaxing those arteries precontracted with KCl. In mesenteric arteries from male animals, 17alpha-oestradiol was significantly (P < 0.001) more potent on arteries precontracted with NA than KCl, an effect opposite to that seen on arteries from female animals. However, both 17alpha- and 17beta-oestradiol were more potent in relaxing arteries from male animals compared with their female counterparts. These data indicate a possible role for gender differences in the vascular effects of oestradiols.
Department of Medicine, University of Liverpool, UCD, Daulby Street, Liverpool L69 3GA, UK. naderali@liverpool.ac.uk
E K
EK
Naderali
S L
SL
Smith
P J
PJ
Doyle
G
G
Williams
D000005:Abdomen / Q000098:blood supply; D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D012727:Sex Characteristics; D012965:Sodium Chloride / Q000494:pharmacology; D014599:Uterus / Q000098:blood supply; D014621:Vagina / Q000098:blood supply; D014664:Vasodilation / Q000187:drug effects*
D012965:Sodium Chloride; D004958:Estradiol; D011189:Potassium Chloride; D009638:Norepinephrine