Influence of gender and sex hormones on 5alpha-dihydrotestosterone elicited effect in isolated left atria of rats: Role of beta-adrenoceptors and ornithine decarboxylase activity.
Androgens elicit an acute cardiotonic effect in cardiac preparations of rats. This effect is produced via an extracellular interaction that may be coupled to pertussis-sensitive G-proteins and is associated with an increase in cAMP, polyamine synthesis and intracellular calcium. The nature of the targets and the existence of a dimorphic effect in this nongenomic effect of androgens are unknown. The purpose of this study was to characterize a possible gender and sex hormone influence on the 5alpha-dihydrotestosterone-elicited cardiotonic effect, taking into account the possible role of the beta-adrenoceptors and ornithine decarboxylase activity on this response. [Float1]Regarding this, the effect of 5alpha-dihydrotestosterone on isolated left atria from male, estrogenized female and gonadectomized male and female rats was studied. The results showed that 5alpha-dihydrotestosterone-elicited cardiotonic effect was preserved independent of gender and sex hormones, being higher in control males than in the rest of the groups. This correlated with the testosterone plasma levels, except in estrogenized females, suggesting that the androgens positively and the estrogens negatively regulated the response. In all groups, 5alpha-dihydrotestosterone produced an increase in cAMP levels, but only in control males did it produce an increase in ornithine decarboxylase activity. In the other groups, the absence of an effect on ornithine decarboxylase might limit the capability of the response to the androgen. Altogether, androgens may help to control cardiac performance by a direct interaction on the heart in both sexes. Gender and sex differences in the magnitude of inotropism being due mainly to changes in beta-adrenoceptors and cAMP production and in intracellular polyamine synthesis.
Bordallo
Javier
J
Farmacología, Departamento de Medicina, Universidad de Oviedo, Spain.
Secades
Lorena
L
Bordallo
Carmen
C
Cantabrana
Begoña
B
Sánchez
Manuel
M
D000818:Animals; D015317:Biogenic Polyamines / Q000096:biosynthesis; D002369:Castration; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D013196:Dihydrotestosterone / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism / Q000502:physiology*; D006325:Heart Atria / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood
D015317:Biogenic Polyamines; D012739:Gonadal Steroid Hormones; D011943:Receptors, Adrenergic, beta; D013196:Dihydrotestosterone; D013739:Testosterone; D000242:Cyclic AMP; D009955:Ornithine Decarboxylase