Alpha1-adrenoceptors in testosterone-induced prostatic hypertrophy.
Modifications of rat prostatic alpha1-adrenoceptors were investigated in testosterone-induced prostatic hypertrophy. [3H]prazosin bound to a single class of binding sites with a dissociation constant of 57.9+/-5.02 pM. The greater part of the binding capacity (24.6+/-1.02 fmol/mg protein) was made up of chloroethylclonidine-resistant binding sites that showed high-affinity for oxymetazoline and 5-methyl-urapidil, and was identified as alpha1A-adrenoceptors. The remaining chloroethylclonidine-sensitive binding sites that showed low-affinity for oxymetazoline and 5-methyl-urapidil were preferentially identified as alpha1B-adrenoceptors. mRNA for the three alpha1-adrenoceptors (alpha1a, alpha1b and alpha1d) was detected. Testosterone administration produced a 23% decrease of alpha1-adrenoceptor density, likely by an increase of prostatic glandular epithelium and a decrease in the relative proportion of smooth muscle, thus of alpha1-adrenoceptor density. The steady state level of mRNAs for alpha1-adrenoceptors was not modified by testosterone treatment. These results indicate that prostate alpha1-adrenoceptors are not affected in the prostatic hypertrophy induced by testosterone.
Auger-Pourmarin
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Institute Henri Beaufour, Z.A. de Courtaboeuf, Les Ulis, France.
Roubert
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P
Chabrier
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PE
D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D011224:Prazosin / Q000378:metabolism; D011467:Prostate / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000139:chemically induced* / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012194:RNA-Directed DNA Polymerase; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*; D014316:Tritium
D018931:Antineoplastic Agents, Hormonal; D012333:RNA, Messenger; D018340:Receptors, Adrenergic, alpha-1; D014316:Tritium; D013739:Testosterone; D012194:RNA-Directed DNA Polymerase; D011224:Prazosin