Aromatase and 5-alpha reductase gene expression: modulation by pain and morphine treatment in male rats.
BACKGROUND
The steroid hormone testosterone has been found to be greatly reduced by opioids in different experimental and clinical conditions. The purpose of this study on male rats was to determine the effects of a single injection of morphine (5 mg/Kg) on persistent pain (formalin test) and the single or combined effects on p450-aromatase and 5-alpha reductase type 1 mRNA expression in the brain, liver and testis. Testosterone was determined in the plasma and in the brain, morphine was assayed in the plasma.


RESULTS
In the morphine-treated rats, there were increases of 5-alpha reductase mRNA expression in the liver and aromatase mRNA expression in the brain and gonads. Morphine was detected in the blood of all morphine-treated rats even though there were no clear analgesic affects in the formalin-treated animals three hours after treatment. Testosterone was greatly reduced in the plasma and brain in morphine-treated subjects.


CONCLUSIONS
It appears that morphine administration can induce long-lasting genomic effects in different body areas which contribute to the strong central and peripheral testosterone levels. These changes were not always accompanied by behavioral modifications.
Department of Physiology, Neuroscience and Applied Physiology Unit, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy. aloisi@unisi.it
Anna Maria
AM
Aloisi
Ilaria
I
Ceccarelli
Paolo
P
Fiorenzani
Melinda
M
Maddalena
Alessandra
A
Rossi
Valentina
V
Tomei
Giuseppina
G
Sorda
Barbara
B
Danielli
Michele
M
Rovini
Andrea
A
Cappelli
Maurizio
M
Anzini
Antonio
A
Giordano
D000818:Animals; D001141:Aromatase / Q000235:genetics* / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D042944:Cholestenone 5 alpha-Reductase / Q000235:genetics* / Q000378:metabolism; D005557:Formaldehyde; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010146:Pain / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013739:Testosterone / Q000097:blood
D012333:RNA, Messenger; D005557:Formaldehyde; D013739:Testosterone; D009020:Morphine; D001141:Aromatase; D042944:Cholestenone 5 alpha-Reductase