UTERINE ANDROGEN RECEPTOR MESSENGER-RNA EXPRESSION IN METESTROUS AND ANESTROUS BITCHES BEING HEALTHY OR SUFFERING FROM PYOMETRA

The importance of androgens for the female reproductive system has bee n investigated for decades and a number of androgen sensitive processe s has now been identified in female reproductive organs. For carnivore species no data were available so far about uterine androgen sensitiv ity and its regulation. The present study therefore aimed to investiga te whether androgen receptors (AR) are present in the dog uterus, whet her they are regulated throughout the ovarian cycle and whether pyomet ra affects their expression rate. Uterine tissue samples were collecte d from 28 bitches of different ages and various breeds. The samples we re grouped according to the stage of estrous cycle (metestrus ME or an estrus AE) and the pathological status of the uterus (i. e. suffering from pyometra or not). Androgen receptor mRNA (AR mRNA) was quantified from 500 ng of total RNA isolated from the tissue samples using an in ternally standardized reverse transcription polymerase chain reaction (RT-PCR) described previously. The amount of total RNA extractable per g tissue was elevated during pyometra. The successful amplification o f the expected 172 bp fragment from canine uterine RNA together with t he confirmation of the identity of this fragment by sequence analysis, demonstrates that AR is expressed in this particular tissue. Comparin g the expression rates in uteri from bitches during ME or AE being hea lthy (H) or suffering from pyometra (P), the only significant (p<0.01) difference was round between H and P uteri during ME with 3.5-fold lo wer expression rates in P. Although the same seems true for AE bitches , a significant difference could not be demonstrated due to the low nu mber (n=2) of diseased animals in the AE group. There was no evident e ffect of the stage of ovarian cycle on uterine AR mRNA levels.