Partial sequencing and tissue distribution of the canine isoforms of steroid 5alpha-reductase type I and type II.

BACKGROUND

The dog is regarded to be a valid model to test the effects of 5alpha-reductase inhibitors on prostatic growth. However, limited information is available on the characteristics or even existence of 5alpha-reductase isozymes in this species.

METHODS

Here, we set out to clone the cDNA of the dog isoforms of 5alpha-reductase type I and type II by a degenerate cloning strategy and to assess the tissue distribution of both transcripts and the enzymatic activity of the isozymes.

RESULTS

We identified two clones with homology to the human 5alpha-reductase isoforms type I and type II to be expressed in dog prostate. At the amino-acid level, these partial clones were found to exhibit a homology with their human counterparts of 83% and 88%, respectively. The expression levels of 5alpha-reductase mRNA were screened by RT-PCR in a number of dog tissues. No correlation was found between tissue mRNA expression and enzymatic 5alpha-reductase activities.

CONCLUSIONS

The present study describes the partial cloning of the dog 5alpha-reductase isozymes and their tissue distribution. These results provide additional data for the use of the dog as an animal model to investigate the role of 5alpha-reductase isozymes in steroid metabolism.