Quantification of epididymal retinoic acid-binding protein (ERABP) mRNA in different anatomical regions of the adult rat epididymis.

Epididymal retinoic acid-binding protein (ERABP), an 18.5 Kd androgen-dependent protein, is synthesized and secreted by the rat epididymis. The concentration of ERABP mRNA in different anatomical regions of the rat epididymis was measured using quantitative reverse transcription polymerase chain reaction (RT-PCR) and Northern blot analysis. While quantitative differences in the level of ERABP were observed in the caput region of the epididymis, no detectable levels of ERABP mRNA was observed in the corpus and cauda regions of the epididymis. In the caput region of the epididymis, 0.22 ng and 0.036 ng mRNA/gg of total RNA were measured in the proximal and distal segments of the caput region, respectively. These results indicate that ERABP is differentially expressed in the rat epididymis and suggest that the protein may be regulated at the level of transcription.