Developmental Expression of an Androgen-Regulated Epididymal Protein*

Abstract

Acidic epididymal glycoprotein (AEG), an androgen-regulated secretory protein of rat epididymis, was quantitated by RIA in epididymal extracts of rats of increasing age. Although detectable at 1 day of age, significant concentrations of AEG were not measured until 20 days; concentrations increased steadily, so that by 120 days of age, AEG represented 10% of total soluble protein. AEG mRNA was detected by Northern blot analysis of RNA from epididymides of 5-day-old animals and rapidly increased in amount between 20 and 35 days, reaching a maximum at 45 days. Using immunohistochemistry, AEG was localized in epididymal epithelial cells at 1 day of age. The number of cells staining for AEG increased markedly after 15 days. At 120 days, the immunoreactivity was predominantly localized to the lumen of the epithelial duct. To delineate factors that may influence AEG expression in the developing epididymis, we measured concentrations of androgen and androgen receptor mRNA in tissue extracts prepared from animals of various ages. Androgen receptor mRNA was detectable in epididymal extracts isolated from 1- to 90-day-old animals. Epididymal androgen concentrations were high at all ages (range, 6.0-31.2 ng/g tissue). The marked increase in AEG mRNA concentration at 20 days of age was not associated with an increase in either androgen or androgen receptor mRNA concentrations, suggesting that other factors may be necessary for AEG expression.

Pem Homeobox Gene Regulatory Sequences That Direct Androgen-dependent Developmentally Regulated Gene Expression in Different Subregions of the Epididymis

“…The principal cells become much more columnar, exhibit extensions of the Golgi apparatus, and have increased numbers of vesicles (51,52). The time frame between days 20 and 30 postpartum is also when there are increases in the levels of AR (53,54), testosterone, dihydrotestosterone (47,55), and the enzyme responsible for dihydrotestosterone production, 5-␣-reductase (56). Thus, the induction of Pem Pp transcription after day 20 could be the result of increased androgen and/or androgen responsiveness, which would also be consistent with our finding that region I is necessary for androgen-dependent transcription.…”

Cysteine‐rich secretory proteins are not exclusively expressed in the male reproductive tract

“…The mechanism of this potential activity is currently unknown, but the addition of peptides corresponding to the CAP domain signature motifs and cell transfection experiments using truncated forms of CRISP2 suggest that there is a CAP protein involved in sperm-oocyte binding via the CAP domain (Maeda et al, 1999;Ellerman et al, 2006). Northern blotting data from several species shows that Crisp1 is most abundantly expressed in the epididymis (Charest et al, 1989;Haendler et al, 1993;Kratzschmar et al, 1996).…”

Developmental expression of immobilin in the rat epididymis

“…Using biochemical approaches to identify the presence of proteins and/or specific mRNAs during development along the entire epididymis, various investigators have noted a dramatic increase between 21 and 39 days of age (Faye et al, 1980;Scheer and Robaire, 1981;Brooks, 1987;Charest et al, 1989;Garrett et al, 1990). However, in situ localization of these epididymal proteins, including immobilin, during postnatal development of the epididymis is lacking.…”