Estrogen Receptor (α and β) Expression in the Excurrent Ducts of the Adult Male Rat Reproductive Tract

Abstract

The understanding of estrogen's function in the male reproductive tract is limited, and estrogen receptor (ER) localization in the reproductive tract of the adult male rat has not been described. In the present study, ERα was localized by immunohistochemistry using ER21 antibody, which recognizes only ERα. Strongest immunoreactivity was seen in epithelia of ductuli efferentes and the initial segment of the epididymis. Nuclei of both ciliated and nonciliated cells were positive. The epithelium of the rete testis, and caput, corpus, and cauda epididymides stained less intensely for ERα. The vas deferens epithelium was ERα‐negative. Stromal tissue in the excurrent ducts was also ERα‐positive. Using 3H‐estradiol autoradiography, specific binding of estradiol was seen in nuclei of ductuli efferentes. Estrogen receptor α mRNA expression was greatly enhanced in ductuli efferentes compared to other regions of the male tract and was 3.5x greater than in the uterus. For comparison, the presence of ERβ was determined using reverse transcription‐polymerase chain reaction (RT‐PCR) amplification. Estrogen receptor β mRNA was expressed throughout the male tract and in the prostate. These results indicate that all organs in the male excurrent ductal system of the rat express ERα and are potential targets of estrogen. However, the ductuli efferentes are the site of the most intense ERα expression. The role of ERβ remains to be determined, but its expression appears ubiguitous in the male tract.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis–Epididymal Complex in the Normal and Cryptorchid Dog

“…As known, estrogens have an important role in maintenance of some aspects of epididymal physiology [ 14 ]. The expression of ERs has been widely documented in the epididymis of several species (mice, rats, dogs, cats, and monkeys) [ 32 , 35 , 36 , 46 , 58 ] with a common observation of the presence of ER-alpha in the efferent ductules that not only provide to the reabsorption of more than 90% of the rete testis fluid but concentrate sperm for epididymal storage [ 59 ]. In addition, the very wide GPER expression in the epididymis of pigs [ 28 , 60 ], rats [ 30 ], sheep [ 61 ] and in humans’ ductuli efferents and proximal epididymis [ 29 ] suggests its involvement in sperm maturation, protection, and storage.…”

“…On the contrary, in dogs, limited studies have shown its presence in testes with and without tumors [ 31 ], and no data are available for dog epididymis. On the other hand, the pattern of classic estrogen receptors’ protein abundance was studied in the male reproductive tracts of some animal species including dogs [ 32 , 33 , 34 ], humans [ 35 ], and rodents [ 26 , 36 ], evidencing some differences in their distribution. In our opinion, knowledge is limited regarding both the tissue-specific distribution and coexistence of these three estrogen receptors in normal and cryptorchid conditions in dogs.…”

Male animal sterilization: history, current practices, and potential methods for replacing castration

“…Similar research on females concluded that production of sterility was due to the precise targeting of the kisspeptin neurons during a critical period of neonatal development, which permanently suppressed pituitary gonadotrophins LH and FSH ( 57 ). Regardless of testicular effects, estrogen also has direct effects on the reproductive tract, particularly targeting the efferent ductules, where ESR has the highest expression and is co-expressed with AR ( 440 , 441 ). Disrupting the ESR1 or AR pathway in the male reproductive tract can permanently disrupt luminal physiology, leading to back-pressure atrophy of the testis, independent of the HPG axis ( 132 , 133 , 139 , 440 ).…”

Seasonal variations of testis anatomy and of G‐coupled oestrogen receptor 1 expression in Gerbillus gerbillus

“…Besides androgens, other steroids, notably oestrogens, play a key role in male reproductive physiology; they influence the hypothalamic-pituitary-testis axis and spermatogenesis by acting on Sertoli, Leydig and germ cell functions (Hess et al, 1997;O'Donnell et al, 2001). Oestrogens are involved in spermatogonial stem cell division (Miura et al, 1999).…”