Regional differences in the testosterone to dihydrotestosterone ratio in the epididymis and vas deferens of adult mice

Abstract

The concentrations of testosterone and dihydrotestosterone (DHT) were measured in the testis and in different segments of the epididymis and vas deferens of adult mice. There were marked regional variations in the concentrations of testosterone and DHT from the testis to the caudal part of the vas deferens. In the testis, testosterone was the predominant androgen (364 +/- 90 ng/g) while DHT was weakly represented (8 +/- 2 ng/g). Qualitative and quantitative changes occurred in epididymis: DHT was the main steroid in the caput (29.3 +/- 2.7 ng/g) and corpus (33.1 +/- 4.4 ng/g) while testosterone and DHT were in similar quantities in the cauda (18.6 +/- 2.6 and 19.0 +/- 2.7 ng/g, respectively). The proximal region of the vas deferens contained higher amounts (71.4 +/- 8.0 ng/g) of androgens (testosterone + DHT) than did the caput epididymidis (39.1 +/- 3.3 ng/g). Testosterone was the predominant androgen in each part of the vas deferens and its concentrations decreased from the proximal (64.5 +/- 7.5 ng/g) to the caudal (26.9 +/- 4.3 ng/g) region. Castration and section of the efferent ducts of the testis showed that the epididymis received testosterone essentially via the blood supply and that epididymal DHT was produced locally from circulating testosterone.

Effects of testosterone on muscarinic acetylcholine receptors in the rat epididymis

“…The epididymis receives rete testis fluid that has 10-to 12-fold higher androgen concentrations than normal serum (Pujol et al, 1976). Luminal and tissular androgen concentration in the caput region is also higher than in the cauda epididymis (Turner et al, 1984;Jean-Faucher et al, 1986). In the present study, bilateral orchidectomy and testosterone replacement in castrated rats were used to determine whether the steady state of mAChR mRNA is under androgen control.…”

The Region-Specific Functions of Two Ubiquitin C-Terminal Hydrolase Isozymes along the Epididymis

“…4B). The tissue androgen level is higher in the caput epididymis than in the corpus or cauda epididymis [15,38]; thus, apoptotic cells showed in the caput epididymis rather than in the corpus and cauda epididymis following efferent duct ligation. These results may suggest that UCH-L1 and UCH-L3 have reciprocal functions in the caput epididymis fol-lowing apoptotic stress induced by androgen withdrawal, as was shown with cryptorchid stress [25].…”

Age-dependent glomerular damage in the rat. Dissociation between glomerular injury and both glomerular hypertension and hypertrophy. Male gender as a primary risk factor.

“…However, we also conducted studies on castrated males and observed that glomerular volumes increased in castrated as in intact males, but that this increase in volume was not associated with the development of injury in castrated rats. This persistent increase in Vg with age in castrated males was unexpected since the androgens promote kidney growth (31,32). However, the renotrophic action of testosterone appears to be specific for tubular elements in rats with two kidneys (33) although androgens do contribute to the glomerular hypertrophy that occurs after reduction of renal mass (34).…”

“…This sex difference is clinically relevant since the rate of progression towards end stage renal failure in autosomal dominant polycystic kidney disease is significantly slower in women vs men (25). Men are at increased risk to develop end stage renal disease secondary to diabetes and hypertensive complications (26,27) and long It has been suggested that hypertrophy of the glomerular tuft provides a separate risk factor for development of glomerular injury by increased intramural tension (29)(30)(31). In the present study we measured glomerular volumes and observed an increase in volume in intact male rats from 8-12 mo of age, which preceeded the development of the injury.…”