Hormonal Regulation of Fluid Reabsorption in Isolated Rat Cauda Epididymidis

Wong, Patrick; Yeung, C. H.

doi:10.1210/endo-101-5-1391

Cited by 39 publications

(21 citation statements)

References 18 publications

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“…In addition, this process regulates the concentration of constituents in the luminal fluid to which sperm are exposed. Androgens influence fluid balance in the epididymis by regulating sodium and anion transport across the epithelium (Wong & Yeung 1977, Au et al 1978, Leung et al 2002 and modulate the epididymal expression of specific aquaporins, water channels that mediate water transport in many tissues (Pastor-Soler et al 2002). In this study, we have shown an effect of 5 -reductase inhibition on the expression of several genes involved in fluid and ion transport.…”

Section: Discussionmentioning

confidence: 62%

Effects of PNU157706, a dual 5alpha-reductase inhibitor, on gene expression in the rat epididymis

Henderson¹,

Cooke²,

Robaire³

2004

Journal of Endocrinology

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The epididymis is the site of sperm maturation and storage. 5 -Reductases (types 1 and 2) are key enzymes in this tissue because they convert testosterone to dihydrotestosterone (DHT), the main androgen regulating epididymal functions. Examining the consequences of inhibiting DHT formation is likely to provide important information regarding the regulation of epididymal functions, yet few inhibitor studies have focused on this tissue. To understand better DHT-mediated regulation of epididymal gene expression, we employed a dual 5 -reductase inhibitor and cDNA microarrays to examine the effects of 5 -reductase inhibition on gene expression in the initial segment, caput, corpus, and cauda epididymidis. Inhibition of epididymal 5 -reductase activity by PNU157706 was confirmed by in vitro enzyme assays. Rats were treated with 0, 0·1, 1·0 or 10 mg/kg per day PNU157706 for 28 days. The weights of DHT-dependent tissues, including the epididymis, were decreased following treatment. The effect of treatment on gene expression was dose-dependent and highly segment-specific. The initial segment responded uniquely in that a similar number of genes increased and decreased in expression compared with the other segments where the majority of affected genes decreased in expression. Some of the more dramatically affected genes were involved in signal transduction as well as fatty acid and lipid metabolism, regulation of ion and fluid transport, luminal acidification, oxidative defense and protein processing and degradation. These are essential processes contributing to the formation of an optimal luminal microenvironment required for proper sperm maturation. These results provide a novel insight into the DHT-dependent mechanisms that control epididymal functions.

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Section: Discussionmentioning

confidence: 62%

Effects of PNU157706, a dual 5alpha-reductase inhibitor, on gene expression in the rat epididymis

Henderson¹,

Cooke²,

Robaire³

2004

Journal of Endocrinology

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“…The period post adrenalectomy (10 days) employed before the assessment of efferent duct function in this study was similar to or longer than the period post adrenalectomy in other studies on the rat in which adrenal and aldosterone dependency were demonstrated in target tissues such as the renal collecting ducts (El Mernissi & Doucet, 1983a;Horisberger & Diezi, 1983) and the ductus epididymidis (Wong & Yeung, 1977;Au et al 1978;Turner & Cesarini, 1983).…”

Section: Concentration Of Electrolytes and Osmotic Pressure Of Blood mentioning

confidence: 62%

Adrenal independence of fluid and electrolyte reabsorption in the ductuli efferentes testis of the rat

Clulow²,

La³

et al. 1997

Experimental Physiology

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SUMMARYThe ductuli efferentes testis (efferent ducts) of the rat were studied to determine whether fluid and electrolyte reabsorption by the ducts is under the control of adrenal mineralocorticoids. Testicular fluid output and the rate of fluid reabsorption by the ducts were determined in sham-operated controls and in rats which had been adrenalectomized 10 days previously, adrenalectomized 10 days previously and given aldosterone therapy (75 jug kg-' day-' s.c.) from day 3 to day 10 post adrenalectomy, and in rats given injections of the aldosterone antagonist, spironolactone, for 10 days (10 mg kg-' day-' s.c.). The values for testicular fluid output and fluid flow from the efferent ducts (means + S.E.M.) in the sham-operated rats were 36 0 + 7-8 and 1-23 + 0-12 Jul h-', respectively, resulting in an estimate of fluid reabsorption by the efferent ducts of 94.8 + 1 6 % of the testicular fluid output. None of the treatments resulted in a significant change in testicular fluid output or in fluid reabsorption from the efferent ducts. Similarly, the treatments did not significantly alter the osmolality or electrolyte concentrations in fluid samples from the rete testis or the distal end of the efferent ducts (sham-operated values for rete testis and efferent duct fluid, respectively, were: osmolality, 311.2 + 1 7 and 302-7 + 5-7 mosmol kg-'; [Na+], 151-2 + 5-6 and 150 8 + 8-1 mmol 1'; [ClF], 147-9 + 6-6 and 126-7 + 2-2 mmol 1-'; [K+], 15 2 + 0 7 and 13-5 + 2 4 mmol 1-'). It is concluded that, like the homologous proximal tubule of the metanephric kidney, fluid reabsorption from the efferent ducts is independent of adrenal mineralocorticoid control.

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“…Male rats weighing 250-350 g were castrated bilaterally through a scrotal route (Wong & Yeung, 1977). The ductuli efferentes together with the testicular vessels were ligated close to the testis and the testis was removed.…”

Section: Castrationmentioning

confidence: 99%

“…There was little accumulation of PAH in the lumen. Effect of castration Since many epididymal functions are dependent on circulating androgens (Marquis & Fritz, 1965;Martan, 1969;Majumder & Turkington, 1976;Jones & Glover, 1973;Wong & Yeung, 1977), it was of interest to see whether secretion of PAH by the epididymis was also androgen dependent. Rats were castrated for 21 days and the epididymal secretion of PAH studied.…”

Section: Concentration Profile Of Pah In Epididymismentioning

confidence: 99%

Secretion of p‐aminohippurate by the rat epididymis.

Qiu¹,

Wong²

1985

The Journal of Physiology

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SUMMARY1. Secretion of p-aminohippurate (PAH) from blood into the sperm-free lumen of the rat cauda epididymidis was studied by a stop-flow luminal perfusion technique.2. After an intravenous injection of [3H]PAH, radioactive material with chromatographic properties similar to those of free PAH appeared in perfusates. The highest concentration of PAH reached in the lumen was about 3 times that of the free PAH in blood. This was achieved after equilibration of the epididymis with perfusate for 20 min.3. Luminal accumulation of PAH by the epididymis was inhibited by intravenous injection ofprobenecid (32 mg/kg). However, deprivation of androgens by castration for 21 days had no effect on secretion.4. The rate of secretion (from blood to lumen) of PAH altered in a non-linear fashion with the concentration of free PAH in the blood and showed saturation at a free blood concentration of about 4 ,smol/l. The apparent Km and Vmax values were 2 smol PAH/l blood and 0-2 ,smol PAH/h . 20 cm tubule, respectively.5. Based on the concentration profile of PAH across epididymal cells, a model was proposed for the secretion of PAH. It is concluded that the secretary mechanism is similar to that of the renal tubule.6. The significance of these results was discussed in relation to the functions of spermatozoa in the male reproductive tract.

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Hormonal Regulation of Fluid Reabsorption in Isolated Rat Cauda Epididymidis

Cited by 39 publications

References 18 publications

Effects of PNU157706, a dual 5alpha-reductase inhibitor, on gene expression in the rat epididymis

Effects of PNU157706, a dual 5alpha-reductase inhibitor, on gene expression in the rat epididymis

Adrenal independence of fluid and electrolyte reabsorption in the ductuli efferentes testis of the rat

Secretion of p‐aminohippurate by the rat epididymis.

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