Fluid reabsorption in the isolated duct of the rat cauda epididymidis

Wong, Patrick; Yeung, C. H.

doi:10.1530/jrf.0.0490077

Cited by 25 publications

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“…Sodium-potassium activated ATPase appears to be involved in the sodium-dependent reabsorption of water in the isolated rat cauda epididymidis [13]; the activity of this enzyme may be androgen dependent [ 141. The elevated chloride concentrations in the caput and distal cauda after eight weeks of CA treatment would be consistent with the presence of an androgen-dependent sodium pump in the epididymal epithelium.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Cyproterone Acetate on the Elements in the Intraluminal Fluids of the Testis and Epididymis of the Rat

Jenkins

Lechène

Howards

1983

Archives of Andrology

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Section: Discussionmentioning

confidence: 99%

The Effects of Cyproterone Acetate on the Elements in the Intraluminal Fluids of the Testis and Epididymis of the Rat

Jenkins

Lechène

Howards

1983

Archives of Andrology

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“…), which would be expected if water moves passively across the epididymis secondary to a net transepithelial transport of sodium ions (Wong & Yeung, 1977, 1978. Concentration of Na+ in perfusate (mmol/1) Fig.…”

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Effect of Adrenalectomy and Hormone Replacement on Sodium and Water Transport in the Perfused Rat Cauda Epididymidis

Au¹,

Ngai²,

Yeung³

et al. 1978

Journal of Endocrinology

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In the cauda epididymidis, sodium chloride is reabsorbed isotonically with water and potassium is secreted into the ductal lumen (Wong & Yeung, 1977, 1978; these transport processes seem to have many characteristics typical of the processes occurring in the distal tubule of the kidney. Apart from electrolyte and water transport, proteins are also secreted into the ductal lumen. The epididymal epithelium actively maintains a definite milieu within the tubule in which the spermatozoa are maturing. In several transporting epithelia such as those of the toad bladder, frog skin, salivary and sweat glands, intestine and renal tubule (for references, see Hierholzer, Wiederholt & Stolte, 1966), active sodium transport is regulated by the adrenocortical hormones. This study was designed to investigate the role of the adrenal glands in regulating salt and water transport in the epididymis. Net sodium and water fluxes across the perfused rat cauda epididymidis were measured in normal and adrenalectomized rats and adrenalectomized rats injected with adrenocortical hormones.Thirty fertile Sprague-Dawley rats (350-450 g) were bilaterally adrenalectomized under sodium pentobarbitone (50 mg/kg body weight) anaesthesia and then given 1% NaCl solution instead of drinking water. After 3 days, eight rats were injected with D-aldosterone (i.p., 75 µg kg-1 day-1), eighkrats received cortisol (Efcortelan, i.p., 16 mg kg-1 day-1) and a further six rats received D-aldosterone+cortisol for 4 days before the experiment. The remaining eight animals received no further treatment.Sodium and water transport across the perfused rat cauda epididymidis were measured by the method described previously (Wong & Yeung, 1978). The cauda epididymidis (about 18 cm long) was perfused with Krebs bicarbonate solution (containing 118 mM-NaCl, 4-7 mM-KCl, 2-56 mM-CaCl2, 1-13 mM-MgS04, 1-17 mM-NaH2P04 and 25 mM-NaHC03, pH 7-4) and subsequently with solutions containing various concentrations of sodium (NaCl was replaced by choline chloride). Sodium reabsorption altered in a curvilinear manner with the concentration of sodium in the luminal fluid, with an apparent Km of about 20 mM-Na+ (Fig. la). In rats adrenalectomized for 7 days, sodium reabsorption was undetectable between 0 and 70 mM-Na+ and the rate measured at 143 mM-Na+ was de¬ pressed by about 50% compared with untreated controls (jP<0-001, Student's i-test). Injection of D-aldosterone for 4 days partially (about 40%) restored the rate of sodium reabsorption; values were significantly higher than those measured in adrenalectomized rats with the concentration of sodium between 25 and 70 mmol/1 (P<0-01). However, injection of cortisol had little if any effect on Na+ reabsorption; when D-aldosterone and cortisol were given together values were not significantly different from those observed after administration of D-aldosterone alone.

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“…The mechanism of fluid reabsorption has been studied in isolated duct of rat epididymis in vitro. It was found that 50 % of the fluid reabsorption is secondary to an active transepithelial transport of sodium ions (4,5). Furthermore this process, like many epididymal functions, is abolished by castration, indicating that the fluid reabsorption process is dependent upon the presence of circulating androgens (6).…”

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Effects of Catecholamines and Adrenergic Blockade on Fluid Reabsorption in Isolated Rat Cauda Epididymidis

Wong

Yeung

1978

Japanese Journal of Pharmacology

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Abstract-The rate of fluid reabsorption in the cauda epididymidis of rat has been measured in vitro.Both adrenaline and isoprenaline produced a prompt, reversible and dose dependent increase in the reabsorption rate. These effects were completely blocked by propranolol.The response to noradrenaline consisted of two components. I n the presence of an alpha blocker, noradrenaline caused an increase, while in the presence of a beta blocker, it produced an inhibition in the rate of fluid reabsorption. The effects of these adrenergic agents were only observed when sodium ions were present in the intraluminal fluid, suggesting that they only affect the Na+-dependent component of fluid reabsorption.The possibility that they may affect the active transport of sodium in the duct was discussed.The effects of these adrenergic agents were inter preted in terms of the presence of alpha and beta receptors in the epithelium of the rat cauda epididymidis.It is now well established that fluid reabsorption takes place along the entire length of the mammalian epididymal duct. A major part of the rete testis fluid is reabsorbed as it flows down the epididymis (1, 2, 3). The mechanism of fluid reabsorption has been studied in isolated duct of rat epididymis in vitro. It was found that 50 % of the fluid reabsorption is secondary to an active transepithelial transport of sodium ions (4, 5). Furthermore this process, like many epididymal functions, is abolished by castration, indicating that the fluid reabsorption process is dependent upon the presence of circulating androgens (6).There is little information on the role of neurotransmitters in the functions of the epididymis, although it has been shown that the cauda epididymidis is heavily innervated by sympathetic and parasympathetic nerves (7,8). In this paper, we report the effects of adrenergic agents and blockers on fluid reabsorption in isolated rat cauda epididymidis.The results were interpreted in terms of the presence of the alpha and beta adrenergic re ceptors in the epididymal epithelium. MATERIALS AND METHODSMale Sprague-Dawley rats weighing between 200-300 g were sacrificed by a blow on the head. The epididymis was quickly removed and placed in cold Kreb's bicarbonate solution.A segment of the cauda epididymidis (about 0.3 cm long) was dissected free of fat and connective tissue and placed on a specially designed platform similar to that used for measuring secretory rate in isolated rat seminiferous tubules (9). Each end was clamped onto the platform, and incisions were made in the duct close to the clamps. The lumen was

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Fluid reabsorption in the isolated duct of the rat cauda epididymidis

Cited by 25 publications

References 11 publications

The Effects of Cyproterone Acetate on the Elements in the Intraluminal Fluids of the Testis and Epididymis of the Rat

The Effects of Cyproterone Acetate on the Elements in the Intraluminal Fluids of the Testis and Epididymis of the Rat

Effect of Adrenalectomy and Hormone Replacement on Sodium and Water Transport in the Perfused Rat Cauda Epididymidis

Effects of Catecholamines and Adrenergic Blockade on Fluid Reabsorption in Isolated Rat Cauda Epididymidis

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