Alpha-glucosidase activity in the rat epididymis under different physiological conditions

The estimation of alpha-glucosidase activity in semen is widely used as a marker of epididymal function. In the present studies, glucosidase activity was evaluated in the different segments of the rat epididymis under various physiological conditions. In addition, the effect of two known male antifertility agents, gossypol and alpha-chlorohydrin, on enzyme activity was evaluated. Enzyme activity was absent from the epidiymis of rats aged 10 and 20 days but became detectable at 30 days of age when the adult pattern of distribution (highest activity in the caput epididymis) was established. Enzyme activity was reduced significantly in all segments of the epididymis at 7 days after castration and a significant decrease in activity was also observed following the administration of either gossypol or alpha-chlorohydrin. These findings are consistent with a role for alpha-glucosidase in sperm maturation in the epididymis.     

低剂量醋酸棉酚服用前后血钾测定结果分析

于 1993年底至 1996年在山东省进行低剂量醋酸棉酚临床试验 ,服药组 30例 ,对照组 15例。样本于服药前测定血钾 2次 ,服药后第 2月至第 9月每月测定血钾一次 ,停药后再持续测定 4个月。结果 :服药前 2次测定值 (mmol/L)实验组分别为 4.0 4± 0 .40 ,4.6 1± 0 .41;对照组分别为 4.0 3± 0 .32 ,4.5 0± 0 .43。服药后 2～ 9个月实验组血钾在 3 .75～ 4.5 9范围 ;对照组为 3.86～ 4.82范围 ;停药后 4个月血钾值实验组为 3 .92～ 4.2 8,对照组为4.0 4～ 4.0 8范围。经统计学处理两组在各随访月的差异均无显著性。说明男性口服低剂量醋酸棉酚 9个月不会降低血钾 ,停药后 4个月血钾值也在正常值范围内     

Potassium leakage: not the cause of gossypol induced anti-motility in spermatozoa

Gossypol induced a dose-dependent potassium leakage from boar spermatozoa suspended either in Krebs-Ringer phosphate buffer or in isotonic tris-HCl buffer. It had, however, practically no effect on the spermatozoal intracellular sodium ion content. As spermatozoal motility arrest was observed at a much lower gossypol concentration, the gossypol anti-motility effect does not seem to have stemmed from potassium leakage.     

Effect of androgens on the activity of acid hydrolases in rat epididymis

The enzymatic activity of 6 acid hydrolases was studied in rat epididymal homogenates following castration, testosterone replacement and during postnatal growth. Acid phosphatase and N-acetyl-β-D-glucosaminidase activity decreased after castration and increased with hormonal treatment as well as during growth. β-Glucuronidase and cathepsin D activity increased during the involution of the organ and decreased or did not change with hormone treatment or during sexual maturation. Arylsulphatase and deoxyribonuclease did not recover normal activity after hormonal treatment. Their activities were particularly high in epididymal and rete testis fluid of normal animals.     

Natriuretic and kaliuretic response to potassium load: modulation by sodium intake

Potassium (K) loading is followed by a rapid increase in sodium(Na) and K excretion. To evaluate the influence of Na intakeon this effect, we studied the acute natriuretic and kaliureticresponse to a single oral K load (100 mmol) in six healthy volunteersequilibrated on a 10-, 100-, and 400-mmol Na intake. Comparedto the 100-mmol Na intake, the 400-mmol Na intake greatly enhancedthe natriuretic effect of the K load; during the 10-mmol Naintake no natriuresis but even some Na retention occurred. Thekaliuretic effect was not significantly changed and occurredat similar values of plasma K. Plasma aldosterone was suppressedduring the 400-mmol Na diet and stimulated during the 10-mmolNa diet, but the relative increments after the KCI load didnot differ among the three diets. In conclusion, whereas theeffect of a K load on kaliuresis is relatively independent ofNa intake, its effect on Na excretion varies from marked natriuresisto slight Na retention. The Na retention is probably due toacute K-induced aldosterone stimulation, and the natriuresisto K-induced increase in distal Na delivery not utilized topromote K excretion. Apparently, the integration of renal Naand K handling after a K load is such that K balance is maintainedat the cost of Na balance.     

Effect of a nonsteroidal antiandrogen, flutamide on intraluminal acidification in rat testis and epididymis

Summary. Flutamide, a pure antiandrogen was administered to intact adult male rats to study the effect of altered availability of hormones on in situ pH, PCO₂ and bicarbonate concentration ([HCO⁻₃]) of seminiferous tubules, proximal caput, middle caput, middle corpus, and proximal cauda epididymidis. The weights of the epididymis and ventral prostate as well as the plasma testosterone level showed antiandrogenic effects of flutamide. Relative to controls, flutamide elevated significantly in situ pH in proximal caput, middle caput, middle corpus and proximal cauda epididymidis but not in seminiferous tubules. In situ PCO₂ values in the above segments, after flutamide, were indistinguishable from controls and from each other but all values remained significantly higher than systemic arterial blood PCO₂. Flutamide treatment did not change the [HCO⁻₃] in systemic arterial blood or seminiferous tubules but increased markedly the values in proximal caput and middle caput. The results of the present studies support the view that luminal acidification in the rat epididymis is under androgen control and may be important for sperm maturation and storage.     

Ultrastructural effects of cadmium on the rat epididymis

The short-term effect of a subcutaneous injection of 3 μmol of cadmium chloride/100 g body weight were examined 90 min later in male rats. The main target of cadmium, as shown by electron microscopy, was the endothelial lining of capillaries of the caput epididymidis. Intercellular junctions between endothelial cells were disorganized, ranging from slight separation between cytoplasmic leaflets to wide gaps which communicated freely with the pericapillary tissue. Disruption of platelets and intravascular clotting followed these early endothelial lesions, and clotting was found in venules as an extension of clotting from the capillaries. Pre-treatment with zinc (300 μmol zinc chloride/100 g body weight) prevented all of the lesions described above.     

The effect of gossypol acetic acid on the different stages of the spermatogenic cycle in the rat

The reversibility of the effect of gossypol on testicular histology and fertility was studied in rats. Adult males of proven fertility were treated orally with gossypol acetic acid (15 mg/kg) for 9 or 16 weeks (groups 1 and 2, respectively). Another groups of animals (group 3) was given gossypol (15 mg/kg) for 16 weeks and killed 6 weeks after the end of treatment. Control animals (group 4) were given the vehicle only by oral intubation. In the mating studies, although only 33% of the animals in group 1 were infertile, 100% infertility was observed following 16 weeks of gossypol treatment (group 2). All animals in group 3 regained their fertility 6 weeks after cessation of drug treatment. Damage was observed to 15.7% of the seminiferous tubules after 9 weeks of drug treatment, and to 78% after 16 weeks of treatment. Extensive vacuolization, increased numbers of lipid droplets, degeneration of germ cells, loosening of the epithelium, and a significant decrease in the number of pachytene spermatocytes (stages VII-X) and spermatids (steps 7-10 at stages VII-X) were observed after gossypol treatment. There was a decrease in the diameter of only stage VIII seminiferous tubules after 9 weeks of treatment, whereas a reduction was observed in the tubules of all stages after 16 weeks of gossypol treatment. In the recovery phase, the diameter of seminiferous tubules was similar to that of controls, except for tubules at stage VIII. No change in the area of the lumen of the seminiferous tubules and lipid bodies was observed after 9 weeks of drug treatment, but a marked reduction in the area of the lumen (stages II-X) and an increase in lipid bodies (all stages) was observed after 16 weeks of gossypol treatment. Six weeks after cessation of treatment, the area of the lumen and the number of lipid bodies were comparable to values in controls. A reduction in the area of the epithelium was restricted to just a few stages (VIII-XIV) in treated animals at 9 weeks, whereas after 16 weeks the area of the epithelium was decreased in all tubules. In the recovery phase, except for tubules at stage VIII, the area of the seminiferous epithelium was comparable to that in controls.     

Origin of the luminal fluid proteins of the rat epididymis

Using a combined microperfusion and high resolution gel electrophoresis technique, the origin of the epididymal fluid proteins of the rat has been investigated. Some proteins originate from the testis, others are secreted by the epididymis or are released by spermatozoa. Of particular interest is a 32 000 dalton protein found to be actively secreted by the caput epithelium in situ and concenrated in the lumen. The cauda epididymidis contained the highest concentration of this protein. Radioactive labelling of the sperm surface proteins revealed that this protein was present on the surface of the mature cauda but not on the immature caput or corpus sperm, suggesting its acquisition by the sperm surface during epididymal transit. Another sperm surface protein of interest (MW 40 000) is present only on the plasma membrane of the cauda but not on that of the caput or corpus sperm. Since this protein was not identified in the epididymal perfusates or luminal fluids, its presence may result from some modification events taking place in the sperm membrane during maturation.     

Secretion of macromolecules by the rat epididymis

Sperm maturation in the rat epididymis is dependent on the secretion of specific proteins by the epididymal epithelium and subsequent interaction of these proteins with spermatozoa. Evidence has shown that fertility and motility development of epididymal spermatozoa may be impaired by interfering the interaction of these proteins with spermatozoa. When the spermatozoa reach the cauda epididymidis, they are fully mature but their longevity is maintained by being stored in a quiescent state in the cauda. The unique ionic medium therein (low Na⁺, low Ca²⁺, high K⁺ and low pH) suppresses sperm motility and hence reserving energy for the vital processes of capacitation and fertilization. During ejaculation, when the spermatozoa are mixed with the copious secretion from the accessory glands they burst into vigorous motility. This results from an influx of sodium coupled to efflux of K⁺ and H⁺ across the mature sperm membrane. In the presence of a peptide secreted by the cauda epididymidis, these ionic events activate the already mature but otherwise inactive spermatozoa to full motility.     

Impact of diabetic hyperglycaemia and insulin therapy on autophagy and impairment in rat epididymis

Blood glucose dysregulation and hyperglycaemia caused by diabetes mellitus are intimately associated with male infertility. Two-month-old Sprague-Dawley rats were given a single dose of streptozotocin (55 mg/kg) by intraperitoneal injection to induce type I diabetes mellitus (DM group). The treatment group was given 1 unit/day of insulin for 16 weeks (INS group). The normal control group (NC group) was given food ad libitum. In the DM group, the histological analysis of caput and cauda epididymal ducts showed broken stereocilia and more lipid vacuolisations in the principal cells. The interstitial hyperplasia and inflammatory cell infiltration were observed in epididymal tissues. Transmission electron microscopy observation showed that the principal cells in the DM group contained more vacuoles, partly lost stereocilia, and swollen mitochondria. The autophagosomes were observed as well. Western blotting results of LC3II/I and P62 protein expression indicated that autophagy was downregulated in the DM group. The total antioxidant activity and GPx5 expression of epididymal tissues were also decreased. In the INS group, significant improvements were observed in epididymal tissues. Our study suggests that diabetic hyperglycaemia causes autophagy dysregulation in epididymal tissues, which may play a role in diabetes-induced rat epididymal injury. Insulin treatment is beneficial for diabetic-associated epididymal dysfunction.     

Ultrastructural effects of cadmium on the epididymis of the cryptorchid rat

The short-term (90 min) effect of an intraperitoneal injection of cadmium chloride (3 mumol/100 g body weight) was studied with the electron microscope in the epididymis of mature rats rendered unilaterally cryptorchid 60 days before injection. It was found that the endothelium of the epididymal capillaries of the cryptorchid organ, at this low dose and short time, showed neither separation of cytoplasmic leaflets, nor platelet damage, nor extravasation, which are the lesions previously described by us and which were present in the contralateral, scrotal epididymis. The possible mechanisms for the protective action of cryptorchidism against the effects of cadmium on capillary endothelia are discussed.     

An analysis of the direct effects of gossypol on human spermatozoa

The direct effects of gossypol and its acetic acid adduct, on the movement and functional competence of human spermatozoa were investigated employing exposure times of 1, 5 or 15 min and concentrations of 50 μM, 500 μM and 1000 μM. These compounds markedly reduced the motility, velocity, frequency of sperm head rotation and linearity of sperm progression, the most significant effects being observed with gossypol acetic acid on populations of 'capacitated' spermatozoa. Significant direct effects of gossypol on the ability of human spermatozoa to penetrate both cervical mucus and zona-free hamster ova were also observed, which were independent of any effects on motility. These results reinforce the notion that gossypol may serve a contraceptive role in the female as a 'spermicidal' agent, and suggest that this compound may also be of scientific value as a probe for identifying and isolating functionally important components of the human spermatozoon.     

Decrease in serum potassium concentration during epidural anaesthesia

A mean decrease in the arterial serum potassium concentration (S-K) of 0.40 mmol/l (range 0-1.0) was found in 45 elderly men who were studied before and after induction of epidural anaesthesia (using mepivacaine 2% with adrenaline). The decrease was similar in patients who received acetated Ringer solution or dextran 40 in normal saline as intravenous fluid supplementation. No difference in S-K change was found between patients with a normal (less than 115 mumol/l) or elevated serum creatinine concentration. The decrease in S-K prevailed at the end of surgery except in patients with an elevated serum creatinine. Corrections of S-K for changes in arterial blood pH and rectal temperature during induction of anaesthesia did not explain the decrease in S-K. Correlations of clinical parameters such as the extension of anaesthesia, amount of intravenous fluid given and blood pressure changes gave conflicting results. A smaller decrease or no change in S-K was usually seen in arterial (n = 7) and venous (n = 7) samples when no intravenous fluid was given, as well as in venous samples when acetated Ringer solution was given (n = 6).     

Effect of piperine on the epididymis of adult male rats

Aim： To study the effect of piperine on the epididymal antioxidant system of adult male rats. Methods： Adult male rats were orally administered piperine at doses of 1 mg/kg, 10 mg/kg and 100 mg/kg body weight each day for 30 consecutive days. Twenty-four hours after the last treatment, the rats were weighed and killed with ether and the epididymis was dissected from the bodies. Sperm collected from the cauda region of the epididymis was used for the assessment of its count, motility and viability. Caput, corpus and cauda regions of the epididymis were separated and homogenized separately to obtain 10 % homogenates. The supernatants were used for the assays of sialic acid, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, lipid peroxidation and hydrogen peroxide generation. Results： Body weight of the piperine-treated rats remained unchanged. The weights of the caput, corpus and cauda regions of the epididymis significantly decreased at dose of 100 mg/kg. Epididymal sperm count and motility decreased at 10 mg/kg and 100 mg/kg, and sperm viability decreased significantly at 100 mg/kg. Sialic acid levels in the epididymis decreased significantly at 100 mg/kg while significant decrease in the cauda region alone was observed at 10 mg/kg. A significant decline in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, along with an increase in hydrogen peroxide generation and lipid peroxidation were observed at 10 mg/kg and 100 mg/kg. Conclusion： Piperine caused a decrease in the activity of antioxidant enzymes and sialic acid levels in the epididymis and thereby increased reactive oxygen species levels that could damage the epididymal environment and sperm function.     

Effect of low doses of alpha chlorohydrin on the enzymes of glycolytic and phosphogluconate pathways in the rat testis and epididymis

A biochemical study has been made of the effects of low doses of alpha chlorohydrin on all the glycolytic enzymes and two key enzymes of phosphogluconate pathway i.e. glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH) of rat testis and epididymis. All the glycolytic enzymes of testis and epididymis are decreased after treatment with alpha chlorohydrin. G-6-PDH and 6-PGDH are decreased only in epididymis and not in the testis. LDH, ADH and glucose-6-phosphatase were also studied histochemically to show that the drug affects the glycolytic enzymes of epididymal epithelial cells and various testicular cell types of testis. Possible significance of these results is discussed.     

醋酸棉酚对男子垂体－性腺轴功能的影响

报道２２例长期停服棉酚男子性激素的水平及其对ＬＨＲＨ和ｈＣＧ刺激的反应。２２例中，１１例生精功能未恢复者（无精子症组）的ＦＳＨ和ＬＨ基础值及其对ＬＨＲＨ刺激反应均显著高于正常对照组（１１例），而睾酮（Ｔ）基础值和Ｔ／ＬＨ比值及Ｔ对ｈＣＧ刺激反应显著低于正常对照组。生精功能恢复组（１１例）的ＦＳＨ基础值及其对ＬＨＲＨ刺激在应均显著高于正常对照组。但是，ＬＨ和Ｔ基础值及其对ＬＨＲＨ和ｈＣＧ刺激反应，二者差异不显著。这些结果说明，不适当的棉酚治疗所引起的永久无精子症者，全睾丸细胞受到严重损害，垂体－睾丸轴系功能调节发生紊乱；而适量的棉酚所引起的暂时无精子症，生精功能恢复以后，睾丸内分泌一般均正常     

Effect of dialysate sodium concentration on interdialytic increase of potassium

To evaluate the role of plasma tonicity in the postdialysis increment of plasma potassium (p[K(+)]), the outcome of two hemodiafiltration treatments that differed only in the Na(+) level in dialysate (Na(D))-143 mmol/L (high dialysate sodium concentration [H-Na(D)]) and 138 mmol/L (low dialysate sodium concentration [L-Na(D)])-were compared in the same group of uremic patients from the end of treatment (T0) to the subsequent 30 to 120 min and up to 68 h. Kt/V and intradialytic K(+) removal were comparable. At T0, plasma [Na(+)] was 145+/-1 and 137+/-1 mmol/L after H-Na(D) and L-Na(D), respectively (P<0.001). The difference in plasma tonicity persisted from T0 to T68 h. At T120, p[K(+)] was increased from the T0 value of 3.7+/-0.2 to 4.7+/-0.2 mmol/L (P<0.05) after H-Na(D), whereas it was unchanged after L-Na(D). The change of p[K(+)] was still different after 68 h (+76+/-10% and +50+/-7% in H-Na(D) and L-Na(D), respectively; P<0.05). Of note, in the first 2 h after the end of treatment, bioimpedance analysis revealed only in H-Na(D) a significant 11+/-3% decrement of phase angle that is compatible with a decrease of intracellular fluid volume at the expense of the extracellular volume. Similarly, within the same time frame, in H-Na(D), a significant reduction of mean corpuscular volume of red cells, associated with a 2 +/-1% decrease of the intracellular [K(+)], was observed. In contrast, mean corpuscular volume of red cells did not change and erythrocyte [K(+)] increased by 6+/-1% after L-Na(D) (P<0.005 versus H-Na(D)). Thus, hypertonicity significantly contributes to the increase of p[K(+)] throughout the whole interdialytic period by determining intracellular fluid volume/extracellular volume redistribution of water and K(+).