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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The factors regulating the physiology of the epididymis and the induction of functional sterility by alteration of epididymal function are discussed. The threshold requirement of androgens to maintain the structural and functional integrity of the epididymis in the rat, hamster and monkey is much higher than that needed by the accessory glands. Further, the cauda epididymidis has a higher threshold requirement of androgens than the caput epididymidis and may reflect the differences in the availability and metabolism of androgens to these two segments. An inverse relationship exists between the levels of sialic acid (sialoproteins) in the epididymal luminal plasma and that bound to the spermatozoa in the cauda epididymidis. Androgen deprivation and consequent alteration of the secretory activity of the epididymis either by castration or by treatment with antiserum to LH or by the antiandrogen, cyproterone acetate, caused concurrent decrease in the levels of sialic acid in the luminal plasma and in the spermatozoa of the different regions of the epididymis. These changing patterns of sialic acid in the spermatozoa and luminal plasma may be associated with changes in the surface charge of the spermatozoa and the stabilization of the acrosome and its membranes during sperm maturation.
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PMID:Physiology of the epididymis and induction of functional sterility in the male. 82 28

Extracts of washed spermatozoa from hamster and guinea pig cauda epididymidis and of human ejaculated sperm were all found to stimulate the motility of unwashed hamster epididymal spermatozoa in vitro, and to support development of fertilizing ability. The motility of hamster spermatozoa was only sustained in the presence of both sperm extracts and appropriate energy substrates, indicating a synergistic effect of the motility-stimulating component of the sperm extracts with energy sources. Albumin was also required for the development of fertilizing ability by hamster sperm. Comparison of different combinations of energy substrates indicated that pyruvate was the most important energy source for sperm motility and the acrosome reaction, but glucose and lactate played suporting roles. In all 3 species examined, the component of the sperm extracts that was responsible for stimulating hamster sperm motility was found to be heat-stable and to have the same elution volume on a Sephadex G-10 column, with an estimated molecular weight of about 200. These properties are identical to those of the sperm motility-stimulating factor found in blood serum and adrenal gland, suggesting that the active components may be similar or possibly the same.
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PMID:The effects of sperm extracts and energy sources on the motility and acrosome reaction of hamster spermatozoa in vitro. 83 47

Glycoprotein dynamism in the mouse epididymis was studied by means ofhistoautoradiography after injection of L-fucose-1-3H. The label was detected, at thirty minutes p.i., in the area occupied by Golgi apparatus in the epithelial cells. At 4 h p.i. the label was already present inthe lumen of ductus epididymidis. At this time interval, the luminal labelling was highest in the initial segment of the epididymis and decreased against the more distal segments considerably. At ten days p.i. very high labelling was detected in the luminal contents in the terminal segment of the ductus epididymidis and in ductus deferens, the labelling in the proximal segments of the epididymis being much lower. These observations suggested a wave of labelled glycoprotein in epididymal plasma passing through the epididymis after a fucose pulse. Higher labelling was detected in so-called "clrial was seen in epididymal and uterine spermatozoa, mostly in sperm tail region.
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PMID:An autoradiographic study of macromolecular syntheses in the epithelium of the ductus epididymidis in the mouse. II. Incorporation of L-fucose-1-3H. 83 11

Concentrated suspensions of epididymal spermatozoa obtained from two strains of mice, TO and C57BL/10, were preincubated for 20 min, 1 h or 2 h before dilution and addition of (C57BL/10 X CBA)F1 eggs. While all 3 groups of TO spermatozoa demonstrated high fertility (greater than 90% of eggs subsequently cleaved), C57BL/10 spermatozoa preincubated for 20 min and 1 h gave significantly reduced fertilization rates compared with those in the 2 h group. Furthermore, the penetration rate of the C57BL/10 spermatozoa preincubated for 20 min was significantly slower than that for similarly treated TO spermatozoa, as demonstrated by a delay in the first cleavage. A long preincubation of C57BL/10 spermatozoa in a diluted rather than a concentrated suspension did not improve fertility, suggesting that optimal capacitation may be sperm concentration-dependent in some, if not all, strains of mice.
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PMID:Differing requirements for capacitation in vitro of mouse spermatozoa from two strains. 83 93

Treating bovine epididymal spermatozoa with rutamycin or rotenone inhibited both respiration and motility supported by endogenous substrates. When oxidative phosphorylation had been blocked with various inhibitors, pyruvate was metabolized to yield ATP and restored motility. Fructose, which is metabolized via glycolysis to yield ATP, was also able to resuscitate the cells. Other substrates tested (lactate, acetate, alpha-ketoglutarate, or glyoxylate) were unable to restore motility in rutamycin-treated cells. In the presence of pyruvate, the phosphorylation uncoupler, carbonylcyanide-p-trifluoromethyoxphenylhydrazone, reduced motility and ATP to common levels in untreated cells or cells treated with rutamycin or rotenone. Pyruvate is thus metabolized to produce ATP by a pathway independent of oxidative phosphorylation associated with the electron transport chain. 5-Methoxyindole-2-carboxylic acid, an inhibitor of lipoyldehydrogenase, prevented the increase of motility and ATP in rutamycin-treated cells, indicating that alpha-keto acid oxidation is involved in the production of ATP from pyruvate when rutamycin is present. With pyruvate present, bongkrekic acid, antimycin A, and anaerobiosis eliminated motility, reduced ATP to low levels, and also significantly reduced the rate of pyruvate metabolism. Acetate was produced from pyruvate only when cellular ATP concentrations were low. Decreases in free carnitine concentrations showed that pyruvate initially used was converted to acetylcarnitine. The results indicate that the intramitochondrial lactate dehydrogenase X, which is unique to spermatozoa, allows the NADH resulting from pyruvate oxidation to reduce other pyruvate molecules to lactate. Pyruvate thus competes with, and can substitute for, the NADH dehydrogenase of the electron transport chain. Pyruvate rapidly repletes the acetylcarnitine pool under a variety of conditions.
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PMID:Pyruvate metabolism in bovine epididymal spermatozoa. 83 18

A technique which permits collection of the total output of spermatozoa and fluid from the cauda epididymidis of conscious rams is described. The volume of epididymal semen collected varied in an approximately inverse proportions with the frequency of collection, but there was little variation in the concentration of spermatozoa. Chemical analyses showed that cell-free cauda epididymidis fluid contained lactic acid at various concentrations, only traces of glucose but relatively high amounts of phospholipid, pregenenolone, androgen-binding protein and 5alpha-dihydrotestosterone (5alpha-DHT). Testicular spermatozoa maintained their metabolic activity and cellular integrity when stored in cauda epididymidis fluid in vitro at low temperature. After exposure to cauda epididymidis fluid for 14 days, testicular spermatozoa were predominantly glycolytic in their mode of glucose dissimilation and in this respect they resembled ejaculated spermatozoa.
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PMID:Characteristics of semen collected from the cauda epididymis of conscious rams. 85 Feb 15

Weight, histological and biochemical changes in the rat epididymis were investigated during prepubertal, pubertal and postpubertal periods. The phase of most rapid growth of the epididymis commenced at 21 days and extended to 60 days of age; this period corresponded closely to the onset of androgen production at 3 weeks and stabilization of the leydig cell number at 60 days. Histological differentiation in the caput epididymis started before sperm entry and was complete in the cauda only several days after the spermatozoa had appeared. The presence of appreciable quantities of glycerophosphorylcholine (GPC) and sialic acid in the epididymis of 21-day-old rats suggested inherent secretory ability of the epididymal epithelium. The concentrations of GPC, sialic acid, phospholipids and glycogen in the epididymis gradually increased with age, but each came under the influence of androgen at a different age. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Maximal secretory activity of the epididymis became established only by 90 days of age.
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PMID:Functional maturation of the epididymis in the rat. 85 Feb 19

The effects of cyproterone acetate, administered via sc capsules, on the surgically separated rat epididymis and on fertility were studied. Treatment with the antiandrogen reduced the weight of the surgically separated epididymis. However, short- or long-term administration of small quantities of cyproterone acetate had no effect on the fertility of epididymal spermatozoa. The results appear to show that epididymal spermatozoa are capable of fertilization even at low levels of androgens resulting from treatment with cyproterone acetate.
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PMID:Cyproterone acetate: II. failure to reduce sperm fertility in the surgically separated epididymis of rat. 88 Aug 18

MODIFICATIONS IN RABBIT SPERM PLASMA MEMBRANES DURING EPIDIDYMAL PASSAGE AND AFTER EJACULATION WERE INVESTIGATED BY USED OF THREE LECTINS: concanavalin A (Con A); Ricinus communis I (RCA(I)); and wheat germ agglutinin (WGA). During sperm passage from caput to cauda epididymis, agglutination by WGA drastically decreased, and agglutination by RCA(I) slightly decreased, although agglutination by Con A remained approximately unchanged. After ejaculation, spermatozoa were agglutinated to a similar degree or slightly less by Con A, WGA, and RCA(I), compared to cauda epididymal spermatozoa. Ultrastructural examination of sperm lectin-binding sites with ferritin- lectin conjugates revealed differences in the densities of lectin receptors in various sperm regions, and changes in the same regions during epididymal passage and after ejaculation. Ferritin-RCA(I) showed abrupt changes in lectin site densities between acrosomal and postacrosomal regions of sperm heads. The relative amounts of ferritin-RCA(I) bound to heads of caput epididymal or ejaculated spermatozoa. Tail regions were labeled by ferritin RCA(I) almost equally on caput and cauda epididymal spermatozoa, but the middle-piece region of ejaculated spermatozoa was slightly more densely labeled than the principal-piece region, and these two regions on ejaculated spermatozoa were labeled less than on caput and cuada epididymal spermatozoa. Ferritin-WGA densely labeled the acrosomal region of caput epididymal spermatozoa, although labeling of cauda epidiymal spermatozoa was relatively sparse except in the apical area of the acrosomal region. Ejaculated spermatozoa bound only a few molecules of ferritin-WGA, even at the highest conjugate concentrations used. Caput epididymal, but not cauda epididymal or ejaculated spermatozoa, bound ferritin-WGA in the tail regions. Dramatic differences in labeling densities during epididymal passage and after ejaculation were not found with ferritin-Con A.
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PMID:Lectin-binding sites on the plasma membranes of rabbit spermatozoa. Changes in surface receptors during epididymal Maturation and after ejaculation. 90 74

A study has been made of epididymal resorption of spermatozoa in the field rat (Millardia meltada). At the height of its reproductive activity, many spermatozoa penetrate the epididymal epithelium and intertubular tissue where they undergo fragmentation and resorption. Sperm disposal is maximum in the cauda epididymidis.
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PMID:Epididymal resorption of spermatozoa in the field rat (Millardia meltada). 90 12


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