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

The in vitro metabolism of [3H] testosterone (17beta-hydroxy-4-androsten-3-one), [3H] androstenedione (4-androstene-3,17-dione) and [3H] dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) by cauda epididymal spermatozoa from the rat, rabbit, hamster, guinea-pig and ram, varied between species. There were differences in the androgens utilized, the extent of their conversion and the identities of the metabolites formed. Of the steroid substrates tested rat spermatozoa metabolized testosterone preferentially while spermatozoa from guinea-pig transformed [3H] dehydroepiandrosterone (DHEA) almost exclusively. Rabbit spermatozoa converted all three [3H] androgens while hamster sperm utilized [3H] testosterone and [3H] DHEA. Spermatozoa collected from rams killed at the abattoir metabolized both [3H] androstenedione and [3H] DHEA but this capacity was dramatically reduced in spermatozoa collected from rams subjected to short-term anaesthesea. The results are discussed in relation to the possible direct roles of androgens in sperm physiology.
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PMID:In vitro metabolism of androgens by mammalian cauda epididymal spermatozoa. 15 59

We previously demonstrated that the caput epididymis of intact sexually mature rabbits contains a specific high-affinity binding protein for 5alpha-dihydrotestosterone (5alphaDHT). The other anatomical segments (corpus and cauda) of the epididymes of these animals had no detectable 5alphaDHT-binding activity. We have further shown that this binding was due to an androgen-binding protein of testicular origin. In the present study we have investigated 5alphaDHT binding to epididymal cytosol from sexually immature rabbits (20-104 days old). Using sucrose gradient ultracentrifugation, we have detected a unique pattern of binding. The pattern correlated well with testicular and epididymal maturation, but there was little correlation with chronological age or body weight. In the most immature animals (Group I) the seminiferous tubules appeared as solid cords and the epithelium of the ductus epididymis detectable 5alphaDHT-binding activity. In the second group (Group II), there was 5alphaDHT-binding to all three segments. The seminiferous tubules of these rabbits exhibited spermatogenic activity and lumen formation. The height of the epididymal epithelium had increased uniformly throughout the duct. The third group (Group III) had 5alphaDHT-binding only in caput cytosol. Spermatogenesis had progressed to the formation of elongated spermatids in the most immature animals of this group to the release of spermatozoa in the most mature ones. The caput epithelium of this last group of rabbits was fully differentiated. Unilateral orchidectomy of Group II rabbits resulted in a decrease in [3H]5alphaDHT-binding activity on the operated side as compared to the contralateral non-operated control side, suggesting the testicular origin of the binding protein. The failure of cyproterone or cyproterone acetate to inhibit [3H]5alphaDHT-binding to the protein, the lack of effect of N-ethylmaleimide on binding, and the rapid dissociation rate of the [3H]5alphaDHT-binding protein complex suggested that the binding moiety was testicular androgen-binding protein (ABP).
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PMID:Changes in 5alpha- dihydrotestosterone binding to epididymal cytosol during sexual maturation in rabbits: correlation with morphological changes in the testis and epididymis. 17 Nov 84

1. Procedures were developed for the extraction and assay of glycolytic enzymes from the epididymis and epididymal spermatozoa of the rat. 2. The epididymis was separated into four segments for analysis. When rendered free of spermatozoa by efferent duct ligation, regional differences in enzyme activity were apparent. Phosphofructokinase, glycerol phosphate dehydrogenase and glucose 6-phosphate dehydrogenase were more active in the proximal regions of the epididymis, whereas hexokinase, lactate dehydrogenase and phosphorylase were more active in the distal segment. These enzymes were less active in the epididymis of castrated animals and less difference was apparent between the proximal and distal segments. However, the corpus epididymidis from castrated rats had lower activities of almost all enzymes compared with other epididymal segments. 3. Spermatozoa required sonication to obtain satisfactory enzyme release. Glycolytic enzymes were more active in spermatozoa than in epididymal tissue, being more than 10 times as active in the case of hexokinase, phosphoglycerate kinase and phosphoglycerate mutase. 4. The specific activities of a number of enzymes in the epididymis were dependent on the androgen status of the animal. These included hexokinase, phosphofructokinase, aldolase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, pyruvate kinase, glycerol phosphate dehydrogenase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and phosphorylase. 5. The caput and cauda epididymidis differed in the extent to which enzyme activities changed in response to an altered androgen status. The most notable examples were hexokinase, phosphofructokinase, aldolase, phosphoglycerate kinase, 6-phosphogluconate dehydrogenase and phosphorylase.
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PMID:Activity and androgenic control of glycolytic enzymes in the epididymis and epididymal spermatozoa of the rat. 18 56

The effect of cyclic adenosine 3':5'-monophosphate (cAMP) and caffeine on the motility of spermatozoa obtained in vivo by micropuncture from the rat rete testis, caput epidiymidis, and cauda epididymidis was studied. Spermatozoa from all sites were immobile in their native fluid. Rete testis spermatozoa were not motile under any experimental conditions. After dilution in salt solution, some caput sperm exhibited circular motion, whereas most cauda sperm swam progressively. Dextrose enhanced the motility of sperm from both epidiymal sites. Caffeine further increased the motility of epididymal sperm. Dibutyryl cAMP and cAMP stimulated caput spermatozoa but had no effect on cauda spermatozoa.
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PMID:Micropuncture studies of the motility of rete testis and epididymal spermatozoa. 18 86

An in vitro test system, involving gametes of Xenopus laevis has been used to study the effect of antifertility agents upon spermatozoa as manifest in developing embryos. Exposure to either the isomeric forms of dimethylmyleran, methyl methanesulphonate or gamma-radiation led to development of a range of embryopathies, whereas treatment with steroidal drugs or the rodent epididymal chemosterilants alpha-chlorohydrin and trimethylphosphate was compatible with production of apparently normal offspring.
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PMID:Embryopathies due to spermatozoal impairment in Xenopus laevis. 20 23

The prolactin concentration in human seminal plasma and in human epididymal cauda fluid was assessed by radioimmunoassay. The prolactin concentration in cauda plasma was found to be similar to that found in male blood serum (5.5 to 9.1 ng/ml) and significantly lower than the concentration of the hormone found in seminal plasma obtained either from euspermic (48 +/- 12 ng/ml) or from vasectomized volunteers (50 +/- 10.2 ng/ml) (P less than 0.001). Calcium binding and/or transport in ejaculated spermatozoa were found to be little (0.29 +/- 0.08 nmoles/10(8) cells) and dependent on a quickly saturable process. The addition of 200 ng of human prolactin/ml induced a 60% increase in this parameter, while 50 ng of prolactin/ml were ineffective. Epididymal human spermatozoa differ from ejaculated sperm cells in showing greater, time-dependent, calcium binding and/or transport under basal conditions (2.00 +/- 0.35 nmoles/10(8) cells/hour), and in being more susceptible to the stimulating action of prolactin (4.4 +/- 0.68 nmoles/10(8) cells/hour in the presence of 50 ng of prolactin/ml).
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PMID:Effect of prolactin on the calcium binding and/or transport of ejaculated and epididymal human spermatozoa. 22 Dec 77

1. A comparison has been made of the chemical composition of epididymal plasma from the cauda epididymidis of nine mammalian species. 2. Results have shown that epididymal plasma contains low concentrations of inorganic ions and high levels of several unusual organic constituents, among which may be mentioned glycerylphosphorylcholine, hypotaurine, carnitine and several glycosidases and phosphatases. 3. The influence of this milieu on the motility and survival of spermatozoa is discussed.
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PMID:Comparative biochemistry of mammalian epididymal plasma. 31 82

Separation of labelled nuclei by sedimentation velocity at unit gravity (Staput method) was used to study the timing of histone synthesis and replacement by testis-specific basic nuclear protein (TSP) during spermatogenesis in the mouse. Animals were injected (intratesticularly) with 1.25 micronCi per testis 3H-arginine or 2.5 micronCi per testis 3H-lysine, testis nuclei were separated, and the acid extract of each nuclear fraction was analyzed by acrylamide gel electrophoresis. The distribution of labelled histones and TSP in separated nuclei was assessed 2 h after incorporation. Changes in the labelled histone and TSP content of nuclei during subsequent differentiation (1--34 days post-label) was followed in fractions of separated testis cell nuclei and in nuclei of cauda epididymal spermatozoa. Analysis of total histone and (TSP) content indicated quantitative changes during development. Nuclei from primary spermatocytes had relatively larger amounts of histones H1 and H4. Spermatid nuclei showed a relative reduction in histones H1 and H4, coincident with the appearance of TSP in these nuclei. These results suggested that synthesis and/or removal of certain histones must occur in late primary spermatocyte and early spermatid stages of spermatogenesis. Results of labelling experiments indicated several periods of histone synthesis during spermatogenesis: (1) closely associated with the last DNA synthesis(i.e., in early primary spermatocytes), (2) late in meiotic prophase (i.e., in pachytene primary spermatocytes) and (3) simultaneous with TSP synthesis (i.e., in late spermatids). Histone H1 was more heavily labelled toward the end of the primary spermatocyte period. Histone H4 was more heavily labelled in the early primary spermatocyte period, and again at the time of TSP synthesis in spermatids. Histones synthesized before the pachytene primary spermatocyte stage appeared to be replace, but histones synthesized later in spermatogenesis appeared to be at least partially retained in epididymal spermatozoa. These results suggested that repeated specific alterations in the protein complement of the nucleus are an integral part of spermatogenic differentiation in the mouse.
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PMID:Histone synthesis and replacement during spermatogenesis in the mouse. 32 95

Oral treatment of bulls with ethylene dibromide caused a temporary reduction of the DNA and protein content and head area of epididymal and ejaculated spermatozoa.
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PMID:DNA and protein changes in the spermatozoa of bulls treated orally with ethylene dibromide. 33 93

Boar ejaculated and epididymal spermatozoa were preincubated in modified KRB or the isolated oviduct and uterine horn of an oestrous sow for 4.5-5 h at 37 degrees C before introduction into medium containing ovarian oocytes previously cultured for 24 h. At examination 17-20 h after insemination 60.6% of the total oocytes had reached at least the 2nd metaphase. The proportions of oocytes penetrated (i.e. enlarged sperm head or male pronucleus and corresponding sperm tail) were 0, 10.0 and 16.7% with ejaculated spermatozoa, and 3.3, 19.6 and 26.4% with epididymal spermatozoa preincubated in modified KRB, oviduct and uterus, respectively. Although the proportion of oocytes with morphologically normal male and female pronuclei was low (10/36 = 27.8%), the results suggest that boar spermatozoa can be capacitated in the isolated genital tract of an oestrous sow and that capacitation of epididymal is better than that of ejaculated spermatozoa.
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PMID:Sperm penetration in vitro of pig follicular oocytes matured in culture. 36 49


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