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

In epididymal adipose tissue from rats, human serum antagonizes inhibition of basal lipolysis by nicotinic acid in vitro. Under similar conditions caffeine-stimulated lipolysis was unaffected by the presence of human serum. Very low density (VLDL), low density (LDL) and high density (HDL) lipoproteins were all found to antagonize the action of nicotinic acid on basal lipolysis. VLDL also antagonized prostaglandin E1 (PGE1)-inhibition of basal lipolysis in vitro. The fat cell membrane was suggested as the site at which human serum lipoproteins antagonize nicotinic acid or PGE1 antilipolytic action on basal lipolysis in vitro.
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PMID:Modification of nicotinic acid and prostaglandin E1 antilipolytic action in vitro. 18 78

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

The fertilizing ability of testicular, epididymal, and ejaculated rabbit spermatozoa was evaluated in vitro following in vitro capacitation by high ionic strength treatment. Fewer than 11% of inseminated ova were apparently fertilized (i.e., in pronuclear, two-, and four-cell stages as determined by light microscopy) when testicular sperm treated with caffeine, caput epididymal, or corpus epididymal sperm samples were tested. A greater fertilizing ability, reflected by the percentage of ova fertilized and more normal progression of embryonic development, was exhibited by cauda epididymal sperm. Of 93 ova, 68 (73.1%) were fertilized by cauda sperm, whereas ejaculated sperm from the same 10 bucks fertilized 34 (36.6%) of 93 ova (P is less than 0.005). Ultrastructural examination of selected ova apparently fertilized by sperm from levels of the male reproductive tract proximal to the cauda epididymidis revealed abnormal activation. Authentic fertilization occurred when ova were inseminated with cauda epididymal and ejaculated sperm. An unusual and infrequent form of activation involving failure of cortical granule breakdown in ova penetrated by cauda epididymal and ejaculated sperm was seen. A comparison of fertilizing ability of sperm from first, second, and third ejaculates revealed a significant decrease with the third ejaculate (P is less than 0.01).
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PMID:In vitro fertilizing ability of testicular, epididymal, and ejaculated rabbit spermatozoa. 66 37

Endothelin-1 (ET) enhances nerve-stimulated contractions in epididymal (E) and prostatic (P) halves of the rat vas deferens, in addition to raising the basal tone in E. Whereas the peak increase in basal tone occurs in about 30 s, the maximal enhancement of neurotransmission is observed within 5 min. The latter effect is long lasting and is maintained even after extensive tissue washout. Furthermore, ET potentiates, in a concentration-dependent fashion, the adenosine 5'-triphosphate (ATP) or the adenylylimidodiphosphate (AMP-PNP) but not the noradrenaline (NA)-induced motor activity. The ATP motor response is partially blocked in media without Ca2+ plus 0.1 mM EGTA or following tissue incubation in buffer containing 10-50 nM nifedipine. However, these procedures do not modify significantly the ET-induced potentiation of the ATP contractions. The ET-induced potentiation of the ATP motor response is not modified by tissue preincubation in Ca(2+)-free buffer plus 10-30 microM ryanodine or 5-20 mM caffeine. The ET-induced rise in E basal tension is significantly reduced in the absence of external Ca2+ or by nifedipine; ryanodine does not modify this effect. Surgical denervation of the tissues does not obliterate the ET-induced potentiation of the ATP motor responses nor the ET increase in E basal tension in tissues superfused in Ca(2+)-free media or buffer with 2.5 mM Ca2+. Endothelin-1 does not significantly modify the overflow of 3H-NA, following transmural electrical depolarization of tissue nerve terminals. Hoe 140 did not interfere with the ET activity.
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PMID:Endothelin-1 (ET)-induced mobilization of intracellular Ca2+ stores from the smooth muscle facilitates sympathetic cotransmission by potentiation of adenosine 5'-triphosphate (ATP) motor activity: studies in the rat vas deferens. 133 1

1. Guanethidine at 5 x 10(-6) M strongly inhibited rat prostatic but not epididymal vas deferens, reflecting differences in innervation and the neurogenic field stimulation responses of these tissues. 2. Adenosine and ATP inhibited the field stimulation responses of rat prostatic vas deferens by 56 and 50% respectively. A 10-min pretreatment with 10(-4) M caffeine partly reversed this inhibition, by 55% in the case of adenosine and 60% for ATP. 3. Pretreatment for 10 min with 5 microM quinidine failed to significantly alter the extent of either adenosine or ATP inhibition of the field stimulation responses of rat prostatic vas deferens. 4. 8-Phenyltheophylline, the selective blocker of the A1 subtype of the P1 receptor, partly reversed adenosine-induced inhibition of the vas deferens FS responses. NECA, the selective agonist of the A2 subtype of the P1 receptor, very strongly inhibited vas deferens FS responses. 5. Field stimulation responses of human vas deferens were also inhibited by both adenosine and ATP but to a lesser extent and more variably than in rat tissue. 6. Adenosine and ATP inhibition was reversed by caffeine pretreatment, but far more variably than in rat tissue, and quinidine was without significant effect on inhibition of the responses. 7. It is concluded that in these tissues adenosine and ATP may operate via a P1 type receptor of both A1 and A2 subtypes and that a P2 type receptor may be lacking.
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PMID:Purinergic modulation of field stimulation responses of rat and human vas deferens smooth muscle. 176 Nov 93

The redox behaviour of the NAD(P) system and flavoproteins was registered by simultaneous fluorescence measurements in epididymal bull spermatozoa. The flavoprotein fluorescence signal can nearly exclusively be attributed to an NAD-linked enzyme, alpha-lipoamide dehydrogenase (Em7.4 = -286 mV). A comparison of intact with digitonin-permeabilized spermatozoa revealed that about 50% of the total NAD(P)H fluorescence signal was of mitochondrial origin. Under equilibrium conditions, the midpoint potentials of the NAD(P)H fluorescence signal of both compartments were almost identical (-300 mV). When lactate was present as substrate, 1 mM caffeine increased respiration oxidizing the NAD(P)H system in both mitochondria and cytosol. This indicates a close relationship of the two NAD pools in spermatozoa.
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PMID:Use of NAD(P)H and flavoprotein fluorescence signals to characterize the redox state of pyridine nucleotides in epididymal bull spermatozoa. 200 81

Turnover rates of oxidative energy metabolism were measured as oxygen consumption in untreated and caffeine-stimulated epididymal bull spermatozoa respiring with lactate. Incubation of spermatozoa with 1 mM caffeine led to an increase in respiration of approx. 60%. The rate of uncoupled respiration and the vanadate-insensitive part of oxygen consumption were not affected by caffeine. The small effect of ouabain on respiration (-10%) indicated a minor contribution of Na+/K+-ATPase to the ATP consumption. The major part of ATP turnover was caused by motility shown by the strong linear correlation between respiration and motility in untreated and caffeine-treated spermatozoa. In comparison with ejaculated spermatozoa investigated in a previous study, epididymal cells exhibited the same rates of uncoupled and ouabain-sensitive respiration. The efficiency of transforming mitochondrially-produced ATP into cell motion was the same in epididymal and ejaculated spermatozoa. The ATP-producing capacity of sperm mitochondria was utilized in untreated epididymal, in caffeine-stimulated epididymal and in ejaculated spermatozoa, by 20-25%, 40-45% and 45-50%, respectively. The results showed that the capacity of mitochondrial. ATP formation remains unchanged after ejaculation and is utilized to a higher extent by stimulated motility. Treatment with caffeine affected epididymal spermatozoa in a similar manner.
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PMID:Quantification of aerobic energy turnover in epididymal bull spermatozoa. 229 10

In cases of congenital absence of vas deferens (9 patients) or after failure of previous epididymovasostomy (2 patients), in vitro fertilization (IVF) was attempted with spermatozoa surgically obtained at the epididymal caput level. These sperm populations showed little progressive motility (5.9 +/- 6.5%) and an marked necrozoospermia (19.3 +/- 17.4%). Stimulation by caffeine (4.5 mM) alone or associated with heterologue normal seminal fluid resulted in most of the cases in an initiation of motility with an improvement of the progressive velocity. In 9 IVF attempts, 31 mature oocytes were inseminated with 5.10(3) to 1.5.10(6) motile spermatozoa. The dynamic characteristics in 3 inseminated sperm populations were Vp (24.2 +/- 8.3 microns/s), Ah (8.6 +/- 2.0 microns) at room temperature. Sperm binding to zona pellucida was decreased (0 to about 20 spermatozoa per oocyte) and there was no fertilization. In the same period, 21 attempts of intra uterine insemination and 14 attempts of intracervical inseminations were made in 5 couples who remained infertile after patent high epididymovasostomy (4) or vasovasostomy (1) and having immature spermatozoa stimulated as previously described. Antisperm antibodies were detected on the ejaculated spermatozoa in four men. No pregnancy was obtained with these immature stimulated spermatozoa. The fertility of the female partners was confirmed in 3 women after insemination with donor sperm.
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PMID:[In vivo and in vitro fertilizing ability of immature human epididymal spermatozoa]. 325 6

The highly selective fluorescent Ca2+ indicator 'quin 2' has been loaded into ram and boar spermatozoa as the acetoxymethyl ester, 'quin 2/AM', which is hydrolysed and trapped in the cytoplasm. Loadings of several mM were not toxic to spermatozoa as judged by motility. Fluorescence measurements (mean +/- S.E.M.) indicated a normal cytoplasmic free-calcium concentration, [Ca2+]i, of 193 nM +/- 0.2 (n = 10) for ejaculated ram sperm, 175 nM +/- 3.9 (n = 10) for cauda epididymal boar sperm and 105 nM +/- 10 (n = 10) for the caput sperm. After cold shock ejaculated ram and cauda epididymal boar sperm did not retain quin 2, due presumably to structural damage. However, cold shocked caput boar sperm could be readily loaded with quin 2 and had a [Ca2+]i similar to control sperm. Sodium azide, propranolol and caffeine did not affect the [Ca2+]i of ram and boar sperm, however theophylline, dibutyryl c-AMP and La3+ significantly reduced it. The inhibitors rotenone and antimycin A, and the uncouplers 2,4-DNP and CCCP caused a transient elevation of [Ca2+]i, most likely resulting from release of mitochondrial calcium. The increased [Ca2+]i following addition of the ionophore A23187, was highly pH dependent in ram spermatozoa and it was critical to increase the pH of the medium above 7.5; the increase in [Ca2+]i was apparently not dependent on the oxidative metabolism of the sperm as addition of the uncouplers 2,4-DNP and CCCP had no effect on [Ca2+ )i. Addition of filipin to ram and boar sperm resulted in a large increase in [Ca2+]i but addition of filipin to ionophore-treated sperm caused [Ca2+]i to fall well below control levels.
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PMID:Measurement and manipulation of cytoplasmic free calcium of ram and boar spermatozoa using quin 2. 335 80

The effect of chronic caffeine treatment on lipolysis in rat epididymal adipose tissue was studied. There was a decrease in body weight, epididymal fat pad weight and mean adipocyte diameter in caffeine-treated rats when compared with control rats. No difference in adipocyte triglyceride content or mean adipocyte weight between control and caffeine-treated rats was observed. Lipolysis in adipocytes induced by adenosine deaminase (1 U/ml) decreased by 35% in caffeine-treated rats. This was accompanied by a 2.5-fold increase in the anti-lipolytic potency of 2-chloroadenosine and an increase of adipocyte adenosine A1 receptor number.
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PMID:Potentiation of the anti-lipolytic effect of 2-chloroadenosine after chronic caffeine treatment. 340 45


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