Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carnitine and its short-chain acyl esters were assayed in semen from normospermic and azoospermic men. Extremely low concentrations of free carnitine and acylcarnitine were found in semen from patients with obstructive azoospermia where the ejaculate was primarily of prostatis origin, and low values were also obtained in obstruction of the vas deferens, where the epididymal contents were not ejaculated. Semen from patients whose azoospermia was caused by testicular dysfunction had low acylcarnitine concentrations and normal levels of free carnitine in most cases, but a group of patients with severe testicular failure (including cases of Klinefelter syndrome and cryptorchidism) had low semen free carnitine concentrations. Whereas treatment with human chorionic gonadotropin increased serum testosterone levels in azoospermic patients, it did not increase the free carnitine concentration in semen, although it increased the proportion of carnitine found in acylcarnitines.
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PMID:Carnitine and acylcarnitines in semen from azoospermic patients. 611 78

Data about the levels of free L-carnitine, an epididymal marker in human semen, are contradictory and unclear, particularly in their relationship to fertility. This can perhaps be explained by the absence of any studies of seminal L-carnitine in a large group of fertile men, and by the lack of consideration of factors influencing its secretion. In this study, free L-carnitine was determined using a spectrophotometric method in deproteinized semen samples from fertile (n = 162) and infertile men without azoospermia (n = 303). Our results can be summarized as follows: Infertile men were found to have significantly lower (P less than 0.001) seminal carnitine levels (755 +/- SD 499 nmoles) compared with fertile men (1010 +/- 570). Percentiles have been calculated for fertile men, and 'normal' values proposed (10th percentile = 390 and 90th percentile = 1830 nmoles). Distribution of the levels of L-carnitine were asymmetric in fertile as well as in infertile men (median: 922 nmoles vs 645). In both groups, a significant increase in carnitine levels was observed with increasing length of abstinence, and a decrease in the ratio of carnitine/days of abstinence. Methodological, physiological and pathological factors which may explain these results are discussed.
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PMID:Levels of seminal free L(-) carnitine in fertile and infertile men. 648 Jan 40

1. L-carnitine and its short-chain acyl derivatives were measured in semen of boar, man, rooster, bull, squirrel monkey and ram. 2. Carnitine was present in concentrations of 220, 476, 540, 1880, 3330 and 3820 muM respectively, and acetylcarnitine concentrations were 2, 191, 354, 709, 259 and 2750 muM. Propionyl and C4-acyl carnitines were found in small quantities. 3. Analysis of sequential "Split-ejaculate" samples of boar semen showed that carnitine concentration correlated with sperm count, suggesting an epididymal origin for this substance in this species. 4. Bioautographic analysis of samples obtained from ram and rat indicated that carnitine and acetylcarnitine were present in epididymal fluid and in fluids from accessory glands of the male reproductive tract.
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PMID:A comparative study of carnitine and acylcarnitine concentration in semen and male reproductive tract fluids. 712 5

Differences in the metabolism of testicular and cauda epididymal sperm have been demonstrated for several species, but the region(s) of the ram epididymis in which changes in metabolism occur is not known. In these experiments respirometric and radioisotopic methods were used to monitor metabolic activity of ram sperm isolated from six regions of the epididymis. Effects of exogenous carnitine on metabolism of the sperm also were studied. Sperm from the caput and corpus epididymidis had similar rates of glucose and oxygen consumption and of lactate and CO2 production. However, the magnitude of each parameter was severalfold higher for cauda sperm. In addition, cauda sperm produced 25 times more acetate than caput or corpus sperm. The amount of energy derived from utilization of endogenous substrates was similar for sperm from all regions of the epididymis. Exogenous D,L-carnitine (5 mM) had no effect on the metabolism of caput or corpus sperm. However, when cauda sperm were incubated with carnitine, they consumed less glucose and produced less lactate and more acetate; thus they produced the same amount of ATP from less glucose than did control aliquots incubated without exogenous carnitine. Since the rate of ATP synthesis was equivalent for both incubations, we believe this change in metabolism reflects an increased efficiency of glucose utilization. This increased efficiency may be vital for sperm motility.
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PMID:Changes in metabolism of ram sperm associated with epididymal transit or induced by exogenous carnitine. 713 17

The semen characteristics of 215 fertile men (F = fathers requesting vasectomy) and of 409 infertile men (I) have been analysed under strictly identical conditions. The mean values for volume, sperm concentration, and the percentages of motile, vital and morphologically normal spermatozoa were greater in group F than in I. Seminal variations were much greater in cases of testicular lesions (cryptorchidism, hypotrophy) than in varicocele, although there remains a difference between F and I even after exclusion of all clinical lesions suggesting a role for other factors in the origin of much cases of infertility. Other than in cases of azoospermia, there is no difference in the function of the accessory glands detectable by the assay of seminal biochemical markers: fructose (seminal vesicles) acid phosphatase and citrate (prostate); only L-carnitine (epididymal marker) is elevated in the fertile men, however this difference is only a reflection of the observed difference in sperm concentration in combination with the close correlation between sperm concentration and L-carnitine values.
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PMID:[Semen characteristics and fertility (author's transl)]. 734 Jun 97

Carnitine estimation in human semen is of diagnostic value for epididymal function. About 95% of the free carnitine originates from the epididymis. In patients with euspermia the median value of carnitine is 7 +/- 3 mg%. The clinical significance of carnitine determination is demonstrated in azoospermia, varicocele, and obstructive azoospermia. In order to obtain a general picture of seminal plasma we ought not to rely only on fructose estimations but should also take into account those of the citrate and carnitine.
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PMID:Carnitine in seminal plasma: its significance in diagnostic andrology. 736 39

The epididymis is the site of posttesticular sperm maturation in the male genital tract. Studies on human epididymides are hampered by the practical inaccessibility of epididymides of healthy men in their reproductive years. The limited use of laboratory animals therefore seems unavoidable. The objective was to establish baseline values of the epididymal markers alpha-glucosidase, glycerophosphocholine (GPC) and carnitine in the lumen of the caput, corpus and cauda epididymidis and in the ejaculate of adult male Chacma baboons and vervet monkeys. In both primates, alpha-glucosidase was found throughout the epididymis and in the ejaculate; values did not vary significantly. In monkeys, the highest concentration of GPC was found in the cauda epididymidis, but smaller amounts were found in the other regions and the ejaculate. In baboons, GPC was absent from the caput, but present in the other regions, including the ejaculate. Carnitine concentrations increased significantly from the caput to the cauda in monkeys and from the caput to the corpus in baboons. With this study, the relative concentration ranges in which these markers are present in the epididymides of these primates have been established. In future studies, changes in concentrations of these substances would probably indicate changes in epididymal function.
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PMID:The presence of alpha-glucosidase, glycerophosphocholine and carnitine in the epididymis and ejaculate of the vervet monkey (Cercopithecus aethiops) and the Chacma baboon (Papio ursinus). 748 36

Ornidazole (400 mg kg-1 day-1) given by oral gavage rendered male rats infertile by 6.6 +/- 0.7 days (mean +/- SEM, n = 9, range 3-10) after beginning the treatment and fertility returned within 5-10 days after treatment with ornidazole for 6-7 days. At 200 mg ornidazole kg-1 day-1, fertility was reduced but total infertility was not achieved. No differences were found in the percentage motility of spermatozoa recovered from any region of the epididymides of ornidazole-treated rats compared with controls. However, computer aided sperm analysis revealed significantly lower straight-line and average path velocities in ornidazole-treated animals (400 mg kg-1 day-1) for spermatozoa from the distal regions of the tract than for controls. Curvilinear velocity was significantly lower than that of controls in the distal corpus and cauda regions. The motility characteristics of spermatozoa from animals receiving 200 mg ornidazole kg-1 day-1 were lower than, but not significantly different from, motility in controls. There were no differences between the total protein, L-carnitine, glycerophosphocholine or total alpha-glucosidase content in epididymal homogenates from fertile control and infertile ornidazole-treated animals. Spermatozoa released from the cauda epididymidis of untreated rats into ornidazole solutions displayed no changes in the percentage motility up to 20 mmol l-1 and were only depressed at 50 mmol l-1. All velocities revealed a biphasic response with an initial increase in motility and then inhibition at higher concentrations, but a significant difference from velocities in the absence of orindazole was evident only for straight line velocity (VSL) at 50 mmol l-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of reversible infertility in male rats by oral ornidazole and its effects on sperm motility and epididymal secretions. 802 76

In the male reproductive tract, very high concentrations (mmol l-1) of free L-carnitine and acetyl-L-carnitine are found in the epididymides, seminal plasma and spermatozoa. It has been reported that the uptake of free L-carnitine by spermatozoa might be related to the epididymal maturation of the sperm membrane, since a greater uptake was found by caput than by cauda spermatozoa in vitro. However, the free L-carnitine concentrations estimated inside the gametes were never greater than those of the surrounding medium. In this study, we investigated the mechanism of transport of free L-carnitine and its ester acetyl-L-carnitine, through the plasma membrane of mature and immature epididymal boar spermatozoa. In vitro, we found a passive diffusion of both compounds to the spermatozoa, whatever the maturation stage. The spermatozoa might progress in the epididymal lumen and accumulate high amounts of free L-carnitine. The active uptake of free L-carnitine occurs only across epididymal mucosa. These results are in agreement with those reported on cells of other organs that exchange pharmacological free L-carnitine concentrations (mmol l-1) by a passive mechanism through the plasma membrane. The acetylation of high amounts of free L-carnitine inside the spermatozoa was found only in caudal spermatozoa. This result suggests that oxidative metabolism (producing acetyl CoA) might be more active in mature cells. The acetyl-L-carnitine added to the incubation medium of boar spermatozoa was hydrolysed. Enzymatic activity of the sperm membrane is low and this may partially explain the low concentrations of acetyl-L-carnitine found in the caudal epididymal plasma.
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PMID:Uptake and release of free L-carnitine by boar epididymal spermatozoa in vitro and subsequent acetylation rate. 818 99

This study was designed to examine whether short- and long-term treatments by a low level of dietary L-carnitine are capable of altering enzyme activities related to fatty acid oxidation in normal Wistar rats. Under controlled feeding, ten days of treatment changed neither body weights nor liver and gastrocnemius weights, but succeeded in reducing the weight of peri-epididymal adipose tissues. Triacylglycerol contents were lowered in liver and ketone body concentrations were found slightly more elevated in blood. In the liver, mitochondrial carnitine palmitoyltransferase I (CPT I) exhibited a slightly higher specific activity and a lower sensitivity to malonyl-CoA inhibition, while peroxisomal fatty acid oxidizing system (PFAOS) was found to be less active. Carnitine supplied for one month reduced the mass of the periepididymal fat tissue, but not those of the other studied organs, and produced a slight but non-significant gain in body weight after ten days of treatment. In the liver, CPTI characteristics were comparable in control and treated groups, while PFAOS activity was less in rats receiving carnitine. Data show that L-carnitine at a low level in the diet exerted two paradoxical effects before and after ten days of treatment. Results are discussed in regard to fatty acid oxidation in mitochondria and peroxisomes, and to the possible altered acyl-CoA/acylcarnitine ratio with increased concentrations of L-carnitine in the liver.
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PMID:Effect of short- and long-term treatments by a low level of dietary L-carnitine on parameters related to fatty acid oxidation in Wistar rat. 855 64


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