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)

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.
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PMID:Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia). 129 28

The secretion of epididymal proteins and their binding to spermatozoa in rats were examined after retrograde perfusion of the superior and inferior epididymal arteries with [35S]methionine. PAGE revealed that the pattern of radioactive proteins in the luminal fluid was markedly different from the well-characterized pattern of secretory proteins obtained by in vitro incubation of epididymal minces with labeled methionine. Of the proteins secreted into the lumen, about 1% were associated with Percoll-purified spermatozoa. More proteins were associated with the spermatozoa in the corpus epididymidis than in the caput. Sequential extraction of spermatozoa with an isotonic buffer, a high-salt buffer, Triton X-100, and SDS revealed that almost half of the radiolabeled proteins could be extracted with the isotonic buffer. The firmly bound radioactive proteins remaining, which were extracted with Triton X-100 or SDS, consisted of one major band of 25 kDa and two minor bands of 30 kDa and 32 kDa. Analysis of the sperm-associated proteins at various times after the isotope was administered indicated that tight binding of proteins to spermatozoa occurs within 3 h after isotope injection.
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PMID:Binding of epididymal proteins to rat spermatozoa in vivo. 139 46

Lipoprotein lipase (LPL) is an enzyme found in adipose tissue that is important in the hydrolysis of triglyceride rich lipoproteins, and in the uptake of FFA lipid into the adipocyte. To examine the effects of glucocorticoids on adipose tissue LPL, male Sprague-Dawley rats were injected with dexamethasone (1 mg/kg) every other day for 10 days, followed by measurement of LPL in epididymal adipose tissue. Compared to sham-injected controls, heparin-releasable LPL activity and LPL mass in the dexamethasone-treated rats were 44% and 62% of those in control rats, respectively. Adipocytes were prepared from the fat pads and pulse labeled with [35S]methionine, demonstrating a decrease in the LPL synthetic rate in the treated rats to 57% of the rate in control rats. In addition, LPL mRNA was quantitated by Northern blotting, demonstrating a decrease in LPL mRNA in the dexamethasone-treated rats. A simultaneous decrease in the message for gamma-actin was also noted. To examine the effects of dexamethasone on LPL in vitro, adipocytes were prepared from normal rats and treated with dexamethasone for 24 h in vitro. Dexamethasone decreased heparin-releasable LPL activity in cultured adipocytes to 40 +/- 6% of the control value (P less than 0.01). This decrease in LPL activity was accompanied by a decrease in the LPL synthetic rate using [35S]methionine labeling, to 33% of the control value, and no specific change in LPL turnover or secretion. In addition, dexamethasone added to adipocytes decreased LPL mRNA levels. Because the combination of insulin plus dexamethasone has been shown to yield synergistic increases in LPL in adipose tissue pieces, insulin was added to isolated adipocytes in combination with dexamethasone. Whereas insulin and dexamethasone individually had opposite effects on LPL, the combination of insulin plus dexamethasone resulted in no change in any aspect of LPL gene expression. Thus, dexamethasone resulted in a decrease in adipocyte LPL mRNA levels both when added to cultured adipocytes in vitro as well as when injected into rats. This decreased LPL mRNA level yielded corresponding changes in the LPL synthetic rate and LPL activity.
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PMID:The regulation of lipoprotein lipase gene expression by dexamethasone in isolated rat adipocytes. 154 42

Lipoprotein lipase (LPL) is an important enzyme in lipid metabolism, and adipose LPL activity is increased in rats that are deficient in thyroid hormone. To examine the mechanism of thyroid hormone's effect on LPL, LPL gene expression was assessed in the epididymal fat pads of hypothyroid rats. When compared to control rats, LPL activity, mass, and synthetic rate in hypothyroid rats were increased; heparin-releasable LPL activity and mass were increased to 448% and 300% of control, respectively, and [35S]methionine incorporation into LPL was increased to 250% of control. The increases in LPL activity and mass were reversed by treatment of hypothyroid rats with triiodothyronine (T3). However, there was no change in the level of LPL mRNA when compared to the level of gamma-actin mRNA and no effect on LPL transcription using run-off assays. Isolated adipocytes were prepared from normal rats and exposed to 2 nM T3 in vitro for 24 h. The addition of T3 to cultures of adipocytes resulted in a decrease in LPL activity, mass, and [35S]methionine incorporation, but still no change in LPL mRNA level. To determine whether thyroid hormone regulated catecholamine responsiveness, adipocytes were prepared from hypothyroid and control rats, and the responses to epinephrine were compared. Although epinephrine inhibited [35S]methionine incorporation into LPL in control rat adipocytes, there was essentially no effect in hypothyroid rat cells. In addition, T3 treatment of the hypothyroid rats restored the responsiveness to epinephrine. Thus, thyroid hormone regulates LPL in rat adipose tissue posttranscriptionally, resulting in parallel changes in LPL synthetic rate, immunoreactive mass, and activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of adipose tissue lipoprotein lipase gene expression by thyroid hormone in rats. 156 76

The synthesis and secretion of proteins in the different regions of the human epididymis were studied in vitro. Epididymal tissues obtained from patients undergoing castration for prostatic carcinoma or from cadavers were incubated in the presence of [35S]methionine, and the resulting radiolabeled proteins were analysed on SDS-PAGE. The corpus region was found to be the most active segment in total protein synthesis. Significant qualitative and quantitative changes were observed in the pattern of proteins secreted from the different epididymal regions. To establish those epididymal proteins that interact with maturing sperm, the secreted products were immunoreacted with antibodies raised against a Triton X-100 extract of ejaculated human sperm heads. The antibodies react mainly with the head region of ejaculated spermatozoa as judged by indirect immunofluorescence. Protein A-gold labeling of freeze-fracture images showed gold particle distribution on the sperm plasma membrane. Western blot analysis of the secreted proteins revealed four bands (66, 37, 32, and 29 kDa) in the proximal regions and six additional bands (80, 76, 48, 27, 22, and 17 kDa) in the distal part of the epididymis. Immunoprecipitation of the secreted proteins with these antibodies revealed six radioactive bands of 170, 80, 76, 60, 48, and 37 kDa, which indicates that certain proteins of epididymal origin bind to the sperm plasma membrane.
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PMID:Protein synthesis and secretion in the human epididymis and immunoreactivity with sperm antibodies. 234 42

The presence of epididymal secretory proteins in crude luminal fluids of the epididymis of mice was investigated at varying times after i.v. injection of 35S-methionine or after incubation of epididymal minces with 35S-methionine. The amount of label incorporated into luminal proteins after in vivo injection was not significantly different at 4, 8, 12, and 16 h. The quantity of labeled proteins in the crude luminal fluids of Regions 1-3 (caput) was about two and four times higher than in Regions 4 (corpus) and 5 (cauda), respectively. Increasing the dosage of 35S-methionine strongly increased the amount of labeled protein present. Approximately half of the labeled protein present in the epididymis was found in the luminal fluid. Polyacrylamide gel electrophoresis revealed comparable patterns of proteins at 8 h after injection of isotope or after a 5-h in vitro incubation of minced epididymal tissues with isotope. The protein patterns from the five regions, however, were markedly different from each other and highly characteristic. Two proteins (25 kDa and 18 kDa) were found in crude luminal fluids of Regions 2 and 3 eight hours after in vivo injection, but not in Regions 4 and 5. One protein (29 kDa) was found in high amounts in Regions 4 and 5 eight hours after injection. Five days after injection, the three proteins were found in Regions 4 and 5. However, the 25-kDa protein was present in reduced amount, whereas the 18- and 29-kDa proteins accumulated in caudal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Secretion and transport of mouse epididymal proteins after injection of 35S-methionine. 239 84

The sequential interactions of epididymal secretory proteins with spermatozoa during epididymal transit were examined. Mice received injections of 35S-methionine, and the radiolabeled luminal fluid and sperm-associated proteins were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis at various times after injection. The majority of the luminal fluid and sperm-associated proteins were found in the caput epididymidis at 8 h; by 7 days, many of these proteins had been transported to the cauda epididymidis. Two classes of epididymal protein-sperm interactions were distinguished on the basis of regional synthesis and secretion. The major class consisted of proteins that were synthesized, secreted, and bound to spermatozoa in the caput epididymidis. In this class, however, the binding of proteins to the spermatozoa was variable. For example, a protein of 25 kDa remained associated with spermatozoa in substantial amounts during epididymal transit, while proteins of 40 and 35 kDa decreased in amount. Other proteins such as a protein of 18 kDa did not remain associated with spermatozoa. Another class of proteins (54, 44, 29 kDa) were synthesized and secreted from all epididymal regions but bound only to caput spermatozoa. Most of the epididymal proteins appeared to be tightly bound to the spermatozoa since spermatozoa already saturated with the unlabeled protein in the distal epididymis remained so even though the spermatozoa were surrounded by labeled proteins in the luminal fluid. These studies demonstrate that a variety of specific interactions occur between epididymal secretory proteins and spermatozoa as they migrate and mature in the epididymis.
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PMID:Interactions of labeled epididymal secretory proteins with spermatozoa after injection of 35S-methionine in the mouse. 239 85

A glycoprotein, designated CMB-1, has been identified in media from Sertoli cell-enriched cultures that increases in concentration in response to follicle-stimulating hormone (FSH) and testosterone. Subsequent studies indicated that CMB-1 is immunologically related to albumin and alpha-fetoprotein and is concentrated in the luminal compartment of the testis in adult rats. Thus, CMB-1 was termed testibumin. The goal of the present study was to determine the concentrations of this protein in testes, epididymides, and serum of normal rats between 10 and 180 days of age and to compare them to rat androgen-binding protein (rABP). Testibumin concentration in rat testes increased with age and peaked at Day 60; thereafter, unlike rABP, its concentration declined, reaching a plateau by 150 days of age. Testibumin concentration in the epididymal compartment also increased with age and peaked at Day 90; thereafter, its concentration remained relatively unchanged. Unlike rABP, which accumulates in the caput epididymis, testibumin did not accumulate preferentially in any particular region of the epididymis. In spite of the marked changes of testibumin concentration in the male reproductive tract, the levels in blood remained relatively constant between 10 and 180 days of age. In adult male and female rats, the serum concentrations of testibumin were similar. Following orchiectomy, serum testibumin concentration decreased by 50% with an apparent t1/2 of approximately 8 h. The presence of immunoreactive macromolecules in other species that share epitopes with rat testibumin was also investigated. Material in human sera and extracts of human and monkey testes cross-reacts with rat testibumin. After [35S]methionine was added to the primary Sertoli cell-enriched cultures, anti-testibumin antiserum selectively immunoprecipitated a radiolabeled protein with the same electrophoretic mobility as purified testibumin on sodium dodecyl sulfate (SDS)-polyacrylamide gels. We conclude that 1) rat testibumin is synthesized and secreted by Sertoli cell-enriched cultures; 2) the relative concentrations and distribution of testibumin in testis, epididymis, and serum of the rat as a function of age are strikingly different from those of rABP; 3) rat testibumin shares epitopes with proteins in human serum and testicular extracts of monkey and man.
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PMID:The distribution of rat testibumin in the male reproductive tract. 244 71

To obtain evidence of a physiological role for androgens and estrogens in the regulation of the epididymis of sexually immature rabbits, the effects of these hormones on [35S] methionine incorporation into epididymal proteins in vitro were examined. Two-dimensional polyacrylamide gel electrophoresis revealed that short term incubation with estradiol changed the patterns of radiolabeled proteins detected in tissue homogenates of epididymal segments from castrated rabbits compared to those in segments from castrated rabbits that were not exposed to exogenous estradiol. Most of the changes seen in corpus tissue affected proteins with a wide range of pI values and relatively high mol wt (greater than 40K). The effects on caput and cauda tissue proteins were seen over a wide pH and mol wt range. Castration abolished many of the regional differences in protein synthesis; these were restored by incubation with estradiol. Testosterone had little effect on the synthesis of tissue proteins, except for stimulation of the synthesis of a single protein (17K; pI 5.1) in all three segments and stimulation of a small group of proteins (less than 14K; pI 7.0-7.2) in the corpus. Estradiol had little effect on proteins secreted by epididymal segments. Testosterone, however, stimulated the synthesis of a number of unique proteins secreted by the caput and corpus and resulted in a pattern of radiolabeled proteins similar to that obtained with intact animals. Additional secretory proteins could be stimulated in caput, but not corpus, tissue minces from intact rabbits by exogenous testosterone. No androgen-specific synthesis of secretory proteins was detected in the cauda of either castrated or intact rabbits. Estradiol affected the synthesis of both secreted and tissue proteins in terms of influencing which epididymal segment was most active at incorporating [35S]methionine into radiolabeled proteins and which was least active. Testosterone had a similar influence on secreted proteins, but did not have any analogous effect on tissue proteins. These results indicate that testosterone and estradiol influence the synthesis of proteins by the immature rabbit epididymis and that both may, therefore, be important physiological regulators of epididymal development and/or function.
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PMID:Estrogen and androgen regulation of protein synthesis by the immature rabbit epididymis. 273 45

The effects of castration and hormone replacement on [35S]methionine incorporation into newly synthesized proteins by the adult rabbit epididymis were studied in vitro. The proteins were analyzed using two-dimensional polyacrylamide gel electrophoresis. Short term (4-day) castration resulted in a few changes in the pattern of radiolabeled proteins observed in the caput, but no effect was seen in the corpus or cauda. The changes in the caput could be reversed if the samples were incubated with testosterone. The epididymis of short term castrates failed to respond to exogenous estradiol. Long term castration (4-6 weeks) resulted in changes in protein synthesis among all three epididymal segments. Short term (4-h) incubation with testosterone restored the pattern of proteins secreted by the caput and cauda to that in intact rabbits. Short term incubation with estradiol did not restore the pattern of radiolabeled secreted proteins, but it did slightly intensify a 28K protein (pI 5.2) that was present in the caput and cauda of castrated animals. No clear-cut effect of the hormones on proteins secreted by the corpus was observed. Short term incubation with testosterone or estradiol restored the patterns of tissue proteins synthesized by the caput and corpus of castrated rabbits to that in intact animals. In the cauda, estradiol also enhanced the presence of a small group of high mol wt proteins present in the control castrate sample, while testosterone inhibited these proteins. This group of proteins was absent in cauda tissue samples from intact rabbits.
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PMID:Androgen and estrogen effects on protein synthesis by the adult rabbit epididymis. 273 46


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