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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We estimated nucleotide pyrophosphatase and phosphodiesterase I activities in human and rat organs and in body fluids from man and dog. The highest organ activities were found in epididymis, kidney, liver, and intestine. In body fluids, the activity was highest in seminal plasma, followed by intestinal lymph, serum, heart lymph, cerebrospinal fluid, milk, and urine. The ratio nucleotide pyrophosphatase/phosphodiesterase I and the urea resistance of phosphodiesterase I differed among human organs, body fluids, and blood cells. Different isoenzymes probably exist. The activities in serum share several properties with those in several organs--e.g. pH-optimum 9.6-9.8, dependency on Zn2+, and the effects of inhibitors. Phosphodiesterase I in erythrocytes, which has not been described previously, differs from enzyme from other sources by lower pH optimum (8.5), dependency on Mg2+, inhibition by Zn2+, and stimulation by dithiothreitol.
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PMID:Nucleotide pyrophosphatase and phosphodiesterase. I. Organ distribution and activities in body fluids. 1 63

The activity of 5'-nucleotidase (EC 1.3.5), cyclic nucleotide phosphodiesterase (EC 2.1.4.17), non-specific phosphodiesterase (EC 3.1.4.1) and ribonuclease (EC 1.7.7.16)has been investigated in the seminal plasma of whole semen and in the secretions of the seminal vesicle, prostate and epididymis of the bull, boar, ram, stallion, jackass, rabbit and man. Bull seminal plasma showed the highest activity for 5'-nucleotidase, cyclic nucleotide phosphodiesterase and ribonuclease; in contrast, stallion and jackass semen were very poor in these enzymes. Ram, rabbit and boar seminal plasma showed intermediate levels for all enzymes studied. In the bull and ram, nucleolytic enzymes were found to be secreted by the seminal vesicles but in the boar, rabbit and stallion they originate mostly from the epididymis. In human seminal plasma all of the enzymes studied exhibited activity but the levels were generally lower than those recorded for the other species.
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PMID:The activity of some nucleolytic enzymes in semen and in the secretion of the male reproductive tract. 19 15

The activities of the low-Km and high-Km forms of cyclic AMP phosphodiesterase (PDE) were determined in extracts prepared from epididymis and prostate taken from adult (10-12 months) and from aged (32-35 months) rats. The maximum velocity V of low-Km PDE in the epididymis of normal adult rats (approx. 300 pmoles/min per mg protein) was increased after castration by 80%, whereas V of the high-Km form remained unchanged, suggesting that only the low-Km PDE is subject to regulation by the animals' endocrine status. In the epididymis of aged rats V of low-Km PDE was unchanged, whereas V of high-Km PDE (approx. 3000 pmoles/min per mg protein) was decreased by 40%; in the prostate of aged rats V of both low-Km (approx. 225 pmoles/min per mg protein), and of high-Km PDE (approx. 1500 pmoles/min per mg protein) were decreased by 50-60%. The absence of interdependence of the two forms of the enzyme in their response to changes in environmental conditions in each organ suggests different mechanisms of control of their activities and adds validity to the reported age-related decline of low-Km-PDE activity in prostate.
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PMID:Cyclic adenosine 3',5'-monophosphate-phosphodiesterases in epididymis and prostate of castrate and of aged rats. 283 70

Six different monoclonal antibodies were generated after immunization of mice with a partially purified enzyme preparation of rat liver, containing nucleotide-sugar hydrolase (NSH) I and II. These enzymes are also known under the names phosphodiesterase I and CMP-sialic acid hydrolase respectively [11]. In the enzyme-immunoassay the antibodies directed against NSH I displayed some cross-reactivity with the enzyme preparation of NSH II, and to a much lower extent the reverse was also true. Two antibodies, C and D highly reactive with NSH II and NSH I respectively, were used for immunocytochemical studies on sections of various rat tissues, which were known to contain high activities of both enzymes. Both antibodies were shown to be highly specific domain markers for different sides of the various cells. Antibody C was bound exclusively to the sinusoidal side of liver hepatocytes and to the basal side of cells from kidney tubule and epididymis. For antibody D the binding pattern was completely different, showing exclusive binding to the canalicular side of the hepatocytes and to the brush border membranes of kidney tubule cells, whereas in epididymis only binding to connective tissues was observed. Our studies clearly demonstrate, at least for liver and kidney, that NSH I and II are located at different cellular sides and that the monoclonal antibodies C and D can be used as domain markers for basal and apical sides of these cells respectively.
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PMID:Detection of different cellular sides in rat liver and kidney by two monoclonal antibodies raised against the nucleotide-sugar hydrolyzing enzymes phosphodiesterase I and CMP-sialic acid hydrolase. 298 96

8-Azido cAMP photoaffinity labeling of cAMP-dependent protein kinase regulatory subunits (R1 = 49 K;R2 = 55K) was done on spermatozoa from species lacking, and species containing an epididymis. Spermatozoa from sea urchin and trout contained only R1, while rat caudaepididymal spermatozoa contained both R1 and R2 subunits. This was established by the Mr value of the 8-azido cAMP photolabeled moieties, and a biochemical analysis based on the known differences of protein-nucleotide interactions of Type I and II cAMP-dependent protein kinases. Sea urchin and trout sperm R1 subunits were similar to mammalian sperm R1 subunits in co-migration on SDS-polyacrylamide gels and in both saturation and specificity of nucleotide binding. Calcium enhanced photoprobe binding to rat R1 and R2 subunits and to sea urchin R1 subunit without revealing a sea urchin R2 subunit. Likewise, phosphodiesterase incubation of sea urchin and trout spermatozoa prior to photolabeling did not reveal R2 subunits. These data suggest that the cAMP regulation of sperm physiology may require R1 subunit in species both with and without an epididymis. Further taxonomic study is necessary to determine whether evolutionary acquisition of the epididymis and internal fertilization may have created unique environments favoring the addition of sperm R2 regulatory subunits of cAMP-dependent protein kinase.
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PMID:A comparative analysis of cAMP-dependent protein kinase regulatory subunits in sea urchin and rat spermatozoa. 299 17

Phosphodiesterase I (PDE I) is an exonuclease capable of hydrolyzing a variety of phosphate ester and pyrophosphate bonds. Cell fractionation and histochemical studies in animal tissues have localized PDE I in the plasma membrane of various epithelia. This suggests a role for the enzyme in active transport. Distribution of PDE I in human tissues has not previously been studied. We have produced a polyclonal antiserum to bovine intestinal PDE I and have demonstrated crossreactivity with the human intestinal enzyme. This polyclonal antiserum was used in PAP immunocytochemistry to localize immunoreactive PDE I in a variety of human tissues. Localization was prominent in the gastrointestinal tract, including the cytoplasm of gastric mucosa parietal cells, cytoplasm of surface epithelium and isolated crypt cells in small intestine, and the colonic epithelial cytoplasm and brush border. Parotid gland acinar cells and scattered ductal cells showed positive cytoplasmic staining. Acinar and scattered pancreatic islet cells contained immunoreactive PDE I, as did Kupffer cells of the liver sinusoids. Immunoreactive PDE I was found in all vascular endothelia. The epithelium of the urinary tract showed extensive immunoreactivity. This included the distal convoluted and collecting tubules of the kidney, and ureteral and bladder urothelium. In previous histochemical studies of animal tissues, no evidence of PDE I activity was noted in male or female reproductive tract. In this study, immunoreactive PDE I was localized to human Sertoli cells and to basal epithelium of the epididymis and prostate acini. Fallopian tube epithelium of female reproductive tract also demonstrated immunoreactive PDI I, as did several cell types in term placenta. Our immunocytochemical results with human tissues differ significantly from previous histochemical studies in animal tissues, principally in the genitourinary system. This may be due in part to the different detection systems employed as well as the higher sensitivity of the immunoperoxidase technique. This underscores the importance of adjunct techniques in tissue surveys. The widespread epithelial distribution of immunoreactive PDE I detected by this polyclonal antibody implies an integral role in cell function, probably in active transport.
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PMID:Distribution of phosphodiesterase I in normal human tissues. 302 90

Lizard spermatozoa, which are non-motile in the testis, develop the ability to swim as they pass along the excurrent duct. The addition of caffeine, a phosphodiesterase inhibitor, induced forward motility in spermatozoa from the caput epididymidis and increased the velocity of spermatozoa from the distal part of the epididymis. Caffeine had no effect on the motility of testicular spermatozoa. This suggests that sperm motility in this species is cyclic AMP-dependent but this factor alone is not sufficient to induce testicular sperm motility. In samples from the distal region of the epididymis, sperm motility was maximal in April just after the breeding season and then decreased significantly during the following months. A parallel can be drawn between these data and the levels of testosterone in the plasma. In the lizard, as in mammals, the epididymis may play an important role in the maturation of spermatozoa.
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PMID:Acquisition of sperm motility and its maintenance during storage in the lizard, Lacerta vivipara. 402 Jul 69

Three different preparations of relaxin elevated cAMP levels in isometrically suspended uterine strips obtained from estrogen-primed female rats in the presence of phosphodiesterase inhibitors. The effect was time and dose dependent, with maximal response at 20 min and 1 microgram/ml, respectively. No changes in cGMP levels were observed. No significant response was observed in ileum, vas deferens, epididymis, or testicular capsule. In the absence of phosphodiesterase inhibitors, relaxin markedly suppressed spontaneous contractile activity at doses of 0.36 and 0.96 microgram/ml but did not elevate cAMP in this dose range. While the beta-adrenergic antagonist propranolol suppressed both the relaxant action and cAMP stimulation promoted by isoproterenol, it did not interfere with the effect of relaxin on these same parameters. Relaxin is therefore capable of relaxing uterine muscle and elevating cAMP by mechanisms which probably do not require beta-adrenergic mediation. It is not clear at present whether the effects of relaxin on cAMP levels and contractile activity are causally related.
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PMID:The interaction of relaxin with the rat uterus. I. Effect on cyclic nucleotide levels and spontaneous contractile activity. 624 46

This paper deals with findings implying the existence of an androgen-dependent phosphodiesterase (PDE) activity in accessory sexual glands (seminal vesicle and epididymis) of the rat. It is suggested that the PDE activity is not a prerequisite for, but merely a modulator of the overall androgenic response.
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PMID:Evidence for androgen-dependent phosphodiesterase activity in rat seminal vesicle and epididymis. 625 91

When rats were injected with the progestin ethynodiol diacetate in doses that suppressed spermatogenesis and the growth of accessory sex glands, the level of phosphodiesterase in epididymal and prostate tissues increased 5- to 10-fold. This increase was prevented by concurrent administration of testosterone propionate. A similar increase in phosphodiesterase activity was observed in the epididymides and prostates of castrated animals, with reversal by treatment with androgen. In immature rats approaching puberty, the phosphodiesterase activity in epididymis and prostate increased while the blood testosterone level remained low; as the testosterone level rose with the onset of puberty, the phosphodiesterase activity decreased. Incubation of enzymically active extracts of accessory tissues from castrated rats with heat-treated extracts of the corresponding normal tissues resulted in strong inhibition of the initially high phosphodiesterase activity. The addition of heat-treated extracts of accessory glands from castrated rats to enzymically active extracts of the corresponding tissues from normal rats resulted in a marked elevation of their phosphodiesterase activities. Of the two heat-stable modulators, the inhibitor factor was dialyzable. The dependence of this factor on testosterone suggests a mechanism of action by which the steroid hormone, by inducing the production in its target tissues of an inhibitory modulator of phosphodiesterase, controls the maintenance of functional levels of cAMP.
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PMID:Androgen control of an inhibitory modulator of phosphodiesterase in rat epididymis and prostate. 625 8


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