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1.
Effect of prostaglandin F2α on propulsive activity of the isolated segmental colon of the guinea-pig
The effects of prostaglandin F2α (PGF2α) on propulsive activity in segments of isolated colon and on isolated strips of guinea-pig colon were investigated.Using experimental conditions under which spontaneous propulsive activity was negligible, PGF2α (5×10−8×1×10−6M), added to the bathing medium, increased propulsive activity in a concentration dependent manner. This increase of propulsive activity was abolished in the presence of atropine or tetrodotoxin (1×10−7g/ml).The contractions produced by PGF2α(5×10−7 − 1×10−5M) in isolated longitudinal and circular smooth muscle strips of guinea-pig colon were unaffected in the presence of atropine or tetrodotoxin (1×10−7g/ml).From these results it is concluded that under the conditions employed in this study propulsive activity stimulated by PGF2α may depend on the contractions of both muscle layers and stimulation of the peristalic reflex. 相似文献
2.
Rungruedee Thiwthong Michihiko Kataoka Akira Iwasaki Hiroshi Watanabe Junzo Hasegawa Kimiyasu Isobe Sakayu Shimizu 《Microbial biotechnology》2008,1(5):395-402
Pseudomonas sp. MX‐058 produces aldehyde oxidase catalysing glyoxal to glyoxylic acid. Two aldehyde oxidases (F10 and F13) were purified to homogeneity from Pseudomonas sp. MX‐058. F10 and F13 had subunit structures, a heterotetramer and heteropentamer respectively. The N‐terminal amino acid sequences of all subunits were highly homologous to amino acid sequences of the putative oxidoreductases of Pseudomonas strains. All of these homologous oxidoreductases have a heterotrimer structure consisting of 85‐88 (α), 37‐39 (β) and 18‐23 (γ) kDa subunits. However, the α‐subunits of F10 and F13 might have decomposed into two [80 (α1) and 9 kDa (α2)] and three [58 (α1′), 22 (α1″) and 9 (α2) kDa] subunits, respectively, while the β‐ and γ‐subunits remained intact. Both F10 and F13 show high activity toward several aliphatic and aromatic aldehydes. The aldehyde oxidases of Pseudomonas sp. MX‐058 has unique protein structures, α1α2βγ for F10 and α1′α1″α2βγ for F13, a heterotetramer and heteropentamer respectively. The enzymes exhibit significantly low activity toward glyoxylic acid compared with glyoxal, which is an advantageous property for glyoxylic acid production from glyoxal. 相似文献
3.
4.
Pregnant hamsters were administered (SC) prostaglandin or vehicle on the morning of the 4th day of pregnancy. Serum progesterone was significantly depressed (p<.01) at 0.5, 2, and 6 hours after treatment with 100 μg PGF2α. Serum progesterone levels were unchanged 2 hours and 6 hours after treatment with 100 μg PGF2β and 2 hours after treatment with 1 mg PGF2β. Progesterone levels were depressed to less than 1 ng/ml 6 hours after treatment with 1 mg PGF2β. The specific uptake of 3H-PGF2α in whole hamster corpora lutea was significantly depressed 2 hours and 6 hours following 100 μg PGF2α treatment. A 15% depression in specific uptake occurred 0.5 hour post-treatment. Treatment with 100 μg PGF2β resulted in no change. Administration of 1 mg PGF2β resulted in depressed 3H-PGF2α uptake at both 2 and 6 hours post-treatment.Prostacyclin (PGI2) treatment resulted in no change in either 3H-PGF2α specific uptake or serum progesterone 2 hours after 100 μg treatment SC. These parameters were both reduced approximately 30% 6 hours post-treatment. Treatment with 6-keto-PGF1α resulted in a complete lack of measurable 3H-PGF2α uptake and serum progesterone levels less than 1 ng/ml at both 2 and 6 hours after treatment with 1 mg SC. 相似文献
5.
Intact viable bovine luteal cell suspensions prepared by collagenase digestion of luteal tissue were used in studying the selected properties of [3H] prostaglandin (PG) F2α binding and compared with those observed in plasma membranes. [3H]PGF2α specific binding to luteal cells was a rapid (K1 = 8.4 × 104M?12αS?1), reversible (K?1 = 1.8 × 10?4S?1) and saturable process at 24°. There was a single class of receptors with an apparent dissociation constant of 10.6 nM and 1.8 × 105 receptors per cell. The presence of increasing amounts of unlabeled PGs inhibited [3H]PGF2α binding in a dose-dependent manner. The potency order for this inhibition was: (15S) 15-methyl-PGF2α methyl ester > ICI-80,996 > PGF2α > ICI-81,008 > PGF1α > PGE2, (15S) 15-methyl-PGE2 methyl ester > PGF2α metabolites > other PGs, PGF1α metabolites and PGE metabolites. Other than the homegeneous nature of binding and a greater association rate in cells, the rest of the [3H]PGF2α binding properties in cells were in good agreement with those observed in plasma membranes. 相似文献
6.
J.M. Katz T. Wilson S.J.M. Skinner D.H. Gray 《Prostaglandins & other lipid mediators》1981,22(4):537-551
Mouse calvaria were maintained in organ culture for 96 h and endogenous prostaglandin production and active bone resorption (45 Ca release) measured. After a lag phase of 12 h, active resorption increased over the 96 h period. The amounts of prostaglandins released into the culture medium (measured by radioimmunoassay) were highest in the first 24 h of culture. Unless these were removed by preculturing for 24 h, or suppressed by indomethacin, no response to exogenous PGE2, PGF2α or prostaglandin precursors could be demonstrated. Bone resorption was stimulated after preculture by both PGE2 and PGF2α in a dose-dependent manner (10?18M – 10?5M), with PGE2 being the more potent. Collagen synthesis was unaffected by PGF2α, whereas PGE2 (10?5M) had an inhibitory effect. Eicosatrienoic acid did not stimulate bone resorption at lower concentrations (10?7M – 10?5M_, but was inhibitory at 10?4M. Arachidonic acid also inhibited resorption at 10?4M, but at lower concentrations (10?7M – 10?5M0 increased active resorption. This was concomitant with a rise in PGE2 and PGF2α levels, PGE2 production being significantly higher than PGF2α. The effects of PGE2 (10?8M) and PGF2α (10∞M appeared additive: there was no evidence of synergistic or antagonistic effects when varying ratios of PGE2 : PGF2α were employed. 相似文献
7.
D. J. Orlicky M. Silio C. Williams J. Gordon L. E. Gerschenson 《Journal of cellular physiology》1986,128(1):105-112
Stimulation of cultured rabbit endometrial cells by one of the rabbit endometrial cell culture proliferation factors, prostaglandin F2α (PGF2α), resulted in a very rapid increase in the intracellular levels of [3H]-inositol triphosphate (IP3), [3H]-inositol biphosphate (IP2), and [3H]-inositol monophosphate (IP1) in cells prelabeled with [3H]-inositol. These increases in inositol phosphate levels were detected in periods of stimulation as short as 30 seconds, reached a maximum by 1 1/2?2 min and declined to control levels by 6–10 min. The stimulation was dose-dependent with maximal increases observed near 10?6 M PGF2α. The cholinergic agent, carbachol, also led to time and dose-independent increases in IP3. Lithium, cadmium, silver, copper, and zinc ions had no effect either on the breakdown of IP3 or on the accumulation of IP1. In contrast, vanadate at 10?6 or 10?5 M did lead to a decrease in the breakdown of IP1 and a concomitant increase in IP1, IP2, and IP3. PGF2α was found previously to induce an increase in rabbit endometrial cell DNA synthesis which was inhibited by concomitant or prior addition of prostaglandin E1 (PGE1). PGE1, in a dose-dependent manner, was found to inhibit the observed IP3 increase by PGF2α at 1 1/2 min of stimulation. PGF2α treated and control cultures did not differ in cAMP or cGMP levels, cellular 45Ca uptake, nor cellular 22Na uptake. We propose that IP3 may be one of the intracellular messenger(s) synthesized following the treatment of rabbit endometrial cell cultures with the proliferation agent PGF2α and that it may play a crucial role with cAMP in growth regulation. 相似文献
8.
M Lahav A Freud H R Lindner 《Biochemical and biophysical research communications》1976,68(4):1294-1300
Corpora lutea explanted from rats on the sixth day of pregnancy responded to luteinizing hormone (LH; 5 μg/ml) in vitro with a two- to five-fold increase in cellular cyclic AMP (cAMP) concentration. The maximal cAMP level was reached within 60 min and maintained to the end of the 2 hr-incubation. On incubation with prostaglandin F2α (PGF2α) in addition to LH, this rise in cAMP accumulation was prevented. For significant suppression, 1.4 × 10?5M PGF2α was required. In the absence of LH, PGF2α (4.2 × 10?5M) caused no change in cellular cAMP. Addition of PGF2α (4.2 × 10?5M) to the incubation medium after the maximal response to LH was attained, caused the cAMP concentration to return to its basal level within 15 min. This abrogation of LH-stimulated cAMP accumulation represents the earliest and hence possibly the triggering event in PGF2α-induced luteolysis. 相似文献
9.
The unconjugated N-glycans Manα1→6(Manα→3)Manα1→6(Manα1→3)-Manβ1→4GlcNAc (Man5GlcNAc) and Manα1→6(Manα1→3)(Xy1β1→2)-Manβ1→4GlcNAcβ1→4(Fucα1→3)GlcNAc were shown to stimulate and delay ripening of mature green tomato fruit (Lycopersicon esculentum Mill. cv. Rutgers) at 1 and 10 ng (g fresh weight)−1, respectively (Priem and Gross 1992, Plant Physiol. 98: 399–401). Also, the occurrence and structure of 10 unconjugated N-glycans, including Man5GlcNAc, in tomato fruit were recently reported (Priem et al. 1993, Plant Physiol. 102: 445–458). In this work, we studied the potential interaction between Man5GlcNAc and several compounds by using a system that allowed pericarp discs to be kept up to 14 days after excision. Studies were performed to determine the effect of Man5GlcNAc, indole-3-acetic acid (IAA), concanavalin A and tomato lectin on ripening as defined by red coloration of the skin. Ripening in pericarp discs, unlike that in intact fruit, was unaffected by 1 ng (g fresh weight)−1 Man5GlcNAc. However, discs showed delayed ripening with 10 ng (g fresh weight)−1, and the delay of coloration was galactose dependent. Man5GlcNAc at 10 ng (g fresh weight)−1 inhibited the stimulation of coloration induced by 100 μ IAA in the presence of 40 μg (g fresh weight)−1 galactose. Man5GlcNAc lost biological activity in the presence of the two lectins. These results support the possible interaction of IAA and various oligosaccharides during plant growth and development, and for the first time suggest a physiological significance for tomato lectin. 相似文献
10.
《Journal of receptor and signal transduction research》2013,33(1-6):315-329
AbstractExcised dorsal skin of Anolis carolinensis was exposed to high intensity UV-irradiation in the presence of different photoreactive α-MSH derivatives. The resulting covalent binding of the hormone to its receptor induced irreversible pigment dispersion. The duration of the longlasting response depended on the type and length of irradiation; it was maximal after two 5 min irradiation phases with a light intensity of ~180 mW/cm2 and a spectrum from 310 to 550 nm, fresh hormone being added after the first phase. [Nα-(4-Azidophenyl-acetyl-serine1]-α-MSH (I), [2′-(2-nitro-4-azidophenylsulphenyl)-tryptophan9]-α-MSH (II) and [p-azidophenylalanine13]-α-MSH (III) all inserted into the receptor to about the same extent, as judged from the persistence of the longlasting signal. In contrast, [D-alanine1, p-azidophenylalanine2, norvaline4]-α-MSH (IV) and [Nα-(4-azidophenylacetyl)-serine1, leucine9]-α-MSH (V) gave much less insertion and [leucine9, p-azidophenylalanine13]-α-MSH (VI) hardly any insertion when applied in the same relative excess (5-fold the concentration inducing a maximal response). Covalent attachment of the cleavable photolabel [Nα-(4-azidophenyl)-1, 3′-dithio-propionyl-serine1]-α-MSH (VII) and subsequent washing of the skin in buffer containing 1% β-mercaptoethanol released the peptide from the receptor. Insertion of the C-terminal photolabel [p-azidophenylalanine13]-α-MSH was reduced by the weak antagonist H-Phe-Ala-Trp-Gly-Gly-Pro-Val-NH2. These experiments prove that hormone receptors can be covalently labelled in tissue with very limited light transparency. 相似文献
11.
《Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology》1989,994(3):285-288
At pH 8.0 and 25°C α1-proteinase inhibitor and α2-macroglobulin bind human pancreatic elastase with rate constants of 4.7·105 M−1·s−1 and 6.4·106 M−1·s−1, respectively. The corresponding delay times of elastase inhibition in plasma are 0.4 s and 0.2 s, respectively, indicating that both inhibitors may act as physiological antielastases. Elastin impairs the elastase inhibitory capacity of α1-proteinase inhibitor and α2-macroglobulin. In presence of human elastin, the former behaves like a slow-binding elastase inhibitor, with a rate constant of about 260 M−1·s−1. In contrast, α2-macroglobulin is a fast-binding inhibitor of elastin-bound elastase, but only one of its two sites is functioning in presence of elastin. 相似文献
12.
A rabbit lung preparation, perfused , was used to examine pulmonary metabolism of prostaglandin A1 (PGA1) and to compare the vasoconstrictor actions of PGA1, prostaglandin F2α (PGF2α) and angiotensin II. PGF2α caused significantly more, and angiotensin II significantly less, vasoconstriction than did an equimolar concentration of PGA1. Of three likely PGA1 metabolites only 15-keto-PGA1 had any significant vasoconstrictor action. Furosemide and aminophylline (10?3 M) reduced PGA1, PGF2α or angiotensin II-induced vasoconstruction. Diphloretin phosphate potentiated the vascular effect of angiotensin II. Furosemide (10?3 M) and DPP (9.5 × 10?6 M) significantly reduced pulmonary metabolism of PGA1 while aminophylline (10?3 M) had no effect on this process. Perfusion of the lungs with a hypoxic medium had no effect on PGA1 metabolism. 相似文献
13.
C V Rao 《Biochemical and biophysical research communications》1975,64(1):416-424
The cell membranes isolated from bovine corpora lutea bound 3H-prostaglandin (PG) F2α with high affinity and specificity. The specific binding of 3H-PGF2α was detectable at 10?10M added 3H-PGF2α and reached saturation at 10?7M to 10?6M. Unlabeled PGF2α, as low as 10?9M, inhibited the binding of 3H-PGF2α with complete inhibition occurring at 10?6M. The Scatchard analysis of equilibrium binding data revealed that the PGF2α receptors are heterogeneous: Kd1?5.1 × 10?9M, n?289 fmoles/mg protein; Kd2?1.8 × 10?8M, n?780 fmoles/mg protein. The relative affinities of various other PGs for binding to PGF2α receptors were (PGF2α?100%): PGF1α?17.5; PGE1?0.8; PGE2?22.4; PGA1?0.007; PGB1?0.01. The specificity and affinity of 3H-PGF2α binding is consistent with the possibility that this receptor interaction may reflect an initial event in the action of PGF2α as a luteolytic agent. 相似文献
14.
M Fukushima Y Suzuki Y Toira I Matsunaga K Ochi H Nagano 《Biochemical and biophysical research communications》1975,66(2):632-638
The metabolism of 1α-hydroxyvitamin D3 (1α-OH-D3) was studied in rat liver perfused with [3H]-1α-OH-D3. [3H]-1α-OH-D3 was converted very rapidly to a more polar metabolite, which was identified as 1α,25-dihydroxy-vitamin D3 [1α,25-(OH)2-D3] by co-chromatography with synthetic 1α,25-(OH)2-D3 as well as by gas chromatography-mass spectrometry. [3H]-1α,25-(OH)2-D3 appeared in the perfusate as early as 20 min after addition of [3H]-1α-OH-D3, and its level in the perfusate increased linearly for at least 120 min. These data strongly indicate that 1α-OH-D3 is metabolized to 1α,25-(OH)2-D3, which exerts biological effects on bone and intestine. 相似文献
15.
Gang Tang Yi Shen Pan Gao Shuang-Shuang Song Liang-Yi Si 《In vitro cellular & developmental biology. Animal》2018,54(3):250-256
Cardiac hypertrophy plays a major role in heart failure and is related to patient morbidity and mortality. Calcium overloading is a main risk for cardiac hypertrophy, and Na+/K+-ATPase (NKA) has been found that it could not only regulate intracellular Na+ levels but also control the intracellular Ca2+ ([Ca2+]i) level through Na+/Ca2+-exchanger (NCX). Recent studies have reported that klotho could affect [Ca2+]i level. In this study, we aimed at exploring the role of klotho in improving isoproterenol-induced hypertrophic response of H9C2 cells. The H9C2 cells were randomly divided into control and isoproterenol (ISO) (10 μM) groups. Klotho protein (10 μg/ml) or NKAα2 siRNA was used to determine the changes in isoproterenol-induced hypertrophic response. The alterations of [Ca2+]i level were measured by spectrofluorometry. Our results showed that H9C2 cells which were treated with isoproterenol presented a higher level of [Ca2+]i and hypertrophic gene expression at 24 and 48 h compared with the control group. Moreover, the expressions of NKAα1 and NKAα2 were both increased in control and ISO groups after treating with klotho protein; meanwhile, the NKA activity was increased and NCX activity was decreased after treatment. Consistently, the [Ca2+]i level and hypertrophic gene expression were decreased in ISO group after klotho protein treatment. However, these effects were both prevented by transfecting with NKAα2 siRNA. In conclusion, these findings demonstrated that klotho inhibits isoproterenol-induced hypertrophic response in H9C2 cells by activating NKA and inhibiting the reverse mode of NCX and this effect may be associated with the upregulation of NKAα2 expression. 相似文献
16.
Prostacyclin (PGI2) produced a biphasic response in canine isolated basilar arteries. In low doses (1 × 10?8M?1 × 10?7M) PGI2 caused a slight but consistent relaxation of resting muscle tone. In low concentrations (1 × 10?8M?1 × 10?6M) PGI2 antagonized muscle contractions caused by serotonin or prostaglandin (PG) F2α. This relaxant effect with low doses of PGI2 on the isolated cerebral artery contrasts with findings obtained with other PGs and supports the hypothesis that PGI2 is a mediator of vasodilatation. However, in 1 × 10?5M concentrations PGI2 contracted the arterial muscle and did not antagonize contractions induced by serotonin or PGF2α. 相似文献
17.
Catherine Grenot Claude-Yves Cuilleron 《Biochemical and biophysical research communications》1977,79(1):274-279
An electrophoretic elution procedure of antibodies retained on affinity columns is described. It afforded a 60% recovery of the binding activity of a high affinity (Ka ~ 1010 M?1) antiserum to 5α-dihydrotestosterone retained on antigen-linked Sepharose 4B affinity columns. These purified unbound antibodies, (Ka ~ 1010 M?1) when applied again on identical antigen-linked affinity columns, were all retained and totally recovered after a new electrophoretic elution. Comparable results were obtained by elution with 1M NH4OH.The residual 40% binding activity remaining on the antigen-linked Sepharose gel after electrophoretic elution was totally recovered by elution with an excess of 5α-dihydrotestosterone. It corresponded to antibodies of higher affinity (Ka ~ 1011 M?1). On the other hand the residual 40% fraction of antibodies resistant to NH4OH elution was denaturated. 相似文献
18.
《Journal of steroid biochemistry》1979,10(5-6):1507-1512
We studied the effect of cyclic AMP (cAMP) on steroidogenesis in a mouse Leydig cell tumor line (1–10). known to secrete exclusively progesterone (P) and 20α-dihydroprogesterone (20α-H2P). Radioimmunoassays that distinguish these two steroids were used. Total steroidogenesis was stimulated by cAMP in a dose-dependent manner over the range tested (10−6-10−3 M). Up to 2 × 10−5 M cAMP, progesterone constituted 11–13% of the secreted progestins: at higher concentrations of cAMP (10−4-10−3 M), the P/(P + 20α-H2P) ratio progressively increased (37% at 10−3 M), but the incremental progestin secretion consisted of 50% progesterone throughout this range. The change in progestin profile occurred within less than 45 min. 2-Mercapto-1-(β-4-pyridethyl)benzimidazole (MPB) reduced basal steroidogenesis, progesterone secretion being more severely affected than that of 20α-H2P. MPB inhibited cell growth and noncompetitively inhibited cAMP-dependent protein kinase activity in the cytosol of 1–10 cells. In a faster-growing variant of 1–10. higher concentrations of exogenous cAMP were required to exert similar effects on steroidogenesis. and MPB was less effective in suppressing cell growth. The possibility is discussed that cAMP may accelerate an active process of progesterone release, thus minimizing the intracellular exposure of the hormone to 20α-hydroxysteroid dehydrogenase, and that MPB antagonizes cAMP at a site influencing both steroid synthesis and release. 相似文献
19.
《Journal of steroid biochemistry》1984,20(4):999-1003
We have shown that the rate of release of PGF2α by monolayer cultures of epithelial cells from proliferative endometrium is markedly elevated by addition of estradiol to the medium. In cultures maintained in HAM F-10 medium containing charcoal stripped calf serum, estradiol (10−8M) increased the levels of PGF2α several fold during the second and third days in culture. Similar responses were obtained with estradiol at 10−10M concentration.When this system was used to compare the effects of estradiol and estriol at equal concentrations (10−8M), similar elevation (10–16-fold) of PGF2α levels were noted during 3 consecutive days in culture. When cultures of epithelial cells derived from secretory endometrium were used for these tests, estriol was as effective as than estradiol in elevating PGF2α levels in the medium.When the effects of estradiol and estriol were compared using fragments of secretory endometrium in organ culture, the increases in PGF2α levels noted in the medium were about equal (2- to 10-fold) for the two estrogens at the same concentration (10−9−10−8M).Exposure of the tissue to either estradiol or estriol for only 1 h resulted in increases in PGF2α output for the following 3 days.These results clearly show that estriol is as effective as estradiol in stimulating PGF2α output by human endometrial tissue. 相似文献
20.
Frances A. Kimball Kenneth T. Kirton Lillian J. Wyngarden 《Prostaglandins & other lipid mediators》1975,10(5):853-864
Myometrial low speed supernatant prepared from non-pregnant rhesus uteri was incubated with 3H-Prostaglandin (PG)E1 with or without addition of unlabelled prostaglandins. The uptake of 3H-PGE1 was inhibited in a dose dependent fashion by PGE2>PGE1>PGA1>PGF2α=PGA1>PGB1=PGB2≥PGD2. PGE1 metabolites inhibited 3H-PGE1 binding in the following order: 13,14-dihydro-PGE1>13,14-dihydro-15-keto-PGE1=15-keto-PGE1. The specific binding of 3H-PGE1 and 3H-PGF2α was similarly affected by the temperature and time of incubation. Equilibrium binding constants determined using rhesus uteri obtained during the luteal phase of the menstrual cycle indicate the presence of high affinity PGE1 binding sites with an average (n=3) apparent dissociation constant of 2.2 × 10−9M and a lower affinity PGE1 binding site with a Kd ≅ 1 × 10−8M. No high affinity — low capacity 3H-PGF2α sites could be demonstrated.Relative uterine stimulating potencies of some natural prostaglandins and prostaglandin analogs tested after acute intravenous administration in mid-pregnant rhesus monkeys corresponded with the PGE1 binding inhibition of the respective compound. The uterine stimulating potencies of the prostaglandin analogs tested were: (15S)-15-methyl-PGE2=16,16-dimethyl-PGE2>17-phenyl-18,19,20-trinor-PGE2>16 phenoxy-17,18,19,20-tetranor-PGF2α=PGE2=PGE1=(15S)-15-methyl-PGF2α>PGF2α. 相似文献