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1.
A Dutour P Giraud C Kowalski L Ouafik P Salers V Strbak C Oliver 《Biochemical and biophysical research communications》1987,146(1):354-360
The rapid changes in TRH levels in the rat pancreas during the neonatal period make this organ an interesting model for the study of the regulation of TRH biosynthesis. Pancreatic RNAs were isolated by the guanidinium thiocyanate method and layered onto CsCl cushion. Northern blot preparations were hybridized with 32P labeled TRH cDNA probe. Pancreatic TRH mRNA was first detected in 19-day old fetuses and reached the highest level on day 0, then decreased, being barely detectable 14 days after birth. The neonatal injection of streptozotocin induced a dramatic drop of TRH mRNA levels 24 hours later. This result suggests that the peculiar evolution of TRH level in pancreas is partly due to the evolution of the expression of the TRH gene. 相似文献
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C Julian M C Tordo G Macquart-Moulin J P Moatti F Giraud S Aymé 《Social biology》1989,36(3-4):240-247
A study of factors influencing genetic counseling attendance rate has been conducted in the Bouches-du-Rh?ne area, in the south of France. In this area, a birth defects monitoring system (Eurocat n. 22) annually covers 23,000 births. All the genetic services are delivered by only one genetic center located in Marseilles, and the data collected are computerized. The comparison of these two data bases gives an opportunity to estimate the rate of genetic counseling attendance after the occurrence of an affected stillbirth or live birth. Among the parents of 358 infants born in 1983-84 in this area with a pathology requiring genetic counseling, 226 (63 per cent) attended the Genetic Center within the first year after birth. The rate of attendance is statistically higher (p less than 0.01) for the parents who had a stillbirth (78 per cent) than for those who had a live birth (57 per cent). It is also higher (p less than 0.01) for the Marseilles maternities group (68 per cent) than for the group outside Marseilles (50 per cent). The referral delays are also analyzed according to malformation etiology and to viability of the child by the eighth day of life. Besides evaluating a particular genetic center's effectiveness in diffusing information to the public concerned, this work shows that couples' request is strongly dependent on a psychological need. 相似文献
5.
In agreement with previous data, membrane protein phosphorylation was found to be altered in intact sickle cells (SS) relative to intact normal erythrocytes (AA). Similar changes were observed in their isolated membranes. The involvement of protein kinase C (PKC) in this process was investigated. The membrane PKC content in SS cells, measured by [3H]phorbol ester binding, was about 6-times higher than in AA cells. In addition, the activity of the enzyme, measured by histone phosphorylation was also found to be increased in SS cell membranes but decreased in their cytosol compared to the activity in AA cell membranes and cytosol. The increase in membrane PKC activity was observed mostly in the light fraction of SS cells, fractionated by density gradient, whereas the decrease in cytosolic activity was only observed in the dense fraction. PKC activity, measured in cells from the blood of reticulocyte-rich patients, exhibited an increase in both membranes and cytosol, thus explaining some of the effects observed in the SS cell light fraction, which is enriched in reticulocytes. The increase in PKC activity in the membranes of SS cells is partly explained by their young age but the loss of PKC activity in their cytosol, particularly in that of the dense fraction, seems to be specific to SS erythrocytes. The relative decrease in membrane PKC activity between the dense and the light fractions of SS cells might be related to oxidative inactivation of the enzyme. 相似文献
6.
Paul Salers L'Houcine Ouafik Pierre Giraud Anne Dutour Jean-Yves Maltese Charles Oliver 《Molecular and cellular biochemistry》1991,106(1):15-24
Thyrotropin-R eleasing hormone (TRH)-degrading pyroglutamyl peptidase I(PGP I) and prolyl endopeptidase (PE) activities have been demonstrated in rat insulinoma RINm 5F cell line. These two enzymes catalyze the conversion of TRH to Histydyl-Proline-Diketopiperazine and to acid TRH respectively.After cell fractionation, we found all the PGP I and PE activities in the cytosolic fraction. The membranebound PGP II activity is not detectable in the RINm 5F cells. Further investigations on these two cytosolic enzymes show that pyroglutamyl- and proline-containing peptides are inhibitors of each TRH-degrading enzyme.Gelfiltration chromatography on Sephadex G100 shows that PGP I and PE activity have an apparent molecular mass of about 18 kDa and 57 kDa, respectively. Kinetic analysis with TRH as substrate, gives a Km of 44 µM and 235 µM, and a Vmax of 1.49 and 8.80 pmoUmin/µg protein for PGP I and PE, respectively. Immunoreactive TRH, His-Pro-Diketopiperazine and acid TRH levels in the cell line extracts are 2.2 ± 0.9, 22.5 ± 11.1 and 28.7 ± 14.6pg/106 cells, respectively. When cells have been incubated for 2 to 72 hours with a P. E. inhibitor (Z-Gly-Pro-CHN2) at 5 × 10–7M, both cell PGP I and PE activities are inhibited. No change in the cellular content of immunoreactive TRH, His-Pro-Diketopiperazine and acid TRH have been observed in treated cells.These data suggest that TRH is not degraded by cytosolic, unspecific PGP I and PE enzymes in RINm 5F. The finding that these cells contain 10 and 13 times more His-Pro-Diketopiperazine and acid TRH than TRH may be an indirect evidence for the existence of another precursor than TRH for these two peptides or of the possibility that TRH can be degraded by other peptidases.Abbreviations TRH
Thyrotropin-Releasing Hormone or Thyroliberin
- His-Pro-DKP
Histidyl-ProlineDiketopiperazine
- TRH-OH
acid TRH or deamidated TRH
- LH-RH
Luteinizing Hormone-Releasing Hormone
- Z-Gly-Pro-CHN2
N-benzyloxycarboxyl-Gly-Pro-diazomethylketone
- PGP
Pyroglutamyl Peptidase, PGP I (EC 3.4.19.3) and PGP II (EC 3.4.19.-)
- PE
Prolyl Endopeptidase or post-proline cleaving enzyme (EC 3.4.21.26) 相似文献
7.
Interaction of Opiates with Opioid Binding Sites in the Bovine Adrenal Medulla: I. Interaction with δ and μ Sites 总被引:2,自引:1,他引:1
E. Castanas N. Bourhim P. Giraud F. Boudouresque P. Cantau C. Oliver 《Journal of neurochemistry》1985,45(3):677-687
In the present study we examined the interaction of opiates with the delta and mu opioid binding sites in the bovine adrenal medulla. [3H][D-Ala2, D-Leu5]-enkephalin ( [3H]DADLE) in the presence of saturating concentrations of morphiceptin was used to analyze delta site interactions, whereas either [3H]DADLE in the presence of saturation concentrations of [D-Ser2, Leu5]-enkephalin-Thr6 (DSLET) or [3H][D-Ala2, Me-Phe4, Gly5-ol]-enkephalin ( [3H]DAGO) was used for the determination of mu sites. Both binding sites were found to interact stereoselectively with opiates. The binding was affected differentially by proteolytic enzymes (trypsin, alpha-chymotrypsin, pepsin), N-ethylmaleimide, and A2-phospholipase. Kinetic and equilibrium binding studies revealed that in each case radiolabeled opiates interact with one class of binding sites, following simple second-order bimolecular kinetics. Competition for binding by opiates and opioid peptides confirmed the delta and mu selectivity of these sites. Monovalent (Na+, Li+, K+) and divalent (Mg2+, Mn2+, Ca2+) ions interacted differentially with these two binding sites: In general, monovalent cations affected preferentially the apparent number of binding sites, whereas divalent ions modified the equilibrium dissociation constant. Furthermore, positive or negative cooperativity and an apparent heterogeneity of binding sites were detected under some ionic conditions. 相似文献
8.
Compartmentalization of Ca2+ in sickle cells 总被引:2,自引:0,他引:2
Control (AA) and sickle cell anemia (SS) erythrocytes were loaded with Ca-chelator (Quin2 or Benz2) to increase the cellular exchangeable Ca2+ pool and to measure the Ca2+ exchange fluxes and the cytosolic ionized Ca2+ ([Ca]i) (Lew et al., 1982, Nature, 298, 478). The chelator incorporation induced a decrease in the ATP content which was smaller in SS than in AA cells and partially reversible upon reincubation in a chelator-free medium. The amount of trapped chelator was determined by two methods: 45Ca binding to the chelator in Ca-ionophore treated cells in Ca-EGTA buffers and [3H]Quin2 incorporation. A slight over-estimation of the chelator content was found with the second method but incorporation was the same in both types of cells. The kinetics of 45Ca equilibration and 45Ca release were used to measure Ca2+ fluxes and [Ca]i in oxygenated chelator-loaded cells. SS cells, as compared to AA cells, exhibited a moderate increase in Ca2+ fluxes (30-75%) but [Ca]i remained in the same range (about 20 nM). Thus the excess of Ca2+ found in SS cells is not available for the Ca2+ pump or the K+ channel a conclusion in agreement with that of Bookchin et al. (1984, Cell Calcium, 5, 277). Analysis of the 45Ca kinetics showed that in AA cells, exchangeable Ca2+ behaved as one compartment. In SS cells, the existence of a second slowly-exchangeable Ca2+ compartment was demonstrated. This latter (3-5 mumol/l cells) was independent of the concentration of the chelator and thus could represent exchangeable Ca2+ enclosed within the intracellular inside-out vesicles recently observed in SS cells (Williamson et al., 1984, J. Cell. Biol., 99, 430a). Alternatively, these two kinetic pools could reflect heterogeneity of the SS cell population. 相似文献
9.
C Carydakis N Bourhim P Giraud P Cantau C Oliver E Castanas 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1986,302(11):419-422
This note reports the interaction of three currently used tricyclic antidepressant drugs (clomipramine, imipramine and amitriptyline) with delta, mu and kappa opioid binding sites in the bovine adrenal medulla. Clomipramine was the only drug interacting with delta and mu sites. On the contrary, all three drugs showed a significant interactions with subtypes of the kappa binding site. Clomipramine was the most active on the kappa 2 and kappa 3 subtypes while amitriptyline showed the highest interaction with the kappa 1 subtype. On the contrary the tricyclic cyproheptadine did not present any interaction with opioid binding sites in our system. This interaction between tricyclic antidepressants and opioid binding sites might be the origin of their analgesic action. 相似文献
10.
N Alloisio F Giraud Y Boutalbi B Chailley J Delaunay 《Biochimica et biophysica acta》1983,727(2):255-265