Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A concomitant increase in the activity of LH-senstive adenylate cyclase and in the number of LH/hCG binding sites was induced in ovaries of immature rats upon administration of pregnant mare serum gonadotropin (PMSG), a hormone preparation known to have predominantly follicle stimulation (FSH-like) activity. When an optimal dose of PMSG (15 i.u./rat) was administered to 25-day-old rats, specific activity of LH-dependent adenylate cyclase and the number of binding sites for LH/hCG per mg protein remained unchanged during the first 24h, but 48h after injection a 2-to 4-fold increase in both parameters was observed. By contrast, there was no change in basal adenylate cyclase activity or in the response of the enzyme to the stimulatory action of guanosine-5'-(beta gamma-imino) triphosphate (Gpp (NH)p), GTP, or NaF. Specific activity of succinate cytochrome c reductase, glucose-6-phosphatase and 5'-nucleotidase were found to be unaffected by the hormonal pretreatment, although total protein determined in these homogenates increased 3-fold in the course of this treatment. It is inferred that during follicular maturation, FSH enhances the responsiveness of ovarian adenylate cyclase to LH by stimulating the insertion of LH/hCG-receptors into the cell membrane.
 ...
PMID:Synchronous generation of ovarian hCG binding sites and LH-sensitive adenylate cyclase in immature rats following treatment with pregnant mare serum gonadotropin. 19 42

More than half of the extranuclear receptor content of resting cells is associated with cytoplasmic structures. Subfractionation of microsomes reveals a preponderance of "basic" (low electrophoretic mobility) receptor in rough endoplasmic reticulum. Surfynol-dithiothreitol extracts of smooth membranes are rich in "acidic" (high electrophoretic mobility) receptor. Trypsin increases the yields up to seven-fold, and this increase is correlated (r = 0.993) with the acidic receptor content and 5'-nucleotidase activity of these microsomal preparations. Acidic microsomal "cytosolic" and nuclear receptor can be degraded to the "basic" variety of streptomyces hyaluronidase. All forms give rise to a tryptic fragment with unchanged affinity for oestradiol and dimerization ability. Basic receptor isolated after enzymatic conversion of acidic receptor is microheterogenous on isoelectric focusing, but gives rise to only one precipitation arc versus the IgG fraction of a polyclonal antiserum. The precipitation arc can be recharged with labelled oestradiol and autoradiographed. Non-immune IgG's from (unspecific) soluble complexes with oestrogen receptors, but not with their tryptic fragments. The polyclonal antioestrogen receptor IgG fraction precipitates the oestradiol-tagged tryptic receptor fragment from all subcellular sources of all homologous (porcine) and heterologous (human, ovine, bovine, goat, rabbit, guinea pig, rat) target tissues tested. Organ specificity can therefore be excluded and a high degree of phylogenetic conservation of the oestrogen receptor's protein moiety is implied. The presence, in the immune IgG fraction, of steroid releasing antibodies, which apparently distort the binding site, should spur the search for monoclonal antibodies with similar properties.
 ...
PMID:Subcellular distribution, properties and interrelationship of oestrogen receptors in endometrium and other target tissues. 663 34

The effect of fasting on 5'-nucleotidase activity was assessed in microsomes and purified plasma membranes from rat liver. The microsomal 5'-nucleotidase activity (mean value: 0.062 mumol/min/mg protein at 37 degrees C in the fed rat) is increased about twice in the fasted rat (mean values: 0.11, 0.125 and 0.11 mumol/min/mg protein after 24, 48 and 72 hours of fasting, respectively). This result was further confirmed after separation of plasma membranes from the bulk of microsomial membranes by sucrose gradient centrifugation. The results are discussed with respect to the phosphatidylinositol glycan-mediated anchoring of the ectoenzyme to the cell membrane and to the putative biological effect of extracellular adenosine on the liver metabolism.
 ...
PMID:[Increase of 5'-nucleotidase activity in liver plasma membranes during fasting in the rat]. 783 1