Abstract:
:Both gonadotropin-releasing hormone (GnRH) and prostaglandin F2 alpha (PGF2 alpha) can inhibit cAMP and progesterone production in the corpus luteum; however, their mechanism of action is not known. GnRH or PGF2 alpha causes a rapid and marked increase of labelling of phosphatidylinositol (PI) and phosphatidic acid (PA) in rat luteal cells in culture. The incorporation of radioactivity is increased as early as 2 and 5 min into PA and PI, respectively. The labelling of the other phospholipids is not affected. GnRH and PGF2 alpha exert their stimulatory effects on PA-PI turnover at a mean effective dose value of ca. 15 and 100 nM, respectively. Their effects appeared to be additive when both agents were present in the same incubations. Interestingly, addition of the calcium ionophore A23187 also causes a dramatic increase of PA-PI turnover in luteal cells. By contrast, human chorionic gonadotropin and isoproterenol, agents that stimulate cAMP and progesterone production in luteal cells, as well as PGE2 (1 microM), all fail to alter phospholipid labelling; dibutyryl or 8-bromo-cAMP (2-5 mM) actually attentuates the GnRH or PGF2 alpha effect on PI and PA. A very similar PA-PI response to GnRH and PGF2 alpha has also been observed using rat granulosa cells in culture. It seems that following their binding to membrane receptors, GnRH and PGF2 alpha may share a common mechanism in the ovarian cell, possibly involving the stimulation of PA-PI metabolism.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Leung PCdoi
10.1139/y85-046subject
Has Abstractpub_date
1985-03-01 00:00:00pages
249-56issue
3eissn
0008-4212issn
1205-7541journal_volume
63pub_type
杂志文章,评审abstract::A variety of porphyrinogenic xenobiotics cause mechanism-based inactivation of a number of rat hepatic cytochrome P450 isozymes. As a result, a mixture of four N-alkylprotoporphyin IX (N-alkylPP) regioisomers, with ferrochelatase-inhibitory properties, are formed. This study was designed to determine whether all four ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1996-08-01 00:00:00
abstract::Urinary output of Na+ and K+, and volume of urine have been studied in conscious, unrestrained, water-loaded male rats following the intraseptal injection of catecholamines. Natriuresis and kaliuresis increased after injecting noradrenaline (NA), the intensity being dose related. The dose-response curve suggests that ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y76-034
更新日期:1976-06-01 00:00:00
abstract::Neural and paracrine agents, such as dopamine, epinephrine, and histamine, affect intestinal epithelial function, but it is unclear if these agents act on receptors directly at the enterocyte level. The cellular localization and villus-crypt distribution of adrenergic, dopamine, and histamine receptors within the inte...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y05-024
更新日期:2005-05-01 00:00:00
abstract::This study investigated the effects of melatonin treatment on adrenal catecholamine content, synthesis, uptake, and vesicular transport induced by the chronic unpredictable mild stress (CUMS) model of depression in rats. This entailed quantifying the norepinephrine, epinephrine, mRNA, and protein levels of tyrosine hy...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2018-0612
更新日期:2019-07-01 00:00:00
abstract::Mechanisms leading to ifosfamide (IF)-induced renal damage have not been fully elucidated. Recent work suggests that localized renal tubular metabolism of IF and the production of the nephrotoxic chloroacetaldehyde may lead to nephrotoxicity. Presently no pharmacological method to reduce IF nephrotoxicity has been ide...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y05-036
更新日期:2005-06-01 00:00:00
abstract::The pulmonary vascular resistance in a peripheral portion of the pulmonary vascular bed can be determined with a catheter wedged in a peripheral branch of the pulmonary artery, from the pressure increase induced by infusion of mixed venous blood at known flow rates. The volume of the wedged vascular bed can be estimat...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1997-01-01 00:00:00
abstract::The causes of reduced levels of omega-3 and omega-6 highly unsaturated fatty acids ("HUFA deficiency") in heart failure remain unresolved. HUFA profiles were examined in the serum of 331 patients with failing versus nonfailing heart disease. Arachidonic acid was positively correlated (P < 0.001) with eicosapentaenoic ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 临床试验,杂志文章
doi:10.1139/y11-101
更新日期:2012-01-01 00:00:00
abstract::This study has investigated the oral activity, following intragastric administration, of three potent and long-acting peptide-based bradykinin antagonists, HOE-140, B9430, and CP-0597, in the anesthetized rat, using bradykinin-induced hypotension. Two of the three bradykinin antagonists, B9430 and HOE-140, but not CP-...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1997-06-01 00:00:00
abstract::Small, sinusoidal length changes were superimposed on isometric contractions of fast- and slow-twitch mouse muscles, which were stimulated maximally via their nerves. Stiffness increased with increasing frequency of sinusoidal stimulation, but the relative time course of force and stiffness changes during twitch, teta...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y86-209
更新日期:1986-09-01 00:00:00
abstract::The distribution of atrial natriuretic factor (ANF) binding sites in Wistar rat tissues, as well as tissues from other species was studied. Using autoradiography of slide mounted tissue sections incubated with 125I-labelled ANF, high densities of binding sites were found in the renal glomeruli and papilla, aortic smoo...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-226
更新日期:1985-11-01 00:00:00
abstract::The aim of the present investigation was to elucidate the pharmacological mechanism by which U44069, a stable PGH2 analogue, contracts the rat aorta. The results obtained demonstrate that while the contractile effect of potassium chloride is obliterated by removal of extracellular calcium, a substantial proportion of ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y82-103
更新日期:1982-05-01 00:00:00
abstract::Cyclic AMP formation from ATP was stimulated by unpurified and partially purified soluble hepatic guanylate cyclase in the presence of nitric oxide (NO) or compounds containing a nitroso moiety such as nitroprusside, N-methyl-N-nitro-N-nitrosoguanidine (MNNG), nitrosyl ferroheme, and S-nitrosothiols. Cyclic AMP format...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y80-219
更新日期:1980-12-01 00:00:00
abstract::The objective of this study was to explore the action of angiotensin II (AII) on cardiac contractility and cyclic AMP (cAMP) generation by forskolin and isoproterenol in the hypertrophic myocardium of the salt-sensitive Dahl rat. Inbred Dahl S and Dahl R rats that had been on a diet supplemented with 6% NaCl were stud...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y94-086
更新日期:1994-06-01 00:00:00
abstract::The contractile recoverability of isolated portal veins made hypodynamic by removal of glucose from the perfusion medium by diverse exogenous substrates was studied. It was found that glucose, mannose, pyruvate, lactate, acetate, and butyrate readily restored contraction. The effects of anoxia and metabolic inhibitors...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y80-115
更新日期:1980-06-01 00:00:00
abstract::The rate of appearance of unlabelled glucose was calculated from changes in plasma glucose specific radioactivity after a single intravenous injection of labelled glucose and compared with the actual constant infusion rate of unlabelled glucose into an anaesthetized dog with all sources of endogenous glucose productio...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y79-191
更新日期:1979-11-01 00:00:00
abstract::The effects of beta-cyclodextrin (betaCD) inclusion complexation on the ability of violacein to prevent gastric ulceration in mice were studied. Violacein-betaCD inclusion complexes were prepared in 1:1 and 1:2 molar ratios and analysed by differential scanning calorimetry and powder X-ray diffractometry. Violacein pr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y03-033
更新日期:2003-04-01 00:00:00
abstract::Several studies suggest that heat stress affects placental functions including uteroplacental circulation, subsequently leading to pregnancy failure and birth weight reduction. To clarify the involvement of endothelin and placental prostaglandin (PG) systems in the uteroplacental circulation during heat stress, we exa...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y04-011
更新日期:2004-04-01 00:00:00
abstract::Temporary block of glycolysis by 2-deoxy-D-glucose (2-DG) reversibly suppresses synaptic transmission in the CA1 region of hippocampal slices. Recovery of responses is followed by a sustained potentiation of field excitatory postsynaptic potentials (EPSPs) (2-DG-LTP). To investigate the mechanisms involved in this typ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1997-05-01 00:00:00
abstract::Several experimental data document an activation of the mitogen-activated protein kinases Erk1 and Erk2 by bradykinin (BK), an agonist of the kinin B2 receptor (B2R). In contrast, other reports showed an inhibitory modulation of mitogenesis by BK. Therefore, we explored in the isolated glomeruli the effect of B2R acti...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y02-033
更新日期:2002-04-01 00:00:00
abstract::Acetylcholine (ACh) is an important regulator of intestinal epithelial ion transport via muscarinic or nicotinic ACh receptors. Previous studies emphasize the role of the M3 muscarinic receptor subtype in mediating the effects of cholinergic agonists on intestinal ion transport. With the prevalence of mouse models to ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y06-068
更新日期:2006-11-01 00:00:00
abstract::In the mesenteric circulation of the rat a myogenic autoregulatory system operates at 0.1-0.15 Hz. Negative admittance phase in the region above 0.2 Hz suggested operation of an arterial baroreflex. The present study was designed to test this interpretation and to identify the neurotransmitter involved. In rats anesth...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-78-1-54
更新日期:2000-01-01 00:00:00
abstract::Although mitochondrial transcription factor A (TFAM) is a protective component of mitochondrial DNA and a regulator of calcium and reactive oxygen species (ROS) production, the mechanism remains unclear. In heart failure, TFAM is significantly decreased and cardiomyocyte instability ensues. TFAM inhibits nuclear facto...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2016-0718
更新日期:2018-02-01 00:00:00
abstract::The relationship between the postsynaptic alpha 1-adrenoceptor reserve and the sensitivity of vasoconstriction induced by alpha-adrenoceptor agonists to the dihydropyridine Ca2+ entry blocker nifedipine was investigated in isolated muscle strips of dog mesenteric artery (DMA) and saphenous vein (DSV). The amplitudes o...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y90-203
更新日期:1990-10-01 00:00:00
abstract::Local microinjections of harmaline evoked sustained rhythmic activity in the inferior olive of decerebrate cats. Harmaline appears to exert its action within restricted areas of the inferior olivary complex: the caudal halves of the dorsal and medial accessory nuclei. Since the highly synchronized activity generated b...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y75-116
更新日期:1975-10-01 00:00:00
abstract::The present research was to assess the relationship between ABCB1 (G2677T/A, C3435T) polymorphisms and lipid homeostasis as well as risk of liver injury induced by atorvastatin in in-patients from China. The lipid levels (total cholesterol, high-density lipoprotein, triglycerides) as well as metabolic enzymes of hepar...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2019-0339
更新日期:2020-01-01 00:00:00
abstract::The effects of a number of peptides which are found in the gastrointestinal tract have been ascertained on the direct current recorded dorsal and ventral root responses of the isolated hemisected toad spinal cord. Motilin, substance P, bombesin, neurotensin, and thyrotropin releasing hormone had potent depolarizing ac...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y79-136
更新日期:1979-08-01 00:00:00
abstract::Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y04-034
更新日期:2004-05-01 00:00:00
abstract::Metabolic syndrome (MS) is a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes. MS is associated with obesity, increased blood pressure, hyperlipidemia, and hyperglycemia. This study was designed to investigate the pharmacological profile of phentolamine, a nonse...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y2012-063
更新日期:2012-08-01 00:00:00
abstract::The effect of isoproterenol on mean right and left atrial pressures (RAP, LAP) and dimensions (RAD, LAD), and plasma immunoreactive atrial natriuretic factor (IR-ANF) was investigated in anesthetized rabbits. Infusion of isoproterenol (10 micrograms.kg-1.min-1 for 10 min) significantly increased plasma IR-ANF and hear...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y91-069
更新日期:1991-04-01 00:00:00
abstract::In sepsis, systemic inflammatory response syndrome (SIRS), and multiorgan dysfunction syndrome (MODS), a severe prognostically relevant cardiac autonomic dysfunction exists, as manifested by a strong attenuation of sympathetically and vagally mediated heart rate variability (HRV). The mechanisms underlying this attenu...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/Y09-012
更新日期:2009-04-01 00:00:00