The synthesis of α-amylase by rough and in vitro reconstituted rough endoplasmic reticulum derived from rat parotid gland

1976 ◽  
Vol 2 (6) ◽  
pp. 455-463
Author(s):  
Bernard Cwikel ◽  
Rachel Avner ◽  
Henryk H. Czosnek ◽  
Abraham A. Hochberg ◽  
Nathan de Groot
Keyword(s):  
Endoplasmic Reticulum ◽  
Parotid Gland ◽  
Rough Endoplasmic Reticulum ◽  
Rat Parotid Gland ◽  
Rat Parotid

scholarly journals Parotid microsomal Ca2+ transport. Subcellular localization and characterization

1982 ◽  
Vol 208 (3) ◽  
pp. 789-794 ◽  
Author(s):  
P Kanagasuntheram ◽  
T S Teo
Keyword(s):  
Endoplasmic Reticulum ◽  
Parotid Gland ◽  
Subcellular Localization ◽  
Microsomal Fraction ◽  
Narrow Range ◽  
Differential Centrifugation ◽  
Linear Rate ◽  
Rat Parotid Gland ◽  
Rat Parotid ◽  
Nadph Cytochrome C Reductase

Rat parotid gland homogenates were fractionated into mitochondrial, heavy microsomal and light microsomal fractions by differential centrifugation. ATP-dependent 45Ca2+ uptake by the subcellular fractions paralleled the distribution of NADPH-cytochrome c reductase, an enzyme associated with the endoplasmic reticulum. The highest rate of Ca2+ uptake was found in the heavy microsomal fraction. Ca2+ uptake by this fraction was dependent on the presence of ATP and was sustained at a linear rate by 5 mM-oxalate. Inhibitors of mitochondrial Ca2+ transport had no effect on the rate of Ca2+ uptake. Na+ and K+ stimulated Ca2+ uptake. At optimal concentrations. Na+ stimulated Ca2+ uptake by 120% and K+ stimulated Ca2+ uptake by 260%. Decreasing the pH from 7.4 to 6.8 had little effect on Ca2+ uptake. The Km for Ca2+ uptake was 3.7 microM free Ca2+ and 0.19 mM-ATP. Vanadate inhibited Ca2+ uptake; 60 microM-vanadate inhibited the rate of Ca2+ accumulation by 50%. It is concluded that the ATP-dependent Ca2+ transport system is located on the endoplasmic reticulum and may play a role in maintaining intracellular levels of free Ca2+ within a narrow range of concentration.

Kinetic analysis of rat parotid gland muscarinic receptors in vivo: comparison with brain and heart

1993 ◽  
Vol 264 (3) ◽  
pp. G541-G552
Author(s):  
Y. Hiramatsu ◽  
R. Kawai ◽  
R. C. Reba ◽  
T. R. Simon ◽  
B. J. Baum ◽  
...  
Keyword(s):  
Parotid Gland ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Muscarinic Acetylcholine Receptor ◽  
Binding Potential ◽  
Specific Binding Sites ◽  
Rat Parotid Gland ◽  
Rat Parotid

(RR)- and (SS)-quinuclidinyl iodobenzilate enantiomers [(RR)- and (SS)-IQNB, active and inert, respectively] have been synthesized for quantitative evaluation of muscarinic acetylcholine receptor (mAChR) binding. Pharmacokinetic approaches have not been used previously to assess in vivo IQNB binding in nonexcitable tissues. We have applied this method to examine mAChRs in rat parotid gland in comparison to those in brain and heart. Short-term infusion studies in vivo showed that the "instantaneous" reversible binding of (RR)- and (SS)-IQNB was high in the parotid (greater nonspecific binding potential), intermediate in the heart, and lowest in cortex and cerebellum. Long-term bolus injection experiments showed that the parotid gland mAChRs possessed a binding potential for receptor specific sites (380), which was intermediate between that of parietal cortex (930) and cerebellum (10) and greater than that of heart (165). In vitro binding to plasma membranes was generally consistent with the in vivo findings. In aggregate, these studies show that mAChRs can be evaluated in vivo in a nonexcitable tissue with the use of stereospecific ligands and a pharmacokinetic approach. The data suggest that IQNB, a mAChR antagonist, can identify characteristics of specific binding sites, which may reflect tissue differences.

scholarly journals Calcium-dependent inhibition of protein synthesis in rat parotid gland

1978 ◽  
Vol 176 (1) ◽  
pp. 23-29 ◽  
Author(s):  
P Kanagasuntheram ◽  
S C Lim
Keyword(s):  
Protein Synthesis ◽  
Parotid Gland ◽  
Ionophore A23187 ◽  
Phenylalanine Concentration ◽  
Calcium Dependent ◽  
Rat Parotid Gland ◽  
Inhibition Of Protein Synthesis ◽  
Dependent Inhibition ◽  
Rat Parotid

1. Protein synthesis in the rat parotid gland in vitro was studied by measuring the incorporation of [3H]phenylalanine into trichloroacetic acid-insoluble proteins. In the unstimulated gland, the rate of incorporation was dependent on the phenylalanine concentration in the medium and proceeded linearly for up to 3h. 2. Adrenaline, carbamoylcholine, phenylephrine and ionophore A23187 inhibited the incorporation of [3H]phenylalanine into acid-insoluble protein; isoprenaline, dibutyryl cyclic AMP and 8-bromo-cyclic GMP were inactive. 3. Inhibition by adrenaline and carbamoylcholine but not by ionophore A23187 required extracellular Ca2+. 4. Both adrenaline and carbamoylcholine increased the magnitude of the acid-soluble [3H]phenylalanine pool at 10 micrometer extracellular phenylalanine, but had no effect if the phenylalanine concentration was increased to 200 micrometer. 5. There was no correlation between cellular ATP content and the observed inhibition of protein synthesis. 6. Our results suggest that both alpha-adrenergic and cholinergic receptors may play a role in the regulation of protein synthesis in the rat parotid gland, and that their effects are mediated by a rise in intracellular free Ca2+.

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