scholarly journals Turnover of metallothioneins in rat liver

1978 ◽  
Vol 174 (1) ◽  
pp. 327-338 ◽  
Author(s):  
R D Andersen ◽  
W P Winter ◽  
J J Maher ◽  
I A Bernstein
Keyword(s):  
Radioactive Isotope ◽  
Single Injection ◽  
Thiol Group ◽  
Control Value ◽  
Metal Treatment ◽  
Wet Weight ◽  
Cdcl2 Treatment ◽  
Stimulation Of ◽  
Rate Of Accumulation

Two electrophoretically distinguishable metallothioneins were isolated from the livers of Cd2+-treated rats and had thiol group/metal ratios of 3:1, a total metal content, in each of these proteins, of 3.6 atoms of Cd2+ + 2.4 atoms of Zn2+/molecule and 4.2 atoms of Cd2+ + 2.8 atoms of Zn2+/molecule and respective apoprotein mol.wts. of 5844 and 6251. Studies with 1 h pulse labels of [3H]cysteine, given after a single injection of ZnCl2 or CdCl2, showed that these metals stimulated radioactive isotope incorporation into the metallothioneins over the control value by 10- and 15-fold respectively. This stimulation was maximal at 4 h after a single CdCl2 injection and decreased to control values by 16 h, suggesting that either a translational event is responding to free intracellular Cd2+ or a short-lived mRNA is being produced or stabilized in response to the metal treatment. In rats chronically exposed to CdCl2, the metallothioneins increased to 0.2% of the liver wet weight from a control value of 2–4 mumol/kg of liver, with a maximum rate of accumulation of 2–3 mumol/h per kg of liver. The turnover of these proteins in control animals was 0.3–0.6 mumoles/h per kg of liver, measured by the rate of disappearance of 203Hg2+, which binds irreversibly to the metallothioneins. Pretreatment with CdCl2 completely stopped the rapid 203Hg turnover observed in untreated animals. Unlike CdCl2, treatment with ZnCl2 increased the concentration of metallothioneins to a new steady-state pool, 11 mumole/kg of liver, after 10 h. The increase in the zinc-thionein pool by exposure to ZnCl2 in vivo was determined to be primarily due to a stimulation of metallothionein biosynthesis.

AUGMENTATION BY CHLORMADINONE OF THE UTERINE WEIGHT RESPONSE TO HUMAN CHORIONIC GONADOTROPHIN IN INTACT IMMATURE RATS

1965 ◽  
Vol 33 (3) ◽  
pp. 447-454
Author(s):  
M. J. K. HARPER
Keyword(s):  
Single Injection ◽  
Direct Action ◽  
Follicular Development ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Uterine Weight ◽  
Control Value ◽  
Orally Active ◽  
Stimulation Of

SUMMARY Administration of chlormadinone, an orally active progestational agent without significant oestrogenic activity, to intact immature female rats did not affect either ovarian or uterine weight significantly compared with controls. A single injection of human chorionic gonadotrophin (HCG) caused a 73 % increase in uterine weight in 24 hr. over the control value. This dose significantly increased ovarian weight and although it caused some stimulation of follicular development, ovulation during this time did not occur. When animals were treated with chlormadinone for 8 days, and received HCG on the 8th day, uterine weight was 170% greater than in the controls and 56% greater than with HCG alone. The uterine weight produced was similar to that found in animals treated with mestranol, a potent oestrogen, and HCG. In ovariectomized animals HCG did not affect uterine weight, while the small increase produced by chlormadinone was unaltered when HCG also was given. Mechanisms are discussed by which this augmentation of the uterine response to HCG might be produced. It seems most likely that chlormadinone administration causes storage of endogenous gonadotrophin in the pituitary, and that the exogenous gonadotrophin acts as the 'trigger' for the release of stored hormone, probably by a direct action on the hypothalamus.

scholarly journals THE EFFECTS OF SECRETAGOGUES ON THE INCORPORATION OF [2-3H]MYOINOSITOL INTO LIPID IN CYTOLOGICAL FRACTIONS IN THE PANCREAS OF THE GUINEA PIG IN VIVO

1973 ◽  
Vol 56 (3) ◽  
pp. 736-745 ◽  
Author(s):  
Dorothy Gerber ◽  
Margaret Davies ◽  
Lowell E. Hokin
Keyword(s):  
Endoplasmic Reticulum ◽  
Single Injection ◽  
Enzyme Secretion ◽  
Amylase Level ◽  
Membrane Flow ◽  
Secretory Cycle ◽  
Microsome Fraction ◽  
Stimulation Of ◽  
Cholinergic Drug

Stimulation of enzyme secretion in the pancreas on injection of a single dose of the cholinergic drug, pilocarpine, was associated with an increased incorporation of [2-3H]myoinositol into a lipid, which was previously characterized as phosphatidylinositol. Stimulation of enzyme secretion by hourly injection of the pancreozymin congener, caerulein, led to more increased phosphatidylinositol synthesis than with a single injection of pilocarpine. The amylase level of the pancreas remained at a low level as long as caerulein was injected, indicating continued stimulation of enzyme secretion even though increased phosphatidylinositol synthesis ceased after 6 h. Feeding gave the same stimulation of phosphatidylinositol synthesis as caerulein. The major synthesis of phosphatidylinositol in controls and the stimulation of phosphatidylinositol synthesis by pilocarpine was entirely confined to the microsome fraction throughout the experiments (up to 18 h). This shows that there is no flow of microsomal membrane (smooth- or rough-surfaced endoplasmic reticulum) to other membranous structures throughout the secretory cycle and beyond. It is concluded that the stimulation of phosphatidylinositol synthesis by pancreatic secretagogues is confined to microsomal elements and does not play any role in membrane flow.

DISSOCIATION OF THE CALORIGENIC ACTION OF THYROID HORMONES FROM THE DEIODINATION OF L-THYROXINE IN VIVO

1965 ◽  
Vol 48 (3) ◽  
pp. 506-512 ◽  
Author(s):  
M. Anbar ◽  
M. Inbar ◽  
J. R. Tata
Keyword(s):  
Thyroid Hormones ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Actinomycin D ◽  
Single Injection ◽  
Small Doses ◽  
Double Isotope ◽  
Stimulation Of

ABSTRACT The rate of deiodination of L-thyroxine was measured in vivo in normal and thyroidectomized rats by a technique of double isotope (125I and 131I) labelling. Small doses of Actinomycin D administered at the same time as 3,5,3′-triiodo-L-thyronine or L-thyroxine almost completely abolished the stimulatory effect of the hormones on basal metabolic rate (B. M. R.) but slightly elevated the rate of deiodination of L-thyroxine. When studied sequentially, the stimulation of B. M. R. preceded the increase in rate of deiodination of the hormone following a single injection of triiodothyronine to thyroidectomized rats. These results suggest that the rate of deiodination is not directly associated with the action of thyroid hormones.

Stimulation of mammogenesis and lactogenesis by recombinant bovine placental lactogen in steroid-primed dairy heifers

1994 ◽  
Vol 140 (1) ◽  
pp. 33-43 ◽  
Author(s):  
J C Byatt ◽  
P J Eppard ◽  
J J Veenhuizen ◽  
T L Curran ◽  
D F Curran ◽  
...  
Keyword(s):  
Serum Concentration ◽  
Steroid Injection ◽  
Mammary Glands ◽  
Negative Control ◽  
Placental Lactogen ◽  
Control Value ◽  
Dairy Heifers ◽  
Total Dna ◽  
Stimulation Of

Abstract A model of induced lactation was modified to examine the effects of bovine prolactin (bPRL) and bovine placental lactogen (bPL) on mammary growth and differentiation. Thirty-two peripubertal, non-pregnant Holstein heifers were given daily s.c. injections of oestradiol (0·05 mg/kg) and progesterone (0·25 mg/kg) for 7 days to initiate mammary growth. Treatment with bromocriptine (40 mg/3 days) reduced serum PRL concentrations to approximately 25% of pretreatment levels, for the duration of the study. On the day following the last steroid injection, groups of eight heifers were given twice daily s.c. injections of either saline (negative control), recombinant bPRL (rbPRL; 80 mg/day) or recombinant bPL (rbPL; 80 and 160 mg/day) for 7 days. At the end of this period (day 15), growth and differentiation of the mammary glands were assessed. Treatment with rbPL increased total mammary DNA above control value by 50 and 60% for the 80 and 160 mg/day doses respectively. However, total DNA was not different for the control and rbPRL-treated groups. The blood serum concentration of α-lactalbumin was measured daily throughout the study and used as an index of mammary differentiation. Both rbPRL and rbPL stimulated mammary differentiation (i.e. induction of milk synthesis), although rbPRL appeared to be more potent than rbPL. These results indicate that rbPL is lactogenic in vivo and strongly suggest that bPL is a mammary mitogen. Journal of Endocrinology (1994) 140, 33–43

Further evidence that protein synthesis can be decreased in vivo following hormonal stimulation in the rat pancreas

1976 ◽  
Vol 54 (3) ◽  
pp. 305-313 ◽  
Author(s):  
R. Mongeau ◽  
J. C. Dagorn ◽  
J. Morisset
Keyword(s):  
Protein Synthesis ◽  
Single Injection ◽  
Protein Biosynthesis ◽  
Specific Radioactivity ◽  
Hormonal Stimulation ◽  
In Vitro System ◽  
Precursor Pool ◽  
Stimulation Of

The present study has been undertaken to determine in the rat the influence of exocrine secretory stimulation on pancreatic protein synthesis. This stimulant consisted of a single injection of cholecystokinin–pancreozymin (8 Ivy units/kg) plus secretin (5 clinical units/kg). The rate of [14C]phenylalanine incorporation into total proteins was measured 5, 11, 17, 30, 45 and 60 min later. Incorporation was significantly decreased after 5 min, then significantly increased at 17 min, and finally returned to control values at 45 min. This biphasic evolution was shown not to be caused by variations in the precursor pool specific radioactivity. We concluded that secretory stimulation of the pancreas can induce a decrease in the rate of protein biosynthesis. This decrease is nevertheless a transient phenomenon, since the rate of biosynthesis was increased at 17 min. These results, obtained from a totally in vivo system, confirm previous data obtained from an in vivo – in vitro system.

Quantifying in vivo dopaminergic D2-receptors Bmax and KdVr with microPET® focus after a single injection of [11C]raclopride

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S649-S649
Author(s):  
Laurent Besret ◽  
Jean-Dominique Gallezot ◽  
Frédéric Dollé ◽  
Philippe Hantraye ◽  
Marie-Claude Grégoire
Keyword(s):  
Single Injection ◽  
D2 Receptors ◽  
Quantifying In

Comparison of Specific Antibody, D-Phe-Pro-Arg-CH2Cl and Aprotinin for Prevention of In Vitro Effects of Recombinant Tissue-Type Plasminogen Activator on Haemostasis Parameters

1987 ◽  
Vol 58 (03) ◽  
pp. 921-926 ◽  
Author(s):  
E Seifried ◽  
P Tanswell
Keyword(s):  
Specific Antibody ◽  
Plasma Concentrations ◽  
Fibrinolytic Therapy ◽  
Tissue Type ◽  
Control Value ◽  
Type Plasminogen Activator ◽  
In Vitro Effects ◽  
Fibrinolytic Parameters

SummaryIn vitro, concentration-dependent effects of rt-PA on a range of coagulation and fibrinolytic assays in thawed plasma samples were investigated. In absence of a fibrinolytic inhibitor, 2 μg rt-PA/ml blood (3.4 μg/ml plasma) caused prolongation of clotting time assays and decreases of plasminogen (to 44% of the control value), fibrinogen (to 27%), α2-antiplasmin (to 5%), FV (to 67%), FVIII (to 41%) and FXIII (to 16%).Of three inhibitors tested, a specific polyclonal anti-rt-PA antibody prevented interferences in all fibrinolytic and most clotting assays. D-Phe-Pro-Arg-CH2Cl (PPACK) enabled correct assays of fibrinogen and fibrinolytic parameters but interfered with coagulometric assays dependent on endogenous thrombin generation. Aprotinin was suitable only for a restricted range of both assay types.Most in vitro effects were observed only with rt-PA plasma concentrations in excess of therapeutic values. Nevertheless it is concluded that for clinical application, collection of blood samples on either specific antibody or PPACK is essential for a correct assessment of in vivo effects of rt-PA on the haemostatic system in patients undergoing fibrinolytic therapy.

EFFECT OF PROPYLTHIOURACIL ON THE IODINATION AND MATURATION OF RAT THYROGLOBULIN

1966 ◽  
Vol 53 (2) ◽  
pp. 271-285 ◽  
Author(s):  
Claude Simon ◽  
Marie Roques ◽  
Janine Torresani ◽  
Serge Lissitzky
Keyword(s):  
Single Injection ◽  
Freezing And Thawing ◽  
Isotopic Equilibrium ◽  
Sedimentation Constant

ABSTRACT The effect of propylthiouracil on the maturation of rat thyroglobulin in vivo has been investigated. Newly iodinated thyroglobulin dimer is labile to freezing and thawing. This observation has been used to interpret the findings in the present experiments. From experiments using rats in isotopic equilibrium with 125I, and treated with propylthiouracil or propylthiouracil and tri-iodothyronine and also given a single injection of 131I, the following conclusions were formulated 1) the appearance of iodinated S12 thyroglobulin monomer is due to the dissociation of labile iodinated thyroglobulin dimer and appears more readily if the dimer is poorly iodinated, 2) uniodinated thyroglobulin dimer is the most probable substrate for iodination in vivo, 3) maturation of thyroglobulin dimer (as shown by increasing sedimentation constant from 16—17 to 19) is accompanied by increasing amounts of iodine in the molecule, 4) it is not possible to say at present if iodination and iodothyronine formation is the cause or the consequence of thyroglobulin dimer maturation, 5) propylthiouracil might inhibit thyroglobulin maturation by decreasing iodine organification.

Stimulation of ovarian progesterone secretion by oxytocin in vivo

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S199-S200
Author(s):  
E. DIETRICH ◽  
K. RENTELMANN ◽  
W. WUTTKE
Keyword(s):  
Progesterone Secretion ◽  
Stimulation Of
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