STUDIES ON ISOLATED RAT ADRENAL CELLS I. CONTINUOUS FLOW AND BATCH INCUBATIONS

1975 ◽  
Vol 78 (1) ◽  
pp. 110-121 ◽  
Author(s):  
H. E. Falke ◽  
H. J. Degenhart ◽  
G. J. A. Abeln ◽  
H. K. A. Visser ◽  
R. J. M. Croughs
Keyword(s):  
Production Rate ◽  
Continuous Flow ◽  
Response Curve ◽  
Steroid Biosynthesis ◽  
Adrenal Cells ◽  
Flow Apparatus ◽  
Lag Period ◽  
Number Of Cells ◽  
Isolated Rat

ABSTRACT A procedure for the continuous flow incubation of isolated adrenal cells is described. In this way the advantages of continuous flow incubations of adrenal tissue are combined with those of isolated adrenal cells. Suspensions of isolated adrenal cells were prepared by a modification of the collagenase method. A sigmoid dose-response curve was obtained when these cells were incubated with ACTH in batch incubations. Under these conditions (in the presence of 1 mU ACTH/ml) the corticosterone production rate remained constant during at least 240 min. This production rate was linearly related to the number of cells. Pre-incubation of the cells during 3 h resulted in an increased response to ACTH. In continuous flow incubations without ACTH the corticosterone production was negligible. With 100 μU ACTH/ml corticosterone production increased sharply after a short lag period. A maximum was reached after 60–75 min followed by a slow decrease. Cells pre-incubated in the continuous flow apparatus had a slightly diminished ACTH response without loss of affinity to ACTH. The continuous flow incubation of isolated adrenal cells offers new possibilities for the dynamic study of steroid biosynthesis in vitro. The method may also be valuable to study processes in a wide variety of other tissues.

THE ASSAY OF INSULIN IN VITRO BY MEANS OF THE GLUCOSE UPTAKE OF THE ISOLATED RAT DIAPHRAGM

1956 ◽  
Vol 14 (1) ◽  
pp. 82-86 ◽  
Author(s):  
P. J. RANDLE
Keyword(s):  
Glucose Uptake ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Rat Diaphragm ◽  
Minimum Concentration ◽  
Isolated Rat

SUMMARY An in vitro method of insulin assay based upon the glucose uptake of the isolated rat diaphragm is described and a statistical appraisal of the method given. The minimum concentration of insulin which was detected by this method was of the order of 10−4 i.u. of insulin/ml. The index of precision (λ) varied in eighteen studies of regression from 0·18 to 0·74. The slope of the log dose-response curve was found to vary significantly from experiment to experiment. The results are briefly compared with those obtained with other in vitro methods of insulin assay.

Plasminogen Activation in Diabetes Mellitus: Normalization of Blood Sugar Levels Improves Impaired Enzyme Kinetics In Vitro

1985 ◽  
Vol 54 (02) ◽  
pp. 413-414 ◽  
Author(s):  
Margarethe Geiger ◽  
Bernd R Binder
Keyword(s):  
Plasminogen Activator ◽  
Blood Sugar ◽  
Metabolic Disorders ◽  
Normal Values ◽  
Diabetic Patients ◽  
Type I ◽  
Plasminogen Activation ◽  
Lag Period ◽  
Sugar Levels

SummaryWe have demonstrated previously that fibrin enhanced plasmin formation by the vascular plasminogen activator was significantly impaired, when components isolated from the plasma of three uncontrolled diabetic patients (type I) were used to study plasminogen activation in vitro. In the present study it can be demonstrated that functional properties of the vascular plasminogen activators as well as of the plasminogens from the same three diabetic patients are significantly improved after normalization of blood sugar levels and improvement of HbAlc values. Most pronounced the Km of diabetic vascular plasminogen activator in the presence of fibrin returned to normal values, and for diabetic plasminogen the prolonged lag period until maximal plasmin formation occurred was shortened to almost control values. From these data we conclude that the observed abnormalities of in vitro fibrinolysis are not primarily associated with the diabetic disease, but might be secondary to metabolic disorders caused by diabetes.

SENSITIVITY OF THE RAT DIAPHRAGM TO GROWTH HORMONE.

1967 ◽  
Vol 54 (4) ◽  
pp. 645-662 ◽  
Author(s):  
Å. Hjalmarson ◽  
K. Ahrén
Keyword(s):  
Growth Hormone ◽  
Inhibitory Effect ◽  
Rat Diaphragm ◽  
Intracellular Accumulation ◽  
Slight Effect ◽  
Kidney Capsule ◽  
Muscle Tissues ◽  
Hypophysectomized Rats ◽  
Isolated Rat

ABSTRACT The effect of growth hormone (GH) in vitro on the rate of intracellular accumulation of the non-utilizable amino acid α-aminoisobutyric acid (AIB) was studied in the intact rat diaphragm preparation. Bovine or ovine GH (25 μg/ml incubation medium) markedly stimulated the accumulation of AIB-14C by diaphragms from hypophysectomized rats, while there was no or only a very slight effect on diaphragms from normal rats. In diaphragms from rats with the pituitary gland autotransplanted to the kidney capsule GH in vitro stimulated the accumulation of AIB-14C significantly more than in diaphragms from normal rats but significantly less than in diaphragms from hypophysectomized rats. Injections of GH intramuscularly for 4 days to hypophysectomized rats made the diaphragms from these rats less sensitive or completely insensitive to GH in vitro. These results indicate strongly that the relative insensitivity to GH in vitro of diaphragms from normal rats is due to the fact that the muscle tissues from these rats has been exposed to the endogenously secreted GH. The results show that GH can influence the accumulation of AIB-14C in the isolated rat diaphragm in two different ways giving an acute or »stimulatory« effect and a late or »inhibitory« effect, and that it seems to be a time-relationship between these two effects of the hormone.

CORTICOSTEROID-UMSATZ UND CORTICOSTEROID-PRODUKTION BEI RATTEN UNTER DER BEHANDLUNG MIT ANABOLEN STEROIDEN

1965 ◽  
Vol 48 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Herbert Schriefers ◽  
Gerlinde Scharlau ◽  
Franzis Pohl
Keyword(s):  
Production Rate ◽  
Adult Female ◽  
Anabolic Steroids ◽  
Reduction Rate ◽  
Female Rats ◽  
Adrenal Weight ◽  
Hydrogenase Activity ◽  
Anabolic Effect ◽  
Liver Slices

ABSTRACT After the administration of anabolic steroids to adult female rats in daily doses of 1 mg per animal for 14 days, the following parameters were investigated: the rate of the Δ4-5α-hydrogenase-catalyzed cortisone reduction in liver slices and microsomal fractions, the adrenal weight and the in vitro corticosterone production rate. Among the steroids tested, only 17α-methyl-testosterone and 17α-ethyl-19-nor-testosterone were effective in lowering significantly cortisone reduction rate by liver slices with concomitant decreases in microsomal Δ4-5α-hydrogenase-activity. Testosterone, 19-nor-testosterone, 17α-ethinyl-19-nor-testosterone, 17α-methyl-17β-hydroxy-androsta-1,4-dien-3-one and 1-methyl-17β-hydroxy-androst-1-en-3-one were ineffective or only slightly effective. Adrenal weight and absolute corticosterone production rate (μg/60 min per animal) were decreased after treatment with 17α-methyl-testosterone, 17α-ethyl-19-nor-testosterone and 1-methyl-17β-hydroxy-androst-1-en-3-one. Corticosterone production was decreased with 17α-ethinyl-19-nor-testosterone in spite of an unchanged adrenal weight. The relative corticosterone production rate (μg/60 min · 100 mg adrenal) was in any cases unaffected. According to these results there exists – with the exception of 17α-ethinyl-19-nor-testosterone – a strict parallelism between corticosteroid turnover and corticosterone production rate: unchanged turnover is correlated with unchanged corticosterone production rate, while a decreased turnover is correlated with decreased adrenal activity. The protein-anabolic effect of certain anabolic steroids may be partly due to an anti-catabolic action of these compounds resulting from a decreased corticosteroid inactivation and production rate. Possible mechanisms by which anabolic steroids may affect corticosteroid-balance are discussed.

Characterization and Screening of a Novel Multiparticulate Pulsatile Delivery of Aceclofenac

2016 ◽  
Vol 9 (5) ◽  
pp. 3494-3501
Author(s):  
Bipul Nath ◽  
Santimoni Saikia
Keyword(s):  
Drug Release ◽  
Sodium Alginate ◽  
Alginate Beads ◽  
In Vitro Drug Release ◽  
Dsc Studies ◽  
Ft Ir ◽  
Lag Period ◽  
Pulsatile Delivery ◽  
Ca Alginate

In the present investigation, sodium alginate based multiparticulate system overcoated with time and pH dependent polymer was studied in the form of oral pulsatile system to achieve pulsatile with sustained release of aceclofenac for chronotherapy of rheumatoid arthritis seven batches of micro beads with varying concentration of sodium alginate (2-5 %) were prepared by ionotropic-gelation method using CaCl2 as cross-linking agent. The prepared Ca-alginate beads were coated with 5% Eudragit L100 and filled into pulsatile capsule with varying proportion of plugging materials. Drug loaded microbeads were investigated for physicochemical properties and drug release characteristics. The mean particle sizes of drug-loaded microbeads were found to be in the range 596±1.1 to 860 ± 1.2 micron and %DEE in the range of 65-85%. FT-IR and DSC studies revealed the absence of drug polymer interactions. The release of aceclofenac from formulations F1 to F7 in buffer media (pH 6.8) at the end of 5h was 65.6, 60.7, 55.7, 41.2, 39.2, 27 and 25% respectively. Pulsatile system filled with eudragit coated Ca-alginate microbeads (F2) showed better drug content, particle size, surface topography, in-vitro drug release in a controlled manner. Different plugging materials like Sterculia gum, HPMC K4M and Carbopol were used in the design of pulsatile capsule. The pulsatile system remained intact in buffer pH 1.2 for 2 hours due to enteric coat of the system with HPMCP. The enteric coat dissolved when the pH of medium was changed to 7.4. The pulsatile system developed with Sterculia gum as plugging material showed satisfactory lag period when compared to HPMC and Carbopol.

scholarly journals Co-culture of monocytes and zona fasciculata adrenal cells: An in vitro model to study the immune-adrenal cross-talk

2021 ◽  
Vol 526 ◽  
pp. 111195
Author(s):  
Daniel P. Fudulu ◽  
George Horn ◽  
Georgina Hazell ◽  
Anne-Marie Lefrançois-Martinez ◽  
Antoine Martinez ◽  
...  
Keyword(s):  
Cross Talk ◽  
In Vitro Model ◽  
Zona Fasciculata ◽  
Adrenal Cells ◽  
Vitro Model

The Hep G2 Cell Line as a Possible Alternative to Isolated Hepatocytes in Cytotoxicity Studies

1988 ◽  
Vol 16 (1) ◽  
pp. 16-22
Author(s):  
Marina Marinovich ◽  
Jose L. Lorenzo ◽  
Liliana M. Flaminio ◽  
Agnese Granata ◽  
Corrado L. Galli
Keyword(s):  
Cell Line ◽  
Rat Hepatocytes ◽  
Prostaglandin E ◽  
Human Hepatoma ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Isolated Rat Hepatocytes ◽  
G2 Cells ◽  
Isolated Rat

The hepatotoxicity of carbon tetrachloride (CC14) was evaluated in vitro in freshly isolated rat hepatocytes and in the human hepatoma cell line, Hep G2. Toxicity was assessed by the leakage of cytosolic enzymes (lactate dehydrogenase and aspartate aminotransferase) and cell viability (trypan blue exclusion). The established human cells were less sensitive to CCl4-induced injury; higher doses of the toxic agent and longer incubation times were necessary to elicit cell damage. Micromolar concentrations of prostaglandin E2 significantly decreased enzyme leakage in both Hep G2 cells and rat hepatocytes challenged with CC14; a stable derivative of prostacyclin (ZK 36374) was ineffective. These results suggest that human hepatoma Hep G2 cells may represent a valid alternative to isolated rat hepatocytes for an initial approach to the in vitro evaluation of cell toxicity.

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