Effect of dibutyryl cyclic AMP on glucagon and insulin storage and secretion in organ culture of rat islets

1975 ◽  
Vol 31 (5) ◽  
pp. 610-612 ◽  
Author(s):  
Brigitte Ziegler ◽  
M. Ziegler ◽  
Renate Mehling
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Dibutyryl Cyclic Amp ◽  
Rat Islets ◽  
Glucagon And Insulin ◽  
Insulin Storage

scholarly journals The effects of glucagon and insulin on adenosine 3′:5′-cyclic monophosphate concentrations in an organ culture of mature rat liver

1973 ◽  
Vol 132 (4) ◽  
pp. 765-773 ◽  
Author(s):  
Kenneth Siddle ◽  
Barbara Kane-Maguire ◽  
Anthony K. Campbell
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Rat Liver ◽  
Incubation Medium ◽  
Radioactive Tracer ◽  
Maximal Increase ◽  
Low Concentrations ◽  
Glucagon And Insulin ◽  
Millipore Filters ◽  
Glucagon Concentration

1. A modified radioimmunoassay for cyclic AMP was developed from the method of Steiner et al. (1969). Cyclic [3H]AMP was used as the radioactive tracer. Free and antibody-bound nucleotides were separated by adsorption of protein to Millipore filters. The assay was used to measure amounts of cyclic AMP down to 0.1pmol in 50μl. 2. The effect of glucagon on cyclic AMP content in pieces of mature rat liver maintained for 6 days in organ culture was studied. 3. Cyclic AMP content in the tissue reached a maximum in 5–15min and then decreased. This may have been partly due to an inhibitor of glucagon action formed in the tissue. Small amounts of cyclic AMP were released into the incubation medium. 4. The maximal increase in cyclic AMP content produced by glucagon decreased over 6 days in culture. However, liver pieces cultured for 2 and 6 days were more sensitive to low concentrations of glucagon than were fresh liver pieces. Glucagon concentrations for half-maximal effects were approx. 1μm and 0.05μm for fresh liver and 2-day cultured liver respectively. 5. Insulin (3.5μm) lowered the cyclic AMP content by 30% in the presence of a submaximal glucagon concentration in liver cultured for 2 days. No effect of insulin was demonstrated on fresh liver pieces. 6. Insulin and glucagon were rapidly destroyed by fresh liver pieces.

scholarly journals Changes in the activities of the enzymes of urea synthesis caused by dexamethasone and dibutyryladenosine 3′:5′-cyclic monophosphate in foetal rat liver maintained in organ culture

1976 ◽  
Vol 160 (2) ◽  
pp. 159-162 ◽  
Author(s):  
E Edkins ◽  
N C R Rïhä
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Rat Liver ◽  
Urea Cycle ◽  
Defined Medium ◽  
Urea Synthesis ◽  
Dibutyryl Cyclic Amp ◽  
Carbamoyl Phosphate ◽  
Foetal Rat ◽  
Ornithine Transcarbamoylase

Liver explants from 19-day foetal rats were maintained in organ culture, in a defined medium, for up to 48h. Both 6-N,2′-O-dibutyryl cyclic AMP, in the presence of theophylline, and dexamethasone caused an increase in the activities of carbamoyl phosphate synthase, argininosuccinate synthetase, argininosuccinate lyase and arginase. These increases could be abolished by simultaneously incubating the explants with cycloheximide. No change in the activity of ornithine transcarbamoylase was found with either hormone. Previous work has shown that injection of corticosteroids into 19.5-day foetal rats in utero did not cause an increase in the arginine synthetase system. Present results suggest that this lack of effect is not due to any incompetence of the foetal rat liver at this stage to respond to this agent. The observations on ornithine transcarbamoylase activity suggest that this enzyme is induced in the liver of the perinatal rat by neither corticosteroids nor hormones acting via cyclic AMP, and it may be that all the enzymes of the urea cycle are induced physiologically by an agent or agents as yet unidentified.

Stimulatory Effect of Isoproterenol but Not of Dibutyryl Cyclic AMP on N-Acetyltransferase Activity and Melatonin Content of Syrian Hamster Pineal Gland in Organ Culture

1988 ◽  
Vol 48 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Celsa Santana ◽  
Juan M. Guerrero ◽  
Russel J. Reiter ◽  
Manuel Puig-Domingo ◽  
Aldo Gonzalez-Brito
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Pineal Gland ◽  
Syrian Hamster ◽  
Dibutyryl Cyclic Amp ◽  
Acetyltransferase Activity

scholarly journals Regulation of tyrosine aminotransferase in foetal rat liver

1980 ◽  
Vol 186 (2) ◽  
pp. 609-612 ◽  
Author(s):  
S M Andersson ◽  
N C Räihä ◽  
J J Ohisalo
Keyword(s):  
Enzyme Activity ◽  
Methyl Ester ◽  
Cyclic Amp ◽  
Organ Culture ◽  
Rat Liver ◽  
Tyrosine Aminotransferase ◽  
Dibutyryl Cyclic Amp ◽  
Adult Rat ◽  
Foetal Rat

A specific tyrosine aminotransferase, separate from the aspartate aminotransferases, is present in low concentration in foetal rat liver at the 21st day of gestation. Intraperitoneal injections of tyrosine methyl ester into the foetuses in utero increase the activity 2-fold, whereas glucose injections decrease it. Tyrosine, dexamethasone and dibutyryl cyclic AMP induce the enzyme activity in organ culture to the same extent as in adult rat liver in vivo.

The inhibitory effects of some adenosine nucleolipids on the lipolysis in rat epididymal fat pads in vitro

1979 ◽  
Vol 44 (5) ◽  
pp. 1651-1656 ◽  
Author(s):  
Sixtus Hynie ◽  
Jiří Smrt
Keyword(s):  
Fatty Acids ◽  
Cyclic Amp ◽  
Dibutyryl Cyclic Amp ◽  
Inhibitory Effects ◽  
Epididymal Fat ◽  
Fat Pads

3'-Oleolyl-2,3-dihydroxypropyl-AMP, 3'-stearoyl-2,3-dihydroxypropyl-AMP, octadecyl-AMP and palmitamidoethyl-AMP inhibited in comparison with adenosine or fatty acids much stronger the lipolysis in rat epididymal fat pads in vitro stimulated by isoproterenol, theophylline and dibutyryl cyclic AMP. The inhibition of the effects of the two latter drugs suggest that the described effect is caused not only by the inhibition of the cyclic AMP production but also by the inhibition of its effect on the following steps in process of lipolysis.

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