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Cyclic AMP and free fatty acids in the longer-term regulation of pyruvate dehydrogenase kinase in rat soleus muscle.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 1992 Jun 10; Vol. 1135 (2), pp. 201-6. - Publication Year :
- 1992
-
Abstract
- Starvation increased pyruvate dehydrogenase (PDH) kinase activity in extracts of freshly excised rat soleus 2.2-fold (from 0.6 min-1 in fed rats to 1.31 min-1 in 48-h-starved rats). In fed rats, activities were unchanged following 24 h of culture in medium 199, but increased 2.1-fold on 24 h of culture with 50 microM dibutyryl cAMP plus 1 mM n-octanoate and 1.6-1.7-fold with either agent alone. Approx. 70% of the increase in PDH kinase induced by starvation was lost following 24 h of culture in medium 199; the loss was prevented by 50 microM dibutyryl cAMP plus 1 mM n-octanoate. cAMP concentrations in fresh soleus muscle were 1 nmol/g (fed rats) and 1.6 nmol/g (starved rats). After 20-60 min of culture the fed-starved difference disappeared and [cAMP] fell to 0.4 nmol/g. Calcitonin-gene-related peptide (CGRP) increased cAMP 3-fold; the increase was maintained throughout 24 h of culture, but was readily reversed at 30 min or 24 h of culture by 60-min incubation with CGRP-free medium. Starvation of the rat (48 h) had no effect on the sensitivity of soleus towards the [cAMP]-increasing effect of CGRP. It is concluded that culture may reverse effects of starvation on PDH kinase activity by lowering cAMP and by removal from the in vivo effects of circulating free fatty acids; and that starvation and CGRP had no detectable long-term effects on the cAMP system in soleus muscle.
- Subjects :
- Adenosine Deaminase pharmacology
Amyloid pharmacology
Animals
Calcitonin Gene-Related Peptide pharmacology
Caprylates pharmacology
Citrate (si)-Synthase metabolism
In Vitro Techniques
Insulin pharmacology
Islet Amyloid Polypeptide
Muscles enzymology
Protein Kinases isolation & purification
Protein Serine-Threonine Kinases
Pyruvate Dehydrogenase Acetyl-Transferring Kinase
Rats
Starvation enzymology
Theophylline analogs & derivatives
Theophylline pharmacology
Triiodothyronine pharmacology
Bucladesine pharmacology
Fatty Acids, Nonesterified pharmacology
Muscles drug effects
Protein Kinases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 1135
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 1319745
- Full Text :
- https://doi.org/10.1016/0167-4889(92)90137-z