Insulin and lipolytic hormones stimulate the same phosphodiesterase isoform in rat adipose tissue.
Insulin sensitive phosphodiesterase from rat adipocytes is found in particulate fractions. Solubilisation of the enzyme with triton X-100 yields a preparation containing more than one phosphodiesterase activity as judged by its rate of thermal denaturation at 45 degrees C and by its non-linear kinetic plots. Immunoprecipitation of solubilised activity with a polyclonal antiserum raised against purified insulin-sensitive rat liver phosphodiesterase selected a form of the enzyme which showed a single exponential decay of enzyme activity when heated at 45 degrees C and linear low Km kinetics. Treatment of adipocytes with insulin ACTH, glucagon or isoproterenol stimulated the low Km particulate phosphodiesterase. The hormonal activation was retained following solubilisation and was also seen when activity was immunoprecipitated. It is suggested that all four hormones activate the same form of phosphodiesterase.
Boyes
S
S
Department of Clinical Biochemistry, University of Otago Medical School, Dunedin, New Zealand.
Loten
E G
EG
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000273:Adipose Tissue / Q000187:drug effects / Q000201:enzymology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005934:Glucagon / Q000494:pharmacology*; D007163:Immunosorbent Techniques; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008066:Lipolysis; D008099:Liver / Q000201:enzymology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D002316:Cardiotonic Agents; D007328:Insulin; D007527:Isoenzymes; D000324:Adrenocorticotropic Hormone; D005934:Glucagon; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D006152:Cyclic GMP; D007545:Isoproterenol