Effects of castration, dietary fat and adipose tissue sites on adipocyte plasma-membranes cyclic AMP phosphodiesterase activity in the pig.
1. cAMP Phosphodiesterase activity and kinetic parameters (Km and Vmax) were measured in subcutaneous and perirenal adipocyte plasma membranes from Large White male and castrated pigs. The animals were fed a control low fat diet or a sunflower diet enriched with linoleic acid (C18:2 n-6). 2. Phosphodiesterase activity, low Km and Vmax were lowered by castration. 3. In animals fed the sunflower diet, phosphodiesterase activity decreased without affecting either Km or Vmax. 4. Phosphodiesterase activity was higher in perirenal sites than in subcutaneous ones, particularly in male pigs. This may be explained by a lower Km or a higher cAMP phosphodiesterase affinity to cAMP in perirenal sites. 5. Theophylline was a potent inhibitor of phosphodiesterase activity principally in perirenal sites. 6. The intermediate role of cAMP phosphodiesterase in adenylate cyclase activity and lipolytic processes is discussed.
Benmansour
N
N
Laboratoire de Nutrition et Sécurité Alimentaire, INRA, Centre de Recherches de Jouy-en-Josas, France.
Demarne
Y
Y
Lecourtier
M J
MJ
Lhuillery
C
C
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002369:Castration; D002462:Cell Membrane / Q000201:enzymology*; D004041:Dietary Fats / Q000494:pharmacology*; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids; D008297:Male; D010938:Plant Oils; D012867:Skin / Q000166:cytology / Q000378:metabolism; D000074242:Sunflower Oil; D013552:Swine; D013737:Testis / Q000502:physiology*; D013806:Theophylline / Q000494:pharmacology
D004041:Dietary Fats; D008041:Linoleic Acids; D010938:Plant Oils; D000074242:Sunflower Oil; D019787:Linoleic Acid; D013806:Theophylline; D015105:3',5'-Cyclic-AMP Phosphodiesterases