Effect of insulin and glucagon on the mobility of ESR-probes incorporated in rat liver plasma membranes.
1. The effect of different concentrations of insulin (INS) and glucagon (GLU) on the rotational mobility of a membrane-incorporated spin probe 2,2-6,6-tetramethyl-4-capriloyl piperidine-1-oxil (C7) was investigated by electron spin resonance (ESR) technique. 2. Two strong adenylate cyclase effectors guanosine 5'-triphosphate (GTP) and guanylyl 5'-imidodiphosphate [Gpp(NH)p], as well as an antioxidant 4-methyl-2,6-ditretbutilphenol (AO) and a nonprotein hormone prostaglandin E2 (PGE2) were used as reference effectors. 3. Applied effectors reduced by 30-82% the rotation correlation time (TR) of the rat liver plasma membranes spin probe C7. The effect was time-dependent and reached saturation 30-40 min after the effector application. 4. The kinetic- and concentration-dependent changes in TR were described by a simple phenomenological model. The apparent binding constants and the number of the apparent membrane binding sites of the effectors used were calculated using the model.
Central Lab of Biophysics, Bulgarian Academy of Sciences, Sofia.
I
I
Zlatanov
E
E
Maltzeva
N
N
Borovok
V
V
Spassov
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D002210:Caprylates; D002462:Cell Membrane / Q000378:metabolism; D003497:Cyclic N-Oxides; D015232:Dinoprostone / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation; D005934:Glucagon / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008560:Membrane Fluidity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013113:Spin Labels
D002210:Caprylates; D003497:Cyclic N-Oxides; D007328:Insulin; D013113:Spin Labels; C083049:2,2,6,6-tetramethyl-4-capryloylpiperidine-1-oxyl; D002084:Butylated Hydroxytoluene; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D005934:Glucagon; D000262:Adenylyl Cyclases; D015232:Dinoprostone