Effect of insulin and lipolytic agents on rat adipocyte low Km cyclic adenosine 3':5'-monophosphate phosphodiesterase.

摘要: Abstract Isolated rat fat cells were incubated with insulin or lipolytic agents and measurements made of the activity low Km cyclic adenosine 3' : 5'-monophosphate (cyclic AMP) phosphodiesterase in subsequently prepared fat-free homogenates. In assay [3H]adenosine production from cyclic[3H]AMP was measured. Insulin consistently increased Vmax, did not alter (0.3 µm), ineffective when added to As little as 7.5 microunits per ml by 18% 50 produced maximum stimulation 65%. Incubation isoproterenol, epinephrine, adrenocorticotropic hormone 20 30 %. The effect hormones on could be reproduced 2.0 mm N6, O2'-dibutyryl 5'-monophosphate. apparent within 2 min, at 5 sustained for least 60 min. response isoproterenol equally rapid, reaching a peak 10 min but sustained. fall observed apparently related intracellular ATP depletion. Homogenates preincubated separated into 50,000 x g particulate supernatant fractions. associated fraction increased, while that unaffected hormonal preincubation. These data suggest antilipolytic may mediated through activation phosphodiesterase. well, responsible failure these produce increases adipocyte AMP.