Adenosine and the control of lipolysis in rat adipocytes during pregnancy and lactation.
The rate of noradrenaline-stimulated lipolysis is lower in fat-cells from lactating than from pregnant rats; this difference is eliminated by the addition of adenosine deaminase [Aitchison, Clegg & Vernon (1982) Biochem. J. 202, 243-247]. The activity of 5'-nucleotidase, and hence the capacity of the cells to synthesize adenosine, was the same in fat-cells and also stromal cells of adipose tissue from pregnant, lactating and male rats. The response and sensitivity of fat-cells to the anti-lipolytic effects of adenosine were measured by incubating cells in the presence of noradrenaline, adenosine deaminase (to remove endogenous adenosine) and various concentrations of the adenosine analogue N6-phenylisopropyladenosine (PIA). PIA caused a greater inhibition of the rate of noradrenaline-stimulated lipolysis in adipocytes from lactating than from pregnant rats. The concentration of PIA required to inhibit by 50% the rate of noradrenaline-stimulated lipolysis fell from over 100 nM for fat-cells from pregnant rats to 30 nM for fat-cells from lactating rats. The decreased rate of noradrenaline-stimulated lipolysis during lactation was not due to the smaller mean cell volume of adipocytes during this state.
D015720:5'-Nucleotidase; D000241:Adenosine / Q000378:metabolism*; D000243:Adenosine Deaminase / Q000378:metabolism; D000248:Adenosine Kinase / Q000378:metabolism; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D004247:DNA / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D007774:Lactation; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D009708:Nucleotidases / Q000378:metabolism; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D011506:Proteins; D010660:Phenylisopropyladenosine; D004247:DNA; D000248:Adenosine Kinase; D009708:Nucleotidases; D015720:5'-Nucleotidase; D000243:Adenosine Deaminase; D000241:Adenosine