Evidence for the presence of several phosphodiesterase isoforms in brown adipose tissue of Zucker rats: modulation of PDE2 by the fa gene expression

The present study was undertaken to characterise the phosphodiesterases (PD Es) present in brown adipose tissue (BAT) of Zucker rat pups and to determi ne whether the capacity for degradation of cyclic nucleotides was affected hy the fatty genotype, Regardless of the genotype, PDE2-4 contributed to to tal PDE activity, the PDE3 activity equalling the sum of PDE2 and 4 activit ies. In fa/fa compared to Fa/fa rats, (a) PDE2 activity was significantly i ncreased, (b) Western blot analysis of PDE2 revealed two signals at 71 and 105 kDa, with changes in protein being in good parallelism with changes in activity, (c) the PDE2 mRNA concentration was also significantly increased. In good agreement, the cGMP concentration was decreased in BAT from fa/fa pups, (C) 1999 Federation of European Biochemical Societies.