Ontogeny of adenylate cyclase and phosphodiesterase activities in swine tissues

The ontogenic patterns of the basal- and fluoride-stimulated adenylate cyclase and the cAMP phosphodiesterase activites as well as the tissue levels of cAMP were assessed in swine adipose tissue, heart, skeletal muscle, and liver. The developmental patterns were complex. However, there was a general tendency in all tissues toward lower enzyme activities in the oldest animals (150 days) for both enzymes. In adipose tissue, the decreased enzyme levels could partially be attributed to an increase in adipocyte size.