Summary
The role of thyroid hormones on lipolysis in human subcutaneous adipose tissue was
investigated. Incubation of subcutaneous fat pads with thyroxine (0.1-10000 nM) augmented
the subsequent isoproterenol stimulation of lipolysis, measured by glycerol release.
The basal lipolysis could not be stimulated by thyroxine. The theophylline- and dibutyryl-cyclic
AMP stimulated lipolysis also could not be increased by thyroxine at these concentrations.
In separate studies, the effect of thyroxine (0.01 pM-1 μM) and triiodothyronine (0.01
pM-1 μM) on cyclic AMP accumulation was examined. No effect of thyroid hormones on
cyclic AMP accumulation was seen in non-isoproterenol stimulated tissue. Fat pads
stimulated by isoproterenol and then treated with thyroid hormones showed marked increases
in accumulation of cyclic AMP as compared to control tissue in the presence of isoproterenol
alone.
