Regulation of lipolysis and leptin biosynthesis in rodent adipose tissue by growth hormone

The present study examined the effects of growth hormone (GH) on lipolysis and leptin release by cultured adipose tissue from rats and mice incubated for 24 hours in primary culture. A stimulation of leptin release by GH in r at adipose tissue was found in the presence of 25 nmol/L dexamethasone, and this was accompanied by a 28% increase in leptin mRNA content. GH stimulat ed lipolysis in rat adipose tissue in the presence of 0.1 nmol/L CL 316,249 , In contrast, basal lipolysis in mouse adipose tissue was stimulated by GH , but this was not accompanied by an increase in leptin release. However, i n the presence of insulin plus triiodothyronine (T-3), the stimulation of l ipolysis by GH was abolished and GH increased leptin release. These results indicate that GH can stimulate leptin release by both mouse and rat adipos e tissue in the absence of a stimulation of lipolysis, In contrast, under c onditions in which lipolysis is stimulated by GH, there is no effect on lep tin release, Copyright (C) 2000 by W.B. Saunders Company.