Insulin and (or) dexamethasone effectson leptin production and metabolic activitiesof ovine adipose tissue explants

Yannick Faulconnier , Carole Delavaud , Yves Chilliard

The in vitro effects of insulin and/or dexamethasone (DEX) on leptin production were studied on adipose tissue (AT) from adult non-lactating, non-pregnant ewes. Perirenal AT explants were incubated for 2 or 4 days and leptin production was determined using a specific ovine RIA. The effects of these hormones were simultaneously measured on glucose and acetate utilisation and on lipogenic enzyme activities. A preliminary dose-response study showed a maximal leptin production by the addition in the incubation medium of 2 mIU$\cdot$mL$^{-1}$ of insulin and 100 nM of DEX. By using these concentrations, insulin or DEX increased leptin production by ovine AT explants whatever the incubation duration and the effects of these two hormones were additive. Insulin also increased substrate utilisation as well as lipogenic enzyme activities while DEX decreased substrate utilisation and did not change the lipogenic enzyme activities. To conclude, leptin response to DEX is specific and largely independent of the overall metabolic or lipogenic activity.

Mots clés: ewe; adipose tissue; leptin; insulin; dexamethasone

Domaines: Biologie de la reproduction; Alimentation et Nutrition; Biologie du développement

Yannick Faulconnier, Carole Delavaud, Yves Chilliard. Insulin and (or) dexamethasone effectson leptin production and metabolic activitiesof ovine adipose tissue explants. Reproduction Nutrition Development, 2003, 43 (3), pp.237-250. ⟨10.1051/rnd:2003018⟩. ⟨hal-00900446⟩