Alpha-2 adrenergic receptor activity in porcine adipocytes is androgen and age/cell size dependent.

1. Using epinephrine plus propranolol we demonstrated alpha-2 adrenergic receptor (alpha 2AR) activity (49% inhibition of theophylline stimulated lipolysis) in adipocytes of adult intact male pigs (61 kg body wt and 97 microns adipocyte diameter). 2. Dose titration with an alpha 2AR antagonist (yohimbine) confirmed alpha 2AR associated activity. 3. No alpha 2AR activity was observed in younger male or castrated male pigs. 4. The inhibitory action on lipolysis via the alpha 2AR in pigs is dependent on androgen status and adipocyte size or age.