Lipolytic response of bovine adipose tissue to alpha and beta adrenergic agents 30 days pre- and 120 days postpartum.

1. The beta adrenergic agonists isoproterenol and epinephrine stimulated in vitro lipolysis in adipose tissue removed from heifers 30 days pre- and 120 days postpartum. 2. Propranolol, a beta antagonist, blocked isoproterenol stimulated lipolysis pre- and postpartum. 3. Epinephrine co-incubated with propranolol resulted in a suppression of lipolysis similar to that produced by clonidine, an alpha agonist, both pre- and postpartum. 4. Bovine adipose tissue lipolysis was more responsive to isoproterenol and isoproterenol + propranolol at 120 days of lactation than 30 days prepartum. 5. Adipose tissue sensitivity to clonidine, epinephrine and epinephrine + propranolol did not differ 30 days pre- and 120 days postpartum.