Further studies on the regulation of insulin and growth hormone secretion in the sheep.

Abstract

Epinephrine infusions (0.5–1.0 μg/kg/min) inhibited the insulin secretory response to the short-chain fatty acids propionate (0.5 mmole/kg) and butyrate (0.5 mmole/kg) and intravenous arginine (12.5 g). This inhibitory effect of epinephrine was blocked by alpha adrenergic receptor blockade (i.e., phentolamine) but not by beta adrenergic receptor blockade (i.e., propranolol). Epinephrine also completely abolished the plasma growth hormone response to arginine infusions. This effect was not altered by alpha adrenergic receptor blockade sufficient to reverse the inhibitory effect of epinephrine on insulin secretion. A significant increase (i.e., 5- to 10-fold) in plasma growth hormone was consistently noted 30–60 min after stopping the infusion of epinephrine. Short-chain fatty acids were demonstrated to stimulate insulin secretion in the newborn lamb, which at birth is monogastric and does not have a functioning forestomach. This result indicates that the capacity of the ruminant to respond to shortchain fa...