Failure of parathormone to affect insulin and glucagon release from the perfused rat pancreas.

Parathormone (0.15 U/ml) failed to affect the rate of glucagon and insulin release by the perfused rat pancreas exposed to glucose in either low (3.3 mM) or high (8.3 mM) concentration. Parathormone also failed to interfere with the suppressive effect of glucose (16.6mM) upon glucagon release and its stimulatory action upon insulin secretion. Likewise, the biphasic release of both glucagon and insulin evoked by arginine (10.0 mM) in the presence of glucose (8.3 mM) was unaffected by parathormone. These findings suggest that the endocrine pancreas may not be a target organ for any direct and immediate action of parathormone.