Comparative study of hydrogen and aminopyrine clearance methods for determination of gastric mucosal blood flow in dogs.

Effects of pentagastrin, histamine, PGI2, and vasopressin on gastric mucosal blood flow (GMBF) in innervated stomaches of anesthetized dogs were measured by means of the hydrogen clearance method, using a contact electrode. The results were compared with findings obtained with the aminopyrine (AP) clearance method in Heidenhain pouch preparations. Pentagastrin at 2 and 8 micrograms/kg/hr had no effects on GMBF, as measured by the hydrogen clearance method, but there was a marked increase in GMBF when the AP clearance method was used. Histamine at 40 or 160 micrograms/kg/hr tended to reduce or significantly reduced GMBF when measured with the hydrogen clearance method, but there was a significant increase in GMBF with the AP clearance method. Both PGI2 (3 or 30 micrograms/kg/hr) and vasopressin (0.06 or 0.25 units/kg/hr) reduced GMBF as determined by both methods. These results indicate that the hydrogen clearance method is advantageous for detecting regional GMBF but is disadvantageous when attempting to detect the effects of agents which increase GMBF.