REGIONAL DIFFERENCES IN PROSTAGLANDIN PRODUCTION-RATES AMONG PORCINE INTRATHORACIC VESSELS

To investigate the regional variability in intrathoracic vascular pros taglandin (PG) synthesis, we obtained vessel segments from porcine cor onary artery (COA), thoracic aorta (AT), common carotid artery (CRA), pulmonary artery (PA), pulmonary vein (PV), and inferior vena cava (IV C). Vascular production rates of 6-keto-PGF(1 alpha) (an indicator for PGI(2)), PGF(2 alpha) and PGE(2) were measured both in unstimulated s tate and in arachidonic acid-stimulated state using immunosorbent assa ys. Our results indicated that PGI(2) production rate in all vessel se gments decayed with time after vessel dissection. In all vessel segmen ts tested under unstimulated conditions, PGI(2) production rates were about one order of magnitude higher than PGF(2 alpha) and PGE(2) produ ction rates of the same specimens. Results from unstimulated, 1.5 hr p re-incubated specimens indicated that i) PGI(2) production rates in CO A, AT, and PV were greater than those in CRA, PA, and IVC; ii) PGF(2 a lpha) production rates from the same specimens were higher in PV than in AT, CRA, and IVC, while these in PA were higher than in IVC; and ii i) PGE(2) production rates from the same specimens were not significan tly different from one another. Arachidonic acid added at about 1.5 hr after vessel harvest stimulated the PGI(2) and PGF(2 alpha) synthesis rates by 3 to 15 folds. However, this arachidonic acid treatment caus ed 70 to 300-fold increases in PGE(2) production rates, reaching level s comparable to PGI(2). All three prostanoid production rates under st imulated conditions were also variable among different intrathoracic v essels. Although either physiological gas concentrations or local hemo dynamic conditions alone can partially explain our results, which phys iological parameter(s) actually causes these regional differences rema ins to be verified.