Reduction in hypertension-induced protein synthesis in the rat pulmonary trunk after treatment with teprotide (SQ 20881)

Angiotensin II has been previously implicated as a mediator of vasoconstriction during the development of hypoxic pulmonary hypertension. The effect of angiotensin-converting Enzyme inhibition with teprotide (SQ 20881) on development of pulmonary hypertension was determined by measurement of the drug's ability to modify hypertension-induced protein synthetic changes in the rat pulmonary trunk. Rats were injected with either SQ 20881 (2 mg/kg body wt every 8 hr) or saline vehicle during exposure to chronic hypoxia at 0.5 ATM for either 3 or 7 days. Comparisons were made of tissue weight, absolute protein content, and in vitro synthesis of collagen and noncollagen protein of the pulmonary trunks of SQ-treated hypoxic, SQ-treated normoxic, saline-treated hypoxic, and saline-treated normoxic rats. Treatment of hypoxic rats with SQ 20881 was found to significantly decrease right ventricular pressure, tissue weight, absolute protein content, and in vitro protein synthesis after 7 days compared to saline-treated hypoxic rats. Neither right ventricular hypertrophy nor the development of polycythemia was decreased by SQ 20881 treatment.