[Hemodynamic effects after i.v. application of thyrotropin releasing factor (author's transl)].

20 patients and normal volunteers submitting to a right side heart catheterization have been subjected to hemodynamic tests before and after rapid i.v. injection of synthetic thyrotrophin releasing factor (TRF, Ro 08-6270). 10 persons among a first group were fully informed about the test, i.e. the exact time of injection, 10 others among a second group were not. A statistically significant rise of the arterial blood pressure and heart rate at an average 1-min interval after injection could be demonstrated. After 5 min the effect had completely vanished. The mean pulmonary arterial pressure like other hemodynamic parameters, the blood sugar and cholesterol did not change. A placebo-like effect could not be shown among a third group receiving only the added solvent. Because of the short interval after which the effect occurred, a determinant role of the hypothalamic-pituitary-thyroid feed back is very unlikely. A direct stimulus of TRF to smooth muscle cells of arterial walls responsible for vascular resistance in systemic vessels may be suggested as a hypothesis.