Figure 1.

Growth hormone (GH) and placental lactogen (PL), but not prolactin (PRL), induced relaxation in precontracted isolated rat aortic rings in a dose-dependent manner. Representative physiological recordings of tension, in grams (g), in response to 0.1–100 nmol/L of (B) GH, (C) PL, and (D) PRL. (A) Results are expressed as the percentages (%)±SEM of the relaxation [% of contraction in response to 2 μmol/L phenylephrine (Phe)] induced by GH, PL, and PRL. The insert at the top left represents the % of contraction induced by PRL during the transient contraction that occurred prior to the relaxation. +E, in the presence of the endothelium. n=5 animals in each group. ^bP<0.05 vs GH and PL.