Plasma GHRH, CRH, ACTH, β-endorphin, human placental lactogen, GH and cortisol concentrations at the third trimester of pregnancy

Abstract

Abstract. The aim of the study was to determine the concentration of GHRH and CRH in maternal plasma during the 3rd trimester of pregnancy and to search for the possible correlations with related hormones such as ACTH, β-endorphin, cortisol, GH and human placental lactogen. Patients consisted of 31 healthy pregnant women (20–39 years) divided according to duration of pregnancy into 2 groups: I. from 26 to 32 pregnancy week N = 13), II. from 33 to 39 week (N = 18), and of 7 women evaluated 3 days after delivery. All listed hormones except ACTH were measured by RIA (GHRH, CRH and β-endorphin-like immunoreactivity after extraction with silic acid) and ACTH by IRMA. In the late 3rd trimester plasma levels of CRH (P< 0.001), ACTH (P< 0.02), β-endorphin (P< 0.05), cortisol (P< 0.025), as well as GHRH (P< 0.002) and human placental lactogen (hPL) (P< 0.001) were increased in comparison to early 3rd trimester, whereas 3 days after delivery CRH and GHRH became undetectable and those of ACTH and cortisol decreased significantly. The CRH plasma concentrations were found to be strongly correlated with gestational age (r = 0.86, P< 0.001) but not with ACTH and cortisol. GHRH levels correlated mainly with human placental lactogen concentrations (r = 0.64, P< 0.001). Conclusion: In maternal plasma at the 3rd trimester of pregnancy, apart from the known markedly elevated CRH, the GHRH level was also raised. Strong correlations between CRH and gestational age and those between GHRH and human placental lactogen suggest that there is a relationship between these neurohormones and the placental function.