Stimulation by 17 alpha-hydroxyprogesterone of glycoprotein and glycosaminoglycan synthesis in human placenta in vitro

The incorporation of 14C-glucosamine into glycoproteins (GP) and glycosaminoglycans (GAG), of 3H-leucine into protein, and the hexuronic acid (HA) content of polymerized GAG was determined in incubated placental tissue. In placentae of earlier gestational age (GA), incorporation of 14C-glucosamine was 2.6 times greater than other at 38-39 weeks GA. 19 of 26 placentae at 38-39 weeks GA responded by one or more parameters when incubated with 0.5-3 microM 17 alpha-OH-progesterone (17OHP). Those which did not respond were all of earlier GA; the placental content of GAG decreased in these from 31.1 +/- 1.8 nmol HA/mg protein to 16.4 +/- 1.5 nmol in placentae of GA 38-39 weeks. In the latter, 17OHP increased GAG by 42.5% to 24.4 +/- 2.5 nmol HA/mg protein in a 2-hour incubation. Progesterone, oestriol, cortisol and testosterone were without effect. It is concluded that synthesis of placental GAG decreases toward the end of gestation, but can be increased by 17OHP specifically. This indicates that 17OHP is a biologically active steroid and might have a role in maintaining placental function.