Although fetal growth is generally considered to be independent of pituitary growth hormone (GH), it is possible that pituitary GH plays a modulatory role in organ development or that a GH-like substance of non pituitary origin may influence fetal growth through the GH receptor. Accordingly, we have used immunohistochemisty, northern blot analysis, the reverse transcriptase-polymerase chain reaction and solution hybridization to study the ontogeny of the GH receptor/binding protein (BP) from the 12-day-old embryo (E12) to the E18 rat fetus
