Fluorescent microscopic study of epithalon binding in maternal and fetal rabbit tissues in health and under conditions of placental insufficiency.

Epithalon (regulatory tetrapeptide) labeled with dansil (fluorescent stain) easily penetrates into all tissues and organs of pregnant rabbit females and through the placenta into fetal organs. Incorporation of labeled epithalon in placental tissues is more often observed in fetuses developing under conditions of placental insufficiency than in normal fetuses.