Postnatal synthesis of fetal and adult hemoglobin was studied with radioactive iron (Fe59) and glycine-2-C14 in newborn goats.
At birth about 60 per cent of Hb-F is present in newborn goats; after 60 days only about 5 per cent is found. Two goats were treated with "exchange transfusions" with blood of the mother. Using an alkali denaturation method the fetal hemoglobin was not demonstrable during the first few days after this treatment, but 20 days later about 20 per cent was present in circulating blood.
Maxima of radioiron-specific activity in adult hemoglobin occurred in untreated newborn goats at the 12th day, of C14 at the sixth day; in "exchange goats" for radioiron at the 8th day. The fetal hemoglobin maxima of specific activity occurred in the untreated goats resp. after 32 and 24 days, in "exchange goats" after 8 days.
The reappearance of Hb-F in "exchange goats" and the specific activity of Hb-F are direct indications for a synthesis of this component after birth in this species.