We have investigated the effect of bilateral adrenalectomy at 116–119 days’ gestation on the levels of the messenger (m) RNA for proopiomelanocortin (POMC) in the anterior pituitary of the fetal sheep and in the ovine placentome during late gestation (134–136 days’ gestation). After fetal adrenalectomy there was a significant (p < 0.001) and sustained increase in circulating ACTH concentrations in the adrenalectomised group (1,838 ± 155 ng/l at 130–136 days) when compared with the intact control group (131 ± 25 ng/l at 130–136 days). The mean levels of POMCmRNA relative to 18S RNA were also significantly higher (p < 0.001) in the adrenalectomised fetal sheep pituitaries (2.8 ± 0.12; n = 4) than in the intact/control fetal sheep pituitaries (1.31 ± 0.13; n = 4). In contrast to the findings in the anterior pituitary, POMCmRNA was not detected in RNA extracted from the placentomes of either the adrenalectomised or intact fetal sheep. There was also a significant arteriovenous difference in ACTH concentrations in the umbilical circulation in both adrenalectomised and intact fetal sheep at 134–136 days’ gestation. This study demonstrates therefore that the fetal adrenals act to suppress POMCmRNA levels in late gestation and also that the increase in circulating ACTH after adrenalectomy originates from the pituitary and not the placentome.

To increase purity and potency of the antihemophilic factor (AHF) concentrate prepared by the American Red Cross method, the following modifications were introduced: (1) A cold extraction step was incorporated to remove cold-soluble impurities. The cryoprecipitate (cryo) was extracted with 0.02 M Tris buffer, pH 7.0 (4 ml/g cryo) at 0 degrees C. Factor VIII loss in this step was negligible. (2) AHF was then recovered from the cold-insoluble portion of the cryo by extraction at 21 degrees C with the same buffer. To increase the AHF concentration, this second extraction step was carried out with a smaller buffer volume (2 ml instead of 3--4 ml/g cryo). The subsequent steps, deprothrombinization, filtration and lyophilization were essentially unchanged. To further increase factor VIII concentration, the dried AHF concentrate was reconstituted to 40 rather than 50% of the initial volume. AHF concentrate prepared on a large scale by this method was 20- to 30-fold concentrated and 40- to 50-fold purified over plasma at a recovery of about 250 factor VIII units per liter of plasma. The final product was readily soluble, clear and almost colorless upon reconstitution.