Abstract
SUMMARY: ACTH was administered to pregnant rabbits in doses of 5, 3 and 1·5mg twice daily from the 19th to 26th day of pregnancy. Cortisone 4 mg/kg daily was given to rabbits from the 20th to 27th day of pregnancy. The maternal administration of ACTH (except in the lowest doses) was associated with a high foetal mortality, and few of the liveborn rabbitssurvived. Cortisone produced a similar mortality and a marked depression of birth weight. Sections of the pancreas of foetal rabbits showed early maturation and associated degeneration of the islet tissue. The changes after the administration of cortisone were more marked than those following ACTH. ACTH 0·4 mg twice daily, or cortisone 1 mg daily, was given to rats from the 13th to 20th day of pregnancy. Little effect on foetal mortality or average foetal weight was observed, but there was a marked variation in the weight of rats in the same litter in the cortisone-treated group. Some reduction in the amount of islet tissue at birth was seen, but premature maturation was only seen in one 19-day foetus. An attempt has been made to relate the changes produced in the foetal pancreas by the maternal administration of ACTH and cortisone to those seen in the foetus of the diabetic mother.