THE OCCURRENCE OF INSULIN IN THE PANCREAS OF FOETUSES OF SOME RODENTS

Abstract

SUMMARY A study has been made of the occurrence of insulin in the pancreas of the foetuses of some rodents. The histological methods used confirm the findings of earlier investigators that definite β-granulation appears in the rat foetus on the 17th–18th day of gestation and in the rabbit just before or after birth. Insulin in the foetal rat was demonstrated by the fluorescent antibody method from the 14th day onwards. Bioassays of extracts of pancreas of foetuses from normal animals revealed the presence of insulin or an insulin-like substance in the 14-day rat foetus, in the 18- to 19-day rabbit foetus, in the 16-day mouse foetus and in the 11-day hamster foetus. These findings suggest that insulin was present in the foetuses of these rodents before mature β-granulation could be detected microscopically.