Abstract
In order to clarify whether the administration of oxytocin after weaning could prevent a decline in the metabolic activities of the mammary glands of rats, the following experiments were carried out.
The measurement of the respiration (R. Q. & -Qo2) and the production of lactic acid was employed to evaluate the metabolic activities of the mammary glands, and the morphological changes were also observed in the histological preparations to check the degree of involution.
The involution of the mammary glands after weaning was retarded by the administration of oxytocin to the mother rat during the experimental period. This finding was consistent with that of Benson and Folley (1957a, b).
However, the administration of oxytocin failed to prevent a steep decrease in the R. Q. and an increase in Q (lactic acid) which followed weaning. Although the lobule-alveolar system was maintained rather well in the mammary glands of rats receiving prolactin, a decrease in the R. Q. was also observed.
