THE EFFECTS OF FORCED WEANING ON THE RESPIRATORY ACTIVITY OF MOUSE MAMMARY GLAND SLICE

Abstract

The effects of forced weaning on the respiratory activity of mammary slices in mice were investigated. The marked fall in oxygen consumption and R. Q. was observed after weaning. The fact that the non-removal of milk from the gland can be a factor responsible for such reduction of activity and further the possibility that the engorgement of milk might systemically inhibit the mammary activity were shown by the experiment using the technique of unilateral ligature of nipples. However, from the result of the renursing experiment, it was discussed that the lactogenic and mammogenic hormone (s) liberated from the anterior pituitary by the suckling stimulus might be effective for the maintenance of respiratory activity of the mammary gland. In conclusion, the removal of milk seems to play as well important role as the suckling stimulus for maintaining the mammary gland in the functional state.