THE DISTRIBUTION OF CELL TYPES IN THE ANTERIOR HYPOPHYSIS DURING LATE PREGNANCY AND LACTATION

Abstract
Differential cell counts of the hypophysis from pregnant and lactating rats show that at 3-days post-partum the acidophiles have increased by almost 100% above the number present in pregnant animals. This number decreases as lactation continues but does not revert to the pregnancy level. The increased number of acidophiles and their increased granulation is believed to be associated with the high lactogen content of the hypophysis. This increase of acidophiles was due to conversion of chromophobes and not from division of acidophiles. Basophiles are more numerous in 10-day pregnant rats than at 20-days pregnant or during lactation. There is no significant wt. change in the rat hypophysis during lactation as compared with pregnancy.