On the basis of the chick units of hormone per gm. of fresh pituitary, a gradual rise was observed in hormone cone, reaching a maximum in the 1500 gm. group in [female][female] and between 2000 and 2500 gms. in [male] New Zealand white rabbits. The [female] AP especially showed a rather uniform hormone cone, throughout reproductive life except for a notable decrease in the heaviest wt. class. This decrease is interpreted as an indication of the climacteric. The gonadotrophic hormone cone, of the sexually mature [male][male] averaged about 70% above that of the comparable [female][female].