ALTERATION IN THE OESTROUS CYCLE LENGTH AFTER PITUITARY HOMOTRANSPLANTATION IN THE GUINEA-PIG

Abstract

SUMMARY Pituitaries from adult or young guinea-pigs were implanted under the kidney capsule of intact adult female guinea-pigs between the 3rd and 5th days of the oestrous cycle. The oestrous cycles in the recipients of adult pituitaries were mostly normal in length. Seven out of nine animals engrafted with pituitaries from their own litters had a prolonged dioestrus, ranging from 8 to 16 days longer than normal, at the end of which oestrus and ovulation occurred. When the grafts contained pituitaries from one male and one female pup the cycle extension was more pronounced than when they were composed of pituitaries from two or three female pups. The occurrence of prolonged dioestrus accompanied by a delayed ovulation in the graft-bearing animals is suggested to be associated with the production of luteotrophic hormone by the graft tissue, possibly deriving from basophil cells.