COMPARATIVE ICSH-ESTIMATIONS IN THE SERUM OF GONADECTOMIZED MALE AND FEMALE RATS WITH A TRANSPLANTED OVARY
ABSTRACT In adult female rats an ICSH-peak in the serum was found in the afternoon of pro-oestrus (preliminary experiments). ICSH was determined by the ventral prostate assay. Comparative ICSH-determinations were carried out in the serum of adult gonadectomized male and female rats with an ovarian transplant. Gonadectomy and transplantation of an ovary into the right hind-leg had been carried out two months previously. Irrespective as to whether there were corpora lutea in the transplants of castrated males, the ICSH-level in the serum of the males did not differ from the base level in the serum of the females. The ICSH-peak in the serum of the females (afternoon of pro-oestrus) exceeded this level. The relation between the ICSH-peak in the serum and ovulation was demonstrated by the fact that there was no ICSH-peak on the day of prooestrus in spayed females with an ovarian transplant, which in previous cycles had passed through a two days' oestrus. It is suggested that the difference in behaviour between ovarian transplants in spayed females and castrated males might be an expression of the same sex difference as that which appears in response to a single high dose of oestrogen.