Relationship of the Pituitary to the × zone of the Mouse Adrenal. ∗

The relationship of the × zone of the mouse adrenal 1 , 2 , 3 to the pituitary is not known. It was considered that the use of the technic of hypophysectomy might produce results of help in the elucidation of this problem.

Material and Methods. Virgin female “Swiss albino” mice, aged 40-42 days at the commencement of the experiment, were used. The adrenal × zone is well developed at this age. Hypophysectomy was performed by the parapharyngeal approach. Injection of the hormones noted below was started 24 hours after the operation (except that the chorionic gonadotropin injections were commenced 48 hours after operation) and the animals killed 24 hours after the last injection. The mice were grouped as follows:

1. Twelve intact untreated animals killed at 54-58 days of age.

2. Eleven animals hypophysectomised for 12 days and 8 for 14 days and then killed.

3. Nine hypophysectomised animals injected with a pituitary preparation, principally adrenocorticotropin+ in nature, 1 mg per day divided into three intraperitoneal in jections, for 12 days.

4. Nine hypophysectomised animals injected subcutaneously with 1 mg of pituitary gonadotropin, principally LH†† in nature, for 10 days.

5. Five hypophysectomised animals injected subcutaneously with 1 mg per day of pituitary gonadotropin, principally FSH in nature, for 10 days.

6. Six hypophysectomised animals injected intraperitoneally with 11 LU of human chorionic gonadotropin (“Korotrin”) per day for 10 days.

The right adrenal was treated routinely after fixation in Bouin's and stained in Harris' haemotoxylin and eosin or Heidenhain's Azan, The left adrenals were fixed for histochemical studies and are not being reported upon here. The thymus, uterus and ovaries were weighed; the ovaries were then treated as for the right adrenal. The completeness of hypophysectomy was judged by the examination of serial sections of the appropriate area in 2 cases from each group; in the remainder the success of the operation was judged by the examination of the sella turcica region under binoculars (x 15). Added confirmation was given by the weight of the animal and, where relevant, by the weights of the uterus and ovaries and the histological condition of the ovaries and adrenals.