Abstract
We have pointed out that the administration of anterior-pituitary-like hormone (A.P.L.) to the hypophysectomized rat cannot prevent the degenerative changes in the ovary which invariably occur after the removal of the pituitary. 1 We also found that it is impossible to induce maturation of follicles and corpus luteum formation in the hypophysectomized rat with A.P.L. injections. In the absence of the hypophysis, A.P.L. leads only to the luteinization of thecal cells but it does not act upon the ovary as it would under normal conditions. The present experiments show us that it is possible to obtain both follicle maturation and corpus luteum formation in the hypophysectomized rat if certain pituitary extracts are administered simultaneously with A.P.L.
In the first series, 6 rats were hypophysectomized when 22 days old, and from that time they received 0.5 cc. of a 0.5% aqueous ammonia extract (1 cc. = 1/10 gm. of anterior lobe tissue), and 25-50 units of A.P.L. daily for 9 days. They all showed squamous vaginal smears on the fourth to the sixth day, and the histological appearance of their ovaries was the same as that of normal immature females receiving A.P.L. Numerous corpora lutea and mature follicles had been formed in these immature rats in the absence of living pituitary tissue.
In the second series, 7 postpuberal female rats, weighing 72-129 gm., were hypophysectomized and treated with 100 units of A.P.L and 1/4 cc. of the same ammoniacal pituitary extract daily for 14 to 24 days. At autopsy they showed numerous corpora lutea, some of them quite recent (Fig. 1). Their ovaries were enlarged, weighing between 43 and 156 mg. Similar results were also obtained with the combination of A.P.L. and aqueous acetic acid extract of the pituitary.
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