322 Mammary Growth After Hypophysectomy 



promoting factor. Rather, it has seemed important to determine the hormonal 

 factors necessary to build as complete a mammary tree as is found in the ante- 

 partum rat (LA-f++ or +-f++)- 



Experiments and Results (Table i) 



Experiment i. — Purified lactogenic hormone (2 mg. or 60 I.U. daily) was injected siibcu- 

 taneously for 10 days into 3 normal female rats. The estrous cycles were inhibited, and at 

 necropsy on day 11 the vaginae showed mucification, a single crop of large corpora lutea 

 and small Graafian follicles were found in the ovaries, and the mammary glands showed 

 complete lobulo-alveolar growth (pi. 1, fig. 5). Normal control rats sacrificed at 70 days of age 

 showed a DAB condition in the mammary glands comparable to plate 1, figure 2. 



Experiment 2. — Estrone alone (10 I.U. and 100 I.U. daily), estrone (10 I.U. and 100 I.U.) 

 plus 1 I.U. of progesterone daily, and progesterone alone (1.0 I.U. daily) were injected for 10 

 days into groups of 3 hvpophysectomized female rats. Except for the group injected with pro- 

 gesterone alone, the rats showed estrous vaginae, but the mammary glands in every case 

 showed regressive changes similar to those of hypophysectomized controls (pi. 1, fig. 1). All ol 

 the rats lost ^veight. 



Experiment j. — A preparation of partially purified pituitary follicle-stimulating hormone 

 (FSH) was injected subcutaneously into 3 rats at a daily dose of 5 R.U. for 10 days. This dose 

 produced large follicles in the ovaries and kept the rats in estrus, but as with estrone the mam- 

 mary glands sho^ved regression. The animals lost weight. 



Experiment 4. — Purified sheep lactogenic hormone ^vas injected at the 2 mg. (60 I.U.) level 

 for 10 days into 5 hypophysectomized female rats and purified beef lactogenic hormone at the 



4 mg. level (120 I.U.) for a similar period into 3 hypophysectomized rats. The mammary 

 glands of all but one of these rats showed maintenance (DAB, pi. 1, fig. 2). One animal on the 

 2-mg. dose shoued regressing glands. On an average the rats maintained their preoperative 

 ^veight in this experiment. 



Experiment 5. — Five hypophysectomized female rats were injected daily for 10 days with 

 the same beef lactogenic hormone used in Experiment 4 (2 mg.) plus 10 I.U. estrone. Slight 

 but definite lobulo-alveolar growth (LA-I-, pi. 1, fig. 3) was found in the mammary glands of all 

 but one rat which showed regressive glands. This rat lost 10 gm., although the group showed a 

 slight average gain. 



Experiment 6. — Three hypophysectomized female rats were injected daily for 10 days with 

 2 mg. of the same pine beef lactogenic hormone plus 5 R.U. of FSH. The mammary glands 

 of all animals showed slight lobulo-alveolar giowth (LA-I-, pi. 1, fig. 3). There was an average 

 weight loss of 14 gm. in this group. 



Experiment 7. — Two groups of 3 hypophysectomized female rats were injected daily for 10 

 days with 5 and 10 mg. respectively of a crude lactogenic preparation containing approxi- 

 mately 10 I.U. of lactogenic hormone per mg., a Moon unit (normal immature male rat test) of 

 adrenotrophin in about 60 mg. and a unit of .somatotrophin ("growth hormone") in about 

 1 mg. Slight lobulo-alveolar growth (LA-h) was observed in the mammary glands of five rats 

 while the sixth animal (5-mg. dose) showed DAB. 



Experiment S. — Six hypoph)sectomized female rats were injected daily for 10 days ^vith 

 10 I.U. of estrone plus 5 mg. of crude lactogenic hormone. Excellent lobulo-alveolar growth 

 (LA-H-f, fig. 5) was observed in 5 animals and good growth (LA-l-f, pi. 1, fig. 4) in the sixth. 

 The rats showed an average gain of 2 gm. per day. Other experiments in ^vhich 1.2 and 2.5 mg. 

 of the crude lactogenic extract were injected with 10 I.U. of estrone merely resulted in mam- 

 mary gland maintenance (DAB) although the rats gained from 1 to 2 gm. per day in body 

 weight. 



Experiment §>. — Three hypophysectomized female rats were injected daily for 10 days Avith 



5 mg. of the same crude lactogenic preparation plus 5 R.U. of FSH. The results were similar to 



