Abstract
Almost all the experimental data on the lactation principle of the anterior pituitary have been obtained from studies involving the use of the rabbit, guinea pig, rat or dove as the test animal. These species do not allow any quantitative estimation of the milk yield, Griiter and Strieker 1 demonstrated that in cows in normal lactation, it was possible through one injection of a potent extract of the anterior lobe to increase the milk yield 1 to 1/2 liters per day. Asdell 2 reports that it was possible to prevent, “for a time at any rate, the normal decline in milk yield with advancing lactation” in the goat, by injections of anterior lobe extract (Parke, Davis & Co.). Using this same extract, Asdell was unable to significantly initiate milk secretion in a young virgin goat, nor was he able to effect any increase in the milk yield of a mature goat whose lactation was nearly spent.
In this laboratory w;e have prepared our own alkaline extracts of the anterior pituitary. Copious lactation has been induced in 3 virgin goats and one dry goat. Figure 1, a and b, illustrates in a striking manner the effect of daily subcutaneous administration of 15 cc. alkaline extract of the anterior pituitary for 6 days. This goat on her first milking gave 4 pounds of milk. Further, it should be emphasized that all attempts to induce secretion of milk from her udder before the injections were started, failed. The same is true of the other 2 virgin goats and the dry goat. After 10 days, the injections were discontinued because it was evident that no further increase in yield could be effected.
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