The Action of Hypophysin, Ergamine and Adrenaline upon the Secretion of the Mammary Gland.

THE action of extracts of various organs, especially that of the pituitary gland (hypophysin) upon milk secretion has been frequently investigated. The results of these investigations have been summarised by Hammond [1913], who made an extensive study of the action of hypophysin upon the milk flow in the goat. He found that there was an immediate action and that the effect soon passed off, and he concluded that the action was not upon the muscular tissue of the gland but rather upon the glandular epithelium. The action depended upon the state of nutrition of the animal and upon the stage of lactation. The composition of the milk was not appreciably altered, though that produced by the action of the drug had a higher percentage of fat than other samples. The milk analyses were limited to estimations of fat and total solids and did not extend over long periods. Hammond and Hawk [1917] added some further details respecting the action in different states of nutrition and tested adrenaline, which was found to have no effect. As two goats under normal conditions, on a constant diet, but in different stages of lactation were available, there arose the opportunity of once more testing the action of hypophysin upon the stage of lactation and of extending Hammond's results. Complete analyses of the milk of t-hese goats had been previously made, and by continuing this procedure and including extra samples some further details could be ascertained. At the same time it was of interest to compare its action with that of adrenaline and of ergamine or histamine. The latter substances, as is well known, have an action corresponding with that of excitation of the sympathetic or para-sympathetic nervous systems. Their action, if any, would give probably some information upon the innervation of the mammary gland with nerve fibres of the involuntary nervous system. Hammond's results with hypophysin have been confirmed and extended; ergamine and adrenaline, as might have been expected, had no action.