There are observations on record which indicate that the secretion of
milk may be influenced by a contemporaneous diuresis. Precisely what
changes in the composition of the milk may be initiated in this way had
not been determined until recently, when the question of the influence
of specific diuretics on milk flow was investigated by Steenbock at the
University of Wisconsin. He remarks that in view of the importance which
heretofore unknown constituents of diets and rations have lately
assumed, it is of the greatest interest to dissect the various factors
normally operative in the body under ordinary conditions of diet.
Steenbock found that urea, for example, administered in a diuretic dose,
is able to decrease temporarily the flow of milk. On repeated
administration, however, the increased intake of water which follows the
impoverishment of the tissues with respect to water content balances the
draft for water imposed by the diuretic, and the milk secretion comes
back to normal. Other diuretic salts, like sodium chloride, may be
entirely unable to depress the milk secretion under normal
circumstances, because they call forth a compensating thirst which
simultaneously increases the water intake. In cases in which diuresis
does lead to temporarily decreased flow of milk, the percentage of
solids in the secretion is ordinarily increased, the fat being the
principal variable. In ordinary experience, however, the composition of
the milk may be regarded as essentially unaltered by slight variations
in renal activity.—_The Journal of the American Med. Asso._