The influence of the intra-intestinal administration of magnesium sulphate on the production of hyaline casts in dogs

Following our study of hyaline cast production after the intramuscular or intravenous injection of hydrated magnesium sulphate and certain other salts, reported to this society in February and June of this year, 1 Dr. Meltzer suggested that the investigation be carried further by a series of experiments in which the MgSO₄ was given directly into the intestines, simulating its use as a purgative.

The typical procedure in the present series was to inject an m/1 solution of hydrated MgSO₄, in doses of .18 or .2 gm. per kilo. body weight, through a glass cannula into the upper duodenum. The small intestine was isolated by ligatures just below the pylorus and at the ileo-cecal valve. The operation was performed under complete ether anesthesia and the dogs were killed at the end of five or six hours. For two animals the solution was diluted to m/3 before injection and in three other cases the ligature was not placed at the ileo-cecal valve. In each case control urines were examined for casts and albumin.

Of twelve dogs in this series ten showed hyaline casts after the magnesium injection; in eight the casts were abundant. They were usually accompanied by a trace of albumin. The casts were most numerous in the two to three hour period, but usually persisted in small numbers until the end of the experiment. Gross examination of the kidneys revealed no significant changes.

The general effects of the absorbed magnesium appeared in dullness and relaxation, partial or complete anesthesia and paralysis, and in one case in a typical “magnesium death” from respiratory paralysis.