Estimation of free myo-inositol in milks of various species and its source in milk of rats (Rattus norvegicus).

Free myo-inositol content of milk of rats and other rodents fed standard laboratory chow is 80 mg/100 g as compared to about 4 mg/100 g for cow milk. Feeding experiments with graded amounts of myo-inositol demonstrated that the myo-inositol content of milk is strongly influenced by dietary intake. Radioactivity from either [carbon-14] glucose or [hydrogen-3] myo-inositol injected intraperitoneally was incorporated rapidly into milk myo-inositol. Thus, both mammary biosynthesis and active transport contribute to the high myo-inositol in rat milk, but the latter is quantitatively the more important.