Changes in the milk composition of nonpuerperal women.

Studies were undertaken to determine the effect of expressing small volumes of breast fluid (less than 3.0 ml) on the progressive changes in concentrations of lactose, proteins, and electrolytes in the mammary secretions of four nonpuerperal women with galactorrhea and two nonpuerperal women who artificially induced lactation by breast hyperstimulation. The changes in the concentration of the milk constituents in the mammary secretion of these women are compared to the levels in colostrum, transitional and mature milk obtained from normal lactationg women. In one woman galactorrhea was associated with hypothyroidism and abnormally elevated blood levels of prolactin and thyroid-stimulating hormone. The breast secretion contained lactose, protein, and alpha-lactalbumin at colostrum-like levels over the entire 53 days of sampling. In two women with galactorrhea and amenorrhea associated with a pituitary tumor and hyperprolactinemia, a colostrum-like secretion was expressed on the first day of sampling but with daily sampling during a period of a month the composition approached that of normal milk. Similar results were obtained in another woman with galactorrhea, which appeared to be induced by a psychotropic drug (haloperidol), when she expressed breast fluid at 2-day intervals over a period of a month. In a second series of samples collected from this woman at intervals of 5 days or more over a period of a month, the concentration of lactose and proteins remained at colostrum levels. The composition of the breast secretion produced by two women who induced lactation artificially by breast hyperstimulation was close to the composition obtained for women during established lactation following normal pregnancy. These findings are discussed in relation to breast function and endocrine disorders.