Negative calcium balance during lactation in rural Mexican women.

Background: Additional calcium is required during lactation, and several calcium regulatory factors are involved in calcium balance. In lactating rural women who have marginal nutrition and consume a high-fiber diet, negative calcium balance may be expected.

Objective: We evaluated calcium balance and its association with potential calcium regulatory factors in lactating, rural Mexican women who had marginal nutrition and consumed a high-fiber diet.

Induction of expression of branched-chain aminotransferase and alpha-keto acid dehydrogenase in rat tissues during lactation.

This study was designed to determine the effect of lactation and weaning on the gene expression of branched-chain aminotransaminase (BCAT) and branched-chain alpha-keto acid dehydrogenase (BCKD) in different tissues of the lactating rat. BCAT activity increased in mammary tissue during lactation and was 6-fold higher than in virgin rats. This increase was associated with an increase in protein levels measured by immunoblot analysis, and with an increase in BCAT mitochondrial (BCATm) mRNA concentration.

Negative balance of calcium during lactation in marginally nourished women.

Thirty-three rural Mexican women (age, 18-36y; weight, 50.3+/-3 kg; height, 148.3+/-2 cm) were studied under metabolic balance conditions.

Amino acid intake during lactation and amino acids of plasma and human milk.

The aim of this study was to determine the free amino acid pool in plasma and milk in marginally nourished lactating women. Twenty-eight rural women (age, 23.9+/-5y; weight 50.

Localization and expression of BCAT during pregnancy and lactation in the rat mammary gland.

During lactation, branched-chain aminotransferase (BCAT) gene expression increases in the mammary gland. To determine the cell type and whether this induction is present only during lactation, female rats were randomly assigned to one of three experimental groups: pregnancy, lactation, or postweaning. Mammary gland BCAT activity during the first days of pregnancy was similar to that of virgin rats, increasing significantly from day 16 to the last day of pregnancy.