Regulation of food consumption during pregnancy and lactation in mice.

The aim of the present work was to assess the expression of agouti-like protein and neuropeptide Y in pregnant and lactating mice and to compare this with the leptin level and food consumption. Food consumption, blood leptin levels, and agouti-like protein and neuropeptide Y mRNA levels in the hypothalamus of C57Bl/6J mice were assessed on days 7, 13, and 18 of pregnancy and on days 10 and 21 of lactation, and in virgin females of the same ages. During pregnancy, food consumption and leptin levels decreased on day 7 and increased in day 18 of pregnancy, while neuropeptide Y mRNA levels increased on day 13 and then remained unaltered, and the agouti-like protein level increased on day 18. After parturition, food consumption continued to increase, while leptin levels and neuropeptide Y mRNA levels decreased to normal. Thus, hyperphagia in pregnancy was due to sequential activation of the expression of neuropeptide Y and agouti-like protein, while in lactation hyperphagia resulted from mechanisms not associated with changes in the expression of these neuropeptides.