Serotonin and dopamine in the hypothalamus of control and malnourished mother rats during pregnancy and lactation and body composition of their offspring.

Objective: To determine concentrations of serotonin and dopamine in the hypothalamus of undernourished rats and controls during pregnancy and lactation and body composition of their offspring.

Methods: Malnourished rats along with control rats were used during pregnancy and lactation. At birth of their offspring, control mothers nursed their young and malnourished rats and the undernourished mothers nursed their offspring and control pups. On days 5, 10, 15, and 21 of lactation (at the beginning and end of a feeding), L-tryptophan (L-Trp)-free, bound and total, plasma prolactin (PRL) and milk composition were determined. Serotonin and dopamine were measured in the hypothalamus. Body composition of offspring was determined.

Results: Increase of free L-Trp was confirmed in undernourished mothers. Furthermore, hypothalamic serotonin was elevated at the start of suckling and decreased at termination. There was also a decrease in dopamine in the hypothalamus at the beginning and end of suckling followed by an increase of plasma PRL that was greater in control mothers who breastfed malnourished offspring. Interestingly, undernourished offspring consumed more milk and showed a clear recovery of body composition with accumulation of body fat.

Discussion: Changes observed in hypothalamic neurotransmitters appear to be closely related to nutritional status and to the response and control of PRL production, possibly to adapt the offspring to the metabolic changes. It was also confirmed that on-demand feeding of undernourished offspring is the main factor involved in nutritional recovery and a predisposition to overweight in the recovered undernourished animals.