Long-Term Effects of Malnutrition During Lactation on the Thyroid Function of Offspring

Abstract

Some studies have shown that the mother's nutritional condition may influence offspring's endocrine function through metabolic imprinting. Recently, we showed that the kind of maternal malnutrition during lactation affects adult body weight of the offspring and it is related to milk composition. We studied lactating rats fed an 8 % protein-restricted diet (PR), a control 23 % protein diet (C), and an energy-restricted diet group (ER). After weaning, all animals received a normal diet until they were 180 days of age. At this time, the animals received a single i. p. injection of ¹³¹I and were sacrificed 2 h after the injection. Total triiodothyronine (TT₃) and total thyroxin (TT₄) serum concentrations were measured by enzyme immunoassay. The PR group had significantly a higher thyroid ¹³¹I uptake, TT₃ serum concentration and in TT₄ serum concentration, compared to the controls. The ER group had only significantly higher TT₃ serum concentration. These results showed that thyroid function regulation in adulthood may depend on maternal nutritional condition during lactation. Probably, PR group had a high thyroid function, whereas the ER group only had an increase in the deiodination of T_4. The hyperthyroidism in the PR group could explain the low body weight observed in those animals.

Key words

Protein - Energy - Malnutrition - Thyroid - Lactation

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