Effects of maternal undernutrition during lactation on aromatase, estrogen, and androgen receptors expression in rat testis at weaning.

The goal of this study was to evaluate the effects of maternal malnutrition during lactation on serum levels of testosterone and estradiol, testicular testosterone concentration, aromatase, testicular androgen (AR) and estrogen alpha (ERalpha) receptors expression in the pups at weaning. From parturition until weaning, Wistar rats were separated into three groups: (C) control group, with free access to a standard laboratory diet containing 23% protein; protein-energy restricted (PER) group, with free access to an isoenergy and protein-restricted diet containing 8% protein; and energy-restricted (ER) group, receiving standard laboratory diet in restricted quantities, which were calculated according to the mean ingestion of the PER group. All pups were killed at weaning, corresponding to 21 days post partum. Compared with the C group, body weights (C=48 +/- 2.3 g; PER=20 +/- 1.3 g; ER=25.4 +/- 0.9 g; P<0.01) and testicular weights (C=0.15 +/- 0.02 g, PER=0.05 +/- 0.01 g, ER=0.06 +/- 0.02 g, P < 0.001) of both PER and ER groups were lower. However, there was no significant difference in the testicular/body weight ratio in PER and ER groups compared with the C group. The testosterone serum concentration (ng/ml) was significantly higher in the PER group compared with ER and C groups (C=0.09 +/- 0.012; PER=0.45 +/- 0.04; ER=0.15 +/- 0.03, P < 0.01). Testicular testosterone concentration (C=2.1 +/- 0.43; PER=6.5 +/- 0.7; ER=13 +/- 2.3, P < 0.01) was increased in treated groups when compared with controls. The estradiol serum concentration (pg/ml) was lower in both dietary groups (C=74 +/- 4.6; PER=49 +/- 3.2; ER=60 +/- 5.5, P < 0.01). The amounts of aromatase mRNA and ERalpha transcripts were significantly lower (P<0.05) in PER and ER groups; conversely AR (both mRNA and protein) was significantly enhanced (P<0.05) in treated animals. The nutritional state in early phases of development is important since we have demonstrated here that the maternal malnutrition during lactation leads to alterations in estradiol and testosterone serum concentrations, testicular testosterone concentration, AR and ERalpha expression together with a decrease of aromatase expression. All together, these changes of steroid status may be deleterious for future germ cell development and reproductive function of these male pups submitted to early malnutrition.

Comportamento alimentar de ratos adultos submetidos à restrição protéica cujas mães sofreram desnutrição durante a lactação / Feeding behavior of adult rats submitted to protein malnutrition whose members received protein restricted diets during lactation

Foi avaliado o consumo alimentar de animais adultos submetidos à restrição protéica, cujas mães receberam dieta hipoprotéica ou hipocalórica na lactação: controle (C) ração normal com 23 por cento de proteína; restrição protéica (RP) 8 por cento de proteína; restrição energética (RE) 23 por cento de proteína, em quantidade restrita à ingerida pelo grupo restrição protéica. Após o desmame todos os filhotes receberam ração normal até 60 dias e nesta época foram submetidos, por 21 dias, ao seguinte tratamento: (C/C)-filhotes de mães C recebendo ração normal; (restrição protéica/controle)-filhotes de mães Controle, recebendo ração hipoprotéica; (C/RP)-filhotes de mães RP recebendo ração normal; (RP/RP)-filhotes de mães RP recebendo ração hipoprotéica; (C/RE)-filhotes de mães RE recebendo ração normal; (RP/RE)-filhotes de mães RE recebendo ração hipoprotéica. Os filhotes de mães RP consumiram menos ração até 57 dias (p<0,01), enquanto os filhotes de mães RE normalizaram a ingestão aos 37 dias. Aos 81 dias, os animais submetidos à restrição protéica consumiram menos ração (p<0,01). A dieta materna na lactação modificou o consumo alimentar e o peso corporal da prole na vida adulta, estando, possivelmente, a restrição protéica associada a uma alteração permanente no controle hipotalâmico da seleção de nutrientes da prole