Effects of maternal undernutrition during lactation on estrogen and androgen receptor expressions in rat ovary at puberty

Abstract 

Objective

The aim of this study was to evaluate the effects of maternal protein and energy-restricted diets during lactation in folliculogenesis and its relations to androgen and estrogen receptors in the offspring at puberty.

Methods

At parturition, dams were randomly assigned to a control (C) group, with free access to a standard laboratory diet containing 23% protein; a protein–energy-restricted (PER) group, with free access to an iso-energy and protein-restricted diet containing 8% protein; and an energy-restricted (ER) group, receiving standard laboratory diet in restricted quantities. After weaning, female pups had free access to standard laboratory diet.

Results

The number of preantral (C 13.72 ± 2.87, PER 26.36 ± 3.03, ER 26.88 ± 2.31, P < 0.05) and small antral (C 9.32 ± 1.32, PER 17.64 ± 2.33, ER 17.04 ± 2.22, P < 0.05) follicles was significantly increased by maternal malnutrition. The number of primordial follicles (C 10.57 ± 1.61, PER 4.30 ± 0.62, ER 6.28 ± 1.30, P < 0.05), Graafian follicles (C 1.04 ± 0.09, PER 0.52 ± 0.10, ER 0.36 ± 0.11, P < 0.01), and corpus luteum (C 4.84 ± 0.62, PER 2.80 ± 0.50, ER 3.24 ± 0.27, P < 0.05) was significantly reduced. Maternal protein- and energy-restricted diets led to a significant decrease in the androgen (C 9815 ± 1015, PER 6071 ± 838.7, ER 5811 ± 699.3, P < 0.05) and estrogen (C 0.79 ± 0.244, PER 0.12 ± 0.035, ER 0.20 ± 0.036, P < 0.05) α-receptors. In growing follicles, androgen receptor was immuno-expressed in granulosa and theca cells. Estrogen receptor-α was mainly expressed in stroma cells.

Conclusion

Our results suggest that maternal protein- and energy-restricted diets during lactation can disturb the follicular development of the offspring, probably by reducing the number of androgen and estrogen receptors in the ovary.

Keywords: Nutrition disorders, Lactation, Folliculogenesis, Follicles, Estrogen and estrogen receptor-α