Maternal treatment with dexamethasone during lactation delays male puberty and disrupts reproductive functions via hypothalamic-pituitary-gonadal axis alterations.

The effects of maternal treatment with dexamethasone during lactation on pubertal timing, serum hormonal profile and sperm indices in the male offspring were assessed. Twenty lactating dams were divided into 4 groups (n=5). Group 1 was administered subcutaneously 0.02ml/100g/day normal saline at lactation days 1-21. Groups 2-4 were administered subcutaneously 100μg/kg/day dexamethasone (Dex) at lactation days 1-7, 1-14, and 1-21 respectively. Results showed that there was significant reduction in serum testosterone in the DexLD 1-7 (p<0.05), DexLD 1-14 (p<0.01) and DexLD 1-21 (p<0.001) relative to control. In addition there was a significant reduction in serum FSH and LH in the DexLD 1-7 (p<0.01), DexLD 1-14 (p<0.001) and DexLD 1-21 (p<0.001) when compared with the control. Treatment with dexamethasone during lactation significantly increased the days of preputial separation in the DexLD 1-7 (p<0.05), DexLD 1-14 (p<0.05) and DexLD 1-21 (p<0.001) relative to control. Maternal treatment with dexamethasone throughout lactation period also significantly reduced sperm counts (p<0.001), motility (p<0.01) and increased percentage abnormal sperm (p<0.001) in the offspring when compared with the control. In conclusion, maternal treatment with dexamethasone during lactation may induce delayed puberty and disrupt reproductive functions by altering activities at hypothalamic-pituitary-gonadal axis in the male offspring.