Serum estrogen concentrations during postnatal development in male pigs

Serum concentrations of estrone (E1), estradiol (E2), estrone sulfate (E1S), and testosterone (T) were quantified in male pigs at 10 ages from 2 weeks to 2 years. Changes in the concentrations of all four of these hormones were characterized by elevated amounts during neonatal development (1 to 3 weeks of age), a nadir for concentration of each hormone between 1 and 3 months of age, an increase during pubertal development with maximal concentrations at 8 months of age, and no further change by 2 years of age. E1S was predominant of the three estrogens at all age groups with mean concentrations that ranged from 2 to 33 ng/ml. E1 was present in higher concentrations during neonatal development than E2, whereas the reverse situation was observed after 4 months of age. Observations from the present study indicate that early neonatal and pubertal development in male pigs are associated with elevated serum estrogen concentrations.