Photoperiod times ontogeny of androgen receptor-immunoreactive cells in ferrets

Regional increases in the density of androgen receptor-immunoreactive (AR-IR) brain cells are temporally correlated with pubertal maturation in male ferrets. If these increases in AR-IR cells are directly linked to pubertal maturation, then experimentally advancing the onset of puberty should similarly advance the timing of the increase in AR-IR cells. Photoinduction of pubertal maturation by transfer to long photoperiods advanced the onset of gonadal growth, elevated testosterone secretion and increased density of AR-IR cells in regions of the hypothalamus, relative to ferrets undergoing spontaneous pubertal maturation under short photoperiods. This experiment provides evidence that an increase in the density of AR-IR cells in specific brain regions is a neuroanatomical correlate of puberty that is also influenced by environmental day length.