Steroid hormone and antihormone induced changes in the pineal and adrenocortical karyomorphology and cell proliferation in mice ( Mus musculus )

Hormone-induced reponsiveness of the pineal and adrenal glands was studied in post-pubertal male mice (Mus musculus). The influence of steroid hormones (estradiol and testosterone) and non-steroidal antihormones (tamoxifen and flutamide) on pineal and adrenal karyomorphology and cell proliferation activity was analyzed. Estradiol was injected at a dose of 5µg, testosterone 100µg, tamoxifen 500µg and flutamide 2mg per 100g body weight administered intramuscularly in all cases for ten consecutive days. Control mice were similarly injected with 0.3ml of peanut oil vehicle intramuscularly for the same duration. The results indicated that, except testosterone, all other treatments with estradiol, tamoxifen and flutamide caused significant hyperactivity in both the pineal and the adrenal glands, associated with significantly increased cell proliferation activity. On the contrary, testosterone administration was inhibitory to pineal - adrenal karyometric and mitotic incidence values. It was concluded that in male post-pubertal mice both pineal and adrenal glands show antagonistic response towards estradiol and testosterone administration. Although tamoxifen showed estrogen agonistic behaviour, flutamide conversely induced pineal and adrenal cytophysiological stimulation. Such stimulatory response was antagonistic to the inhibitory response shown by pineal and adrenal karyomorphology and cell proliferation following testosterone administration.