CARTILAGE GROWTH AND DIFFERENTIATION IN YOUNG FOWL AS INFLUENCED BY ETHINYL-OESTRADIOL

Abstract

Olive oil (in doses of 0.1-0.25 ml./day given intramusc. for 9 days) and ethinyl-estradiol (in total doses of 70-700 [mu]g. for 8-9 days) have no effect on the increase in body wt. of young fowl 1-19 days old. Ethinyl-estradiol decreases the zones of proliferation and of differentiation of cartilage in the long bones of the hind extremities. This was observed with 450 [mu]g. for 9 days in 19 day-old animals and with 700 [mu]g. for 8 days in 11-day old chicks. With a total dose of 700 [mu]g. for 8 days the adrenocortical tissue is slightly but significantly increased, but 450 [mu]g. for 9 days had no effect whatsoever in this respect. Apparently the cortical steroids do not interfere with the action of estrogens on growing and differentiating cartilage. As was to be expected, the oviducts react to estrogen with rapid growth. At the dose levels used, no wt. changes or gross histo-logical alterations were observed in the thymus.