Studies on differentiation of Mûllerian ducts in the quail, Coturnix coturnix japonica. II. Effects of sex hormones on nucleic acid synthesis in isolated female ducts.

The present investigations were carried out in an effort to determine the mechanisms underlying differentiation in the avian Müllerian duct, especially the asymmetrical differentiation of the female ducts. Using the isolated female ducts of Japanese quail, the incorporations of 3H-uridine and 14C-thymidine were determined in vitro at several embryonic stages. Incorporation of 3H-uridine was altered with some synchronous fluctuation during the embryonic period in both the left and right ducts, while 14C-thymidine incorporation first decreased rapidly and subsequently, only slightly, during the same period. By administering sex hormones in vitro nucleotide incorporation was affected to an appreciable extent characteristic of the duct at each stage. This hormonal susceptibility was also periodically altered during duct differentiation. The growing left duct continued to receive an apparent stimulation under the hormonal conditions, while the involuting right duct was sometimes inhibited under the same conditions. Such hormonal susceptibilities may explain the asymmetrical differentiation of the female left and right ducts during this embryonic period.