COLLAGEN FORMATION AND CHANGES IN CELL POPULATION IN RATS UTERUS AFTER DISTENSION WITH WAX

Injection, through the cervical canal, of wax into the lumen of the uterine horn of spayed rats treated with a mixture of ostradiol‐17β, progesterone and relaxin, produced an increase in the total collagen content of the horn (estimated by determination of hydroxyproline). This occurred as a later phenomenon in a general growth process, accompanied by increase in the weight of the horn and cell division. Counts of the proportion of nuclei in mitosis after a single injection of wax showed increase within 24 hr., subsiding in 4 days. Estimates of total numbers of nuclei in the horn were also made in sections of fixed material from undistended and distended horns 4 days after a single injection of wax. Significant increase was found in epithelial and connective tissue cells of the endometrium and in muscle cells. The following estimates (in millions) were obtained for nuclear populations of undistended horns; luminal epithelium, 6; glandular epithelium, 2·5; endometrial connective tissue, 39; other connective tissue, 100; circuilar muscle, 34; longitudinal muscle, 29; granulocytes, 5. © 1968 The Physiological Society