Alkaline Phosphatase Activity in the Vagina of Neonatally Androgenized Adult Rats

Abstract

In the vagina of adult rats given subcutaneous injections of large doses of testosterone propionate for periods of varying lengths from the day of birth, three portions can be distinguished by the state of the epithelium, i.e, the proximal vagina lined with an epithelium consisting of two to several layers of cells, the middle vagina bearing a stratified non-squamous epithelium, and the distal vagina having a squamous cornified epithelium.Of the three portions, only the epithelium lining the proximal vagina is capable of reacting to estrogen by cornification and to estrogen plus progesterone by mucification, the middle and distal portions of the vagina being unmodified by ovarian steroids (Takewaki, 1965a(Takewaki, , b, 1966.Histochemical studies carried out by previous workers (Ring, 1950;Ford, 1956) have revealed that in normal rats alkaline phosphatase activity in the vaginal epithelium is highest in layers of cells undergoing keratinization and accordingly the enzyme active zone gradually shifts toward the surface of the epithelium as keratinization progresses. On the other hand, Dux (1960) reported that in the epithelium of mouse vaginal tumors exhibiting estrogen-independent cornification, alkaline phosphatase activity was not enhanced by estrogen, unlike in the epithelium of normal mouse vaginae.It was thought interesting, therefore, to study the distribution of alkaline phosphatase activity in the three portions of vaginae of neonatally androgenized rats, especially in the estrogen-reactive proximal portion and the estrogen-unresponsive distal portion.Materials and Methods. Female rats belonging to 3 litters of the T strain from the colony maintained in this laboratory were used in these studies. The rats were given subcutaneous injections of testosterone propionate for 15 days from the day of birth, 0.5 mg in 0.02 ml of sesame oil for the first 10 days and 1.0 mg in 0.04 ml of oil from the 11th day on, when the rats became adult, they were so divided into 3 groups that at least one rat from each litter was contained in each group.In Group 1, 5 androgenized rats were not subjected to any