Changes in alkaline phosphatase activity of rat vaginal epithelium during the estrous cycle

Abstract

Increase in alkaline phosphatase activity of vaginal epithelium of the mouse following administration of estrogen to spayed animals has been reported by Jeener ('47) and Kame11 and Atkinson ( '48). The present study represents an attempt to correlate the changes in localization and intensity of phosphatase activity in vaginal epithelium with the structural changes occurring during the growth and regression of this membrane seen in the several stages of the estrous cycle of the normal rat. MATERIAL AND METHODSA large group of albino female rats was examined by daily vaginal smears through 3 or 4 estrous cycles. The smears were obtained by lavage in order to minimize trauma to the vagina. Eighteen animals which had exhibited normal cycles were sacrificed, 5 each in diestrus, proestrus, and estrus and three in metestrus.Five female rats spayed for periods of from 2 to 5 weeks were injected with estradiol benzoate in oil. The total amounts administered over three days ranged from 0.15 to 0.5mg.Five uninjected spayed females served as controls. The spayed animals were killed on the day following the last injection.121

Alkaline Phosphatase Activity in the Vagina of Neonatally Androgenized Adult Rats

“…7,10). The distribution pattern of alkaline phosphatase in this portion of vaginae in these rats was approximately the same as that in the vaginae of non-androgenized, normal female rats at late proestrus to estrus (Ring, 1950). As has already been reported, the proximal vagina is the only portion of the vagina that is capable of reacting to estrogen in neonatally androgenized rats (Takewaki, 1965b(Takewaki, , 1966.…”

“…The outer part of the stroma showed a very slight reaction, if any. The pattern of distribution of alkaline phosphatase in the proximal vagina was approximately similar to that in the normal rat vagina at diestrus (Ring, 1950). Alkaline phosphatase activity was low in the epithelium of the middle vaginae, although a small amount of deposits of cobalt sulfide was found in the middle zone of the stratified epithelium, at least in some rats (Fig.…”

“…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.…”

“…

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.

…”