Altered Sensitivity of Uterus to Progesterone-Estradiol in Rats Treated Neonatally with Androgen and Ovariectomized as Adults

Abstract

SynopsisFemale rats were made persistent-estrous and anovulatory by giving a single injection of 1.25 mg of testosterone propionate 4 days after birth. The rats were ovariectomized when adult and given 7 daily injections of progesterone plus estradiol in amounts sufadministration of the hormones was commenced on the day following ovariectomy, or 32 or 62 postoperative days after priming with estradiol for 2 days. Incidence of deciduomata following uterine traumatization on the 4th day of the injection period was always much higher in non-androgenized controls than in androgen-sterilized rats. It seems likely that neonatal androgenization results in a permanent or at least a long-lasting reduction of uterine sensitivity to progesterone-estradiol. The longer the interval between ovariectomy and the beginning of progesterone-estradiol administration, the less marked was the mucification of the vaginal epithelium. There was no correlation between the degree of vaginal mucification and the development of deciduomata.

Ultrastructure of the uterine epithelium of mice treated neonatally with estrogen

“…Following combined injections of progesterone and 17/?-estradiol after ovariectomy, incidence of deciduomata in response to uterine trauma is definitely lowered in steroid-treated rats as compared with that in the non-treated control animals similarly treated [Takewaki and Ohta, 1974;Olua and Takewaki, 1976], To obtain the greatest effect of neonatal administration of estrogen on the uterine epithelium, the dose of estrogen and the time of autopsy in the present experiments were determined on the basis of previous findings [Mori, 1975], The apical surface of the uterine epithelial cells of ovariectomized mice under goes some marked changes in response to estrogen. When exposed to estrogen, micro villi increase in length and the surface takes a fuzzy appearance.…”

Restoration of Cyclic Locomotor Activity by Progesterone in Neonatally Estrogenized Persistent-estrous Rats

“…Progesterone appears to antagon- ize the effects of estrogen in this respect (Wade and Zucker, 1969). It seems likely that these steroids act directly on diencephalic neural structures, since the spontaneous activity is reduced by placement of electrolytic lesions in the ventromedial nucleus or in the suprachiasmatic and preoptic regions (Kennedy and Mitra, 1963 a, b ;Kennedy, 1964) .…”

“…It is well known that progesterone stimulates the gonadotropin secretion from the hypophysis and induces luteinization in otherwise polyf ollicular ovaries lacking corpora lutea in female rats exhibiting spontaneous persistent estrus (Everett, 1940) , persistent-estrous rats secured by neonatal steroid treatment (estrogen : Takasugi, 1956(estrogen : Takasugi, , 1965androgen ;Gorski and Barraclough, 1962 ;Barraclough et al, 1964) and castrated male rats bearing subcutaneous ovarian grafts (Takewaki, 1956;Machida, 1968).…”