Localization of 3H-estradiol in the reproductive organs of male and female baboons

Steroid receptor expression in the developing copulatory system of the green anole lizard (Anolis carolinensis)

In adulthood, the copulatory system in male green anole lizards is characterized by the presence of two hemipenes, each controlled by ipsilateral muscles. These structures are present in both sexes early in development, but prior to hatching regress completely in females. Embryonic treatment with steroid hormones alters the morphology of the copulatory system, suggesting active roles for both androgens and estrogens in sexual differentiation. To elucidate the timing and sites of steroid hormone action in the embryonic copulatory system, the distributions of androgen receptor (AR) and estrogen receptor-alpha (ER alpha) mRNA expression were examined. In situ hybridization was conducted on the rostral tail of anoles at three stages spanning differentiation of the copulatory structures: embryonic days (E) 13, 18, and 24 (hatching occurs at approximately E34). At E13, males expressed significantly higher levels of AR mRNA in both hemipenes and muscles than did females, while females at the same age tended to express higher levels of ER alpha mRNA in these structures. By E18, hemipenes and copulatory muscles were regressed in most females, and were not present in any females at E24. In males, no effect of age was detected on the expression of either AR or ER alpha. These data suggest that peripheral copulatory structures in the embryonic anole are direct targets for the actions of both androgens and estrogens in sexual differentiation, consistent with the idea that estradiol facilitates regression in females and androgen promotes survival in males. However, the issue of whether or not a critical period exists remains open.

Role of stroma in carcinogenesis of the prostate

Prostatic development is induced by androgens acting via mesenchymal-epithelial interactions. Androgens elicit their morphogenetic effects by acting through androgen receptors (ARs) in urogenital sinus mesenchyme (UGM), which induces prostatic epithelial development. In adulthood reciprocal homeostatic stromal-epithelial interactions maintain functional differentiation and growth-quiescence. Testosterone plus estradiol (T+E2) have been shown to induce prostatic carcinogenesis in animal models. Thus, tissue recombinant studies were undertaken to explore the mechanisms of prostatic carcinogenesis in BPH-1 cells in which ARs and estrogen receptors (ERs) are undetectable. For this purpose, BPH-1 cells were combined with UGM, and the UGM+BPH-1 recombinants were grafted to adult male hosts. Solid branched epithelial cords and ductal structures formed in untreated UGM+BPH-1 recombinants. Growth was modest, and tumors did not develop. UGM+BPH-1 recombinants treated with T+E2 formed invasive carcinomas. BPH-1 cells lack ARs and ERs, whereas rat UGM expresses both of these receptors. These data show that immortalized nontumorigenic human prostatic epithelial cells can undergo hormonal carcinogenesis in response to T+E2 stimulation via paracrine mechanisms and demonstrate that the stromal environment plays an important role in mediating hormonal carcinogenesis. During prostatic carcinogenesis the stroma undergoes progressive loss of smooth muscle with the appearance of carcinoma-associated fibroblasts (CAF). This altered stroma was tested for its ability to promote carcinogenesis of nontumorigenic but immortalized human prostatic epithelial cells (BPH-1). CAF+BPH-1 tissue recombinants formed large carcinomas. In contrast, recombinants composed of normal prostatic stroma+BPH-1 cells exhibited minimal growth. This stroma-induced malignant transformation was associated with additional genetic alterations and changes in gene expression. Thus, alteration in the stromal microenvironment was sufficient to promote malignant transformation of human prostatic epithelial cells.

Localization and regulation of estrogen, progestin and androgen receptors in the seminal vesicle of the rhesus monkey

We have used monoclonal antibodies against the estrogen (E), progestin (P) and androgen (A) receptors (R) to study receptor localization and regulation in the seminal vesicles of rhesus monkeys under different hormonal conditions. The antibodies caused substantial shifts of the appropriately labeled receptors on sucrose gradients. ER levels were lower in intact males than in immature, castrate, and estrogen-treated castrates. With immunocytochemistry, ER were detectable only in stromal and smooth muscle cells, not the epithelium. The number of ER-positive stromal cells was significantly lower in intact males than in immature, castrate, and estrogen-treated castrates, and low in a DHT-treated castrate animal. Androgen receptors were localized in epithelial as well as stromal and smooth muscle cells, and the number of AR-positive stromal cells was highest in intact adults and lowest in castrated and immature animals. Estrogen treatment at the time of castration induced PR in the ER-positive stromal cells, prevented a decline in the number of AR-positive stromal cells, and caused stromal hypertrophy. In summary, in the seminal vesicle, as in the prostate, ER is restricted to the fibromuscular stroma, is suppressed by androgens, and can mediate induction of PR on estrogen treatment. Androgen receptors are present in epithelial as well as stromal and smooth muscle cells, but variations in hormonal state appear to affect regulation of AR more in the stroma than the epithelium.

Sex steroid receptors in the stomach, liver, pancreas, and gastrointestinal tract of the baboon

Sex steroids have been shown to have a marked effect on the physiologic activities of the liver and the gastrointestinal tract. We performed autoradiographic studies using [3H]estradiol and [3H]dihydrotestosterone on male and female baboons for the purpose of identifying estrogen or androgen receptors, or both, in the liver, pancreas, stomach, and small and large intestines of baboons. Evidence for the presence of estrogen and androgen receptors was made apparent by high concentrations of silver grains over the nuclei of the cells of these tissues. Androgen receptors were largely confined to the nuclei of the smooth muscle cells of the tunica muscularis of the gut wall and the connective tissue interstitial cells of the liver, pancreas, stomach, and intestines. Estrogen receptors were prominent in the nuclei of the vascular smooth muscle cells in the liver, pancreas, gut, and the majority of the endocrine islet cells. These observations suggest that a variety of different cell types of the liver, pancreas, and gastrointestinal tract contain estrogen and androgen receptors that might modulate their cellular activities and influence several different physiologic processes.

Estrogen receptor in the larynx of the aged baboon (Papio cynocephalus)

Using autoradiographic techniques, tritiated estrogen-receptor complex intranuclear labeling was identified in certain laryngeal tissues of four aged female baboons; no complex labeling was found in the control animal. Three significant findings were felt to be derived from this study. One, surface epithelium of the larynx had essentially no estrogen-receptor activity. Two, all tissues of mesenchymal origin, especially lamina propria, muscle, dense connective tissue, and fat had consistently high levels of nuclear localization of the labeled estrogen. The binding affinity seemed to be the highest at the anterior commissure and the immediate anterior subglottic space. Three, there was a high level of receptor binding in laryngeal cartilage and perichondrium. Since the activated hormone-receptor complex modulates gene expression to alter the amount of mRNA, sex steroids have a direct regulatory effect upon the target cell and, perhaps through an induction process, can exert an indirect effect upon adjacent tissues. It is postulated that since the larynx is a sexually dimorphic organ, the sex steroids and their receptors may play a role in altered phonation during aging and possibly in the development of laryngeal neoplasms and other diseases. Therefore, hormonal manipulation may play a future role in the therapy of laryngeal diseases. This study represents the first demonstration of estrogen receptors by specific anatomic location in the primate larynx with significant localization in the mesenchymal tissues but not in the epithelial tissues.

Cartilage of the baboon contains estrogen receptors

Castrated-adrenalectomized aged female baboons were injected with 3H-estradiol-17 B (E2) and killed one hour later. Specimens from all regions of the larynx and oral cavity were taken and processed for autoradiography. A consistent and heavy uptake of 3H-E2 by the perichondrium and cartilage was found in all laryngeal sections with cartilage present and in the articular cartilage of the condyle of the mandible. These data provide evidence that cartilage contains receptors for estrogen. These data along with data already present in the literature suggest that circulating estrogen may act directly on cartilage to modulate collagen synthesis and further that the loss in circulating estrogen associated with menopause might in part explain the large sexual dimorphism associated with the incidence of osteoarthritis.

Localization of a synthetic progestin in the reproductive organs of the female baboon

The uptake and retention of a radiolabeled synthetic progestin, ORG 2058, was studied in the female reproductive system of the baboon. Four estrogen-primed baboons were injected intravenously with 2.5 micrograms/kg body weight of 3H-ORG 2058. One animal, which served as a control, received an additional injection of 2.5 mg/kg body weight of unlabeled progesterone. One hour after the injections, the animals were killed and the uterus, cervix, oviduct, vagina, and labia were removed and processed for autoradiography. The cells in the germinative layers of the stratified squamous epithelium of the cervix, vagina, and labia demonstrated nuclear localization of the label. The columnar epithelium, both surface and glandular, of the uterus and cervix sequestered the synthetic steroid; however, the nuclei of the epithelium lining the oviduct were unlabeled. The nuclei of the fibroblasts and of the smooth muscle cells were labeled in all the organs studied. These preliminary observations suggest that there is a stage in the reproductive cycle in which progesterone receptors are contained in the stromal cells of the oviduct but are absent in the epithelium.