The endocrinology and developmental biology of the prostate.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R M Bigsby
Publications and source records attributed to R M Bigsby.
Androgenic induction of DNA synthesis in prostatic glands induced in the urothelium of testicular feminized (Tfm/Y) mice.
It has been shown previously that wild-type urogenital sinus mesenchyme can induce the formation of prostate-like glandular structures in urinary bladder epithelium derived from adult Tfm (testicular feminization) mice. Total DNA synthesis within these tissue recombinants has been shown biochemically to be androgen sensitive. To determine which tissue (epithelium or stroma) accounts for this androgen-dependent DNA synthesis, an autoradiographic study was performed with tissue recombinants composed of rat wild-type urogenital sinus mesenchyme (UGM) associated with bladder epithelium from either wild-type (BLE) or Tfm mice (Tfm BLE). Both types of recombinants were grown under the kidney capsule of male athymic nude mice for 4 weeks. The hosts were then castrated, and 2 weeks later were treated with either testosterone propionate (TP), TP plus cyproterone acetate (CA), or oil vehicle for 3 days. DNA synthetic activity was measured through analysis of labelling index (LI) after incorporation of 3[H]-thymidine in vivo. For both UGM + BLE and UGM + Tfm BLE recombinants thymidine incorporation in epithelial cells greatly exceeded that of the stromal cells. TP stimulated epithelial LI to a similar degree (about 50- to 200-fold greater than controls) in both UGM + BLE and UGM + Tfm BLE recombinants; CA antagonized the effect of TP. Nuclear 3H-DHT binding was observed autoradiographically within the epithelial cells of the induced epithelium of UGM + wild-type BLE recombinants, but not within epithelium of UGM + Tfm BLE recombinants. Wild-type mesenchymal cells in both tissue recombinants showed specific nuclear 3H-DHT uptake. Thus, the proliferative effect of androgens upon prostatic epithelium is not a direct effect mediated by intra-epithelial androgen receptors, but rather it appears to be elicited indirectly via regulatory influences from androgen-receptor-positive stromal cells.
Androgens↗
Progesterone induces a secretory protein in cultured rabbit endometrial stromal cells.
Secretion of newly synthesized proteins by rabbit endometrial stromal cells in culture was studied. Progesterone (P) stimulated the synthesis and secretion of a protein with a mol. wt of approx 62 K and a pI of 6.5-7.0. Induction of 62 K protein synthesis was dose dependent; addition of 10 nM P to primary cultures caused a 2-fold or greater increase in the amount of this protein in the medium while addition of 1 microM P resulted in a 4.3-fold increase. Synthesis of this 62 K protein was not induced by estradiol, dexamethasone, or testosterone, nor was progesterone stimulation of the protein modified by estradiol. Thus, induction appears to be specific for a progesterone receptor mediated effect. Synthesis and secretion of this protein in the culture system described is potentially useful as a progestin bioassay.
Animals↗
Whole-mount autoradiography study of DNA synthetic activity during postnatal development and androgen-induced regeneration in the mouse prostate.
Ventral and dorsolateral prostatic lobes (VP and DLP), obtained from mice at different ages and at different intervals after castration or treatment of castrated males with testosterone propionate (TP), were microdissected into two-dimensional arrays and incubated in vitro with 14C-thymidine. Labeled whole-mount specimens were fixed and dried onto glass slides, dipped into photographic emulsion, and processed autoradiographically. The morphological pattern of DNA synthetic activity was similar in the VP and DLP. During early postnatal periods (10-15 days after birth), DNA synthetic activity was highest at the distal ductal tips (near the capsule) and considerably lower in proximal ducts (near the urethra). At 30 days of age, DNA synthesis was almost totally confined to the distal ducts, with exceedingly low labeling in the proximal ductal areas. In the prostate of the intact or castrated adult, DNA synthesis was nearly absent throughout the gland, but silver grains were still observed on the ductal tips. During androgen-induced prostatic regeneration, DNA synthesis was detectable only in distal ducts 24 h after TP was administered. Labeling intensity reached a maximum on the third day of TP treatment in both distal and proximal ductal areas, thereafter, it subsided to focal labeling confined mostly to distal ducts. These results demonstrate that levels of DNA synthetic activity vary considerably within the prostate on a regional basis. Explanation of this heterogeneity in DNA synthetic activity within the prostate gland is fundamental to understanding the mechanism of androgenic regulation of prostatic growth and development.
Aging↗
A simple efficient method for separating murine uterine epithelial and mesenchymal cells.
A simple, and very efficient, method for isolating pure uterine epithelium from neonatal, immature, or adult mice and pure uterine mesenchyme from neonatal mice is described. The technique uses mild tryptic digestion of the tissues to loosen the adherence of the epithelium to its underlying mesenchyme followed by gentle mechanical manipulation to effect removal of the luminal epithelium as an intact tube of cells. The epithelial fraction collected by this method was free of stromal cell contamination as judged by microscopic examination of the freshly isolated cells and of cell cultures made from that fraction. The mesenchymal fraction was consistently devoid of epithelium when collected from neonatal mice (5 days old or younger), but mesenchyme from uteri of mice greater than or equal to 10 days old was usually contaminated with epithelial cells due to retention of glandular epithelial crypts in the mesenchyme following removal of the luminal epithelium. Both epithelial and mesenchymal cells obtained by this method are viable, as judged by their ability to attach, spread, and synthesize DNA in vitro. Epithelial cells isolated from 20-day-old or adult animals have a full complement of estrogen receptors, as assessed by whole cell uptake of [3H]estradiol. The technique described here has clear advantages over previously described methods for obtaining pure uterine epithelium and in addition allows mesenchymal tissue free of epithelial contamination to be obtained when applied to uteri of animals less than or equal to 5 days old.
Aging↗
Estrogen stimulation of deoxyribonucleic acid synthesis in uterine epithelial cells which lack estrogen receptors.
Autoradiographic studies from this laboratory have previously indicated that the uterine epithelium of the neonatal mouse is devoid of estrogen receptors. The neonatal murine uterus is composed of an undifferentiated mesenchyme and a simple columnar epithelium lining the lumen. In the present study, a method for measuring whole cell uptake of 16 alpha-[125I]iodoestradiol ([125I]iodo-E2) was developed and applied to enzymatically separated, isolated epithelial and mesenchymal cells of neonatal (4-5 days postnatal) uteri. Epithelial cells and fibromuscular cells (stromal and myometrial cells) from uteri of 21-day-old animals were used to validate the assay method. A component of the uptake of [125I]iodo-E2 by cells from 21-day-old uteri was shown to be specific, saturable, and of high affinity. Kd values for specific uptake by uterine mesenchymal and epithelial cells were 1.2-1.3 nM. Maximal specific uptake was 9.3 and 4.2 fmol/micrograms DNA for epithelial and mesenchymal cells, respectively. The uterine epithelial cells of 4- and 5-day-old mice showed no measurable specific uptake of [125I]iodo-E2, while the mesenchymal cells from these animals had a maximal specific uptake of 7.9 fmol/micrograms DNA, with a Kd of 1.3 nM. DNA synthesis increased within the uterine epithelium of neonatal mice after estrogen treatment. The thymidine labeling index was doubled 10 h after a single dose of diethylstilbestrol (DES) and returned to pretreatment values by 18 h. The epithelial mitotic index was also 2-fold higher than control values 16-18 h after DES treatment. The increase in the thymidine labeling index was specific to estrogen treatment. DES did not induce the production of estrogen receptors in neonatal uterine epithelium. Epithelial cells of 5-day-old mice that were treated with DES showed no specific [125I]iodo-E2 uptake, while whole cell uptake by mesenchymal cells from these animals exhibited a specific, high affinity component, with a maximal binding of 8.4 fmol/micrograms DNA. Autoradiographic analysis of [3H]estradiol uptake by uterine tissues from 5-day-old mice 12 h after DES treatment did not show nuclear concentration of the steroid in the epithelial cells. These results indicate that the uterine epithelium of the neonatal mouse is indeed devoid of estrogen receptors, and yet the rate of DNA synthesis within this tissue is responsive to estrogen stimulation. The epithelial cells remain devoid of estrogen receptors after DES stimulation, indicating that intraepithelial estrogen receptors are not required for induction of DNA synthesis in these cells in situ. Possible mechanisms by which this phenomenon may occur are discussed.
Animals↗
Stromal-epithelial interactions in adult organs.
Explore the source record for details and available documents.
Aging↗
Effects of progestins and glucocorticoids on deoxyribonucleic acid synthesis in the uterus of the neonatal mouse.
The effects of progestins and glucocorticoids on cellular proliferation were examined in the uterus of 5-day-old mice by monitoring either the labeling index (LI) after exposure to [methyl-3H]thymidine ([3H]TdR) in vivo or the mitotic index (MI) after colchicine-induced arrest of cells in metaphase. In untreated 5-day-old mice, epithelial LI was 31%, and stromal LI was 15%. Eighteen hours after a single ip injection of 40 mg/kg progesterone, epithelial LI was reduced to 2.3% and remained low for 48 h. Stromal LI increased transiently, reaching a zenith (40%) 18 h after administration of progesterone and returning to control levels by 24 h. When mitotic activity was assessed 24 h after progesterone treatment, epithelial MI was decreased (control, 3.1%; progesterone, 0.23%) and stromal MI was increased (control, 0.60%; progesterone, 2.1%). Thus, the measured effects on LI were indicative of altered proliferative activity of the tissues. Glucocorticoids also inhibited epithelial LI, but had no effect on stromal LI. Eighteen hours after a single ip injection, dexamethasone inhibited epithelial LI to the same extent as progesterone treatment. Corticosterone did not significantly decrease epithelial LI, while cortisol produced an intermediate inhibitory response. To determine whether the high baseline LI in uterine epithelium of neonatal mice was estrogen dependent, uteri of 1-day-old mice were grafted under the kidney capsule of ovariectomized adult mice. Eight days later, the hosts were treated with either progesterone or vehicle and then killed 18 h later. After labeling the tissue with [methyl-3H]thymidine in vitro, the mean LI of the epithelium of the grafted uteri was 11.5%, while that of the vehicle-treated hosts was 0.10%. Progesterone treatment reduced the LI of the grafted uterine epithelium to 1.0%. These data demonstrate that uterine tissues of the neonatal mouse proliferate rapidly in the absence of gonadal steroids. Progestins and glucocorticoids specifically inhibit this estrogen-independent DNA synthesis of uterine epithelium.
Animals↗
Autoradiographic demonstration of high affinity nuclear binding and finite binding capacity of [3H]estradiol in mouse vaginal cells.
Vaginae from adult C57Bl/6J mice were analyzed for nuclear estrogen-binding sites by biochemical as well as in vitro steroid autoradiographic methods. Finite binding capacity (saturability) and high affinity binding were demonstrated in stromal cell nuclei (Kd = 1.0 nM) by autoradiographic methods and in nuclear extracts of vaginal homogenates (Kd = 1.9 nM) by biochemical techniques. The results of this study demonstrate that all criteria considered definitive for estrogen receptors can be met by autoradiographic analysis, which makes feasible the assessment of estrogen receptor activity in the individual cell types that comprise fetal and neonatal estrogen target organs.
Animals↗
Effects of passive immunization against oestradiol on mouse ovum transport.
The ability of anti-oestradiol immunoglobulin to withhold oestradiol-17 beta from its target tissue was examined. The total oestradiol-17 beta binding capacity present in in-vitro incubations or injected into mice intravenously was related to the amount of [3H]oestradiol present in the media or intravenously injected into the animals respectively. When the ratio of binding capacity to [3H]oestradiol was above 74:1, [3H]oestradiol was successfully withheld from uterine tissue in vitro and in vivo. Injecting anti-oestradiol immunoglobulin into mice before administration of a tube-locking dose of oestradiol-17 beta ensured normal passage of ova through the oviduct. Daily administration of anti-oestradiol immunoglobulin to PMSG-hCG stimulated mice (starting 72 h before hCG injection) induced retention of ova for at least 2 days beyond the time when all ova had left the oviducts of control animals. The binding capacity: oestradiol-17 beta concentration ratios of sera from these animals were greater than 250:1 throughout the experimental period. Non-specific immunoglobulin had no such effects, indicating the specificity of the anti-oestradiol immunoglobulin response.
Animals↗
Effects of physiological levels of estradiol-17 beta and progesterone on oviduct edema and ovum transport in the rabbit.
Explore the source record for details and available documents.
Animals↗
Effects of passive immunization against estradiol on rabbit ovum transport.
The role played by estradiol in control of ovum transport was studied in rabbits that were induced to ovulate by hCG stimulation. Withholding estrogen from target tissues during ovum transport by passive immunization with sheep anti-estradiol immunoglobulin (AE) resulted in accelerated oviductal transport and expulsion of ova from the uterus. The degree of accelerated transport was dependent on the duration of AE treatment. When AE treatment was started 24 h before hCG, fewer ova were recovered from the reproductive tracts at 72 h after hCG than were recovered from tracts of animals treated with a nonspecific immunoglobulin; the location of ova at 48 h after hCG was unaltered by this AE regimen. When AE treatment was started 72 h before hCG, fewer ova remained in the oviducts than were found in the tubes of controls at 48 h after hCG; and at 48 h after hCG, ova were found in the uteri of animals that had been treated with AE starting 72 h before hCG. When AE treatment was started 48 h before hCG, the position of eggs within the reproductive tract was not different from controls at 48 h after hCG. These observations support the concept that estrogen withdrawal is involved in the transport of ova through the oviduct of the rabbit, and suggest that the lack of estrogen secretion from the time of ovulation through the transport period is important in the control of normal ovum transport.
Animals↗