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Biomedical subjects

C A Villee

Publications and source records attributed to C A Villee.

At least 37 records · Page 2Linked to original sources
PubMed1982

The variations of estrogen receptor, progesterone receptor, cAMP, ODC activity and RNA synthesis of deciduomata in pseudopregnant rats.

The present study was done to define the conditions of implantation of fertilized ovum from serial day-to-day changes in the tissue weight of deciduomata in pseudopregnancy, estrogen receptor (ER), progesterone receptor (PR), cAMP content, RNA synthesizing capacity and ornithine decarboxylase activity (ODC). Pseudopregnancy was induced in Wistar rats in the estrus morning by vaginocervical stimulation. At the 4th day of pseudopregnancy deciduomata was induced by intraluminal instillation of olive oil with simultaneous oophorectomy and intramuscular injection of 20 mg progesterone depot (the day of induction of decidualization was arbitrarily expressed as D0 and the ensuing days, as D1, D2 and so on). The number of binding sites of ER and PR was estimated by exchange assay using dextran charcoal. cAMP content and RNA synthesizing capacity were determined by RIA and 3H-UTP uptake, respectively. ODC activity was measured by the method of Jänne and Williams-Ashman. Following the induction of deciduomata the uterus weight (unilateral) increased abruptly to 2-fold at D2 and approximately 30-fold (4.5 g) at D8 and declined thereafter. ER diminished in a linear fashion from 2.77 x 10(-10) M at D2 to 0.53 x 10(-10) M at D7. On the other hand, PR was estimated 2.9 x 10(-10) at D2. 2.5 x 10(-10) M at D5 and decreased further at D6 and D7, cAMP was 77 nmoles/mg protein at D2 and decreased rapidly from D3 onward. RNA synthesizing capacity declined in a linear fashion from D3 to 1/2 to D5 and 1/3 at D7. ODC was found 1.7 CO2 nmoles/mg protein at D2, decreased at D3 and D4, but remained nearly the same at D4 and D5.

Animals↗
PubMed1982

Permissive role of the pituitary in the induction and growth of estrogen-dependent renal tumors.

Prolonged administration of estrogen to hamsters by implanted pellets induces not only renal adenocarcinomas but also enlarges pituitaries with hyperplastic and neoplastic changes, especially in the pars intermedia. The pituitaries of the diethylstilbestrol-implanted animals weigh 90 to 150 mg; those of control animals without diethylstilbestrol pellets weigh 7 to 12 mg. The enlarged pituitaries have 9.7 x 10(-10) M progesterone receptors compared to 0.75 x 10(-10) M in the controls. Castrated male hamsters were hypophysectomized, implanted with diethylstilbestrol pellets, fed laboratory chow ad libitum, and given 5% glucose in water to drink. New pellets were implanted every 3 months, and the animals survived for 12 to 15 months. At autopsy, none of the animals had a tumor. Sixty-two of 65 control castrated males with the same schedule of pellet implantation developed tumors. Hypophysectomized castrated males implanted with diethylstilbestrol pellets were given daily injections of 1 microgram each of follicle-stimulating hormone, luteinizing hormone, and prolactin; or with 0.9% NaCl solution. These animals survived for 12 to 15 months, but none developed kidney tumors. Other castrated males were hypophysectomized and implanted with diethylstilbestrol pellets, and 2 months later tumor tissues were transplanted under the kidney capsule. Eighty days later, no tumors were evident in the kidneys of these animals. Control castrated males were implanted with diethylstilbestrol pellets, and 2 months later tumor tissue was transplanted under the kidney capsule. Between 60 and 85 days later, 13 of the 15 controls had developed renal tumors. The concentrations of follicle-stimulating hormone, luteinizing hormone, and prolactin were measured by radioimmunoassays. The concentrations of circulating follicle-stimulating hormone and luteinizing hormone in animals with diethylstilbestrol implants decreased with time and, by 7 months, were similar to those in hypophysectomized animals. The concentration of prolactin in animals with diethylstilbestrol pellets increased with time and reached twice the value in the control animals without diethylstilbestrol pellets. These studies suggest that some factor secreted by the pituitary may be involved as a promoter or a cocarcinogen in the estrogen induction of kidney tumors.

Animals↗
PubMed1979

Increased progesterone receptor concentrations in bladder lesions of estrogen-treated Syrian hamsters.

During studies of renal tumorigenesis induced by estrogen in Syrian hamsters, we have observed that about 15 to 20% of animals develop bladder lesions with an increased wet weight of tissue from 0.2 g to 0.4 to 1.7 g. Histological examination of the lesions showed a spectrum of changes from inflammatory reactions to squamous metaplasia and intense hyperplasia of the transitional epithelium. The concentration of progesterone-binding sites was increased in the bladders with lesions. No specific progesterone-binding sites could be detected in the cytosol of bladders from hamsters not treated with estrogen. The affinity constant for the progesterone-binding sites in cytosol from bladders with lesions was 10(9) M-1, the same as that reported for progesterone receptors in other target tissues for estrogen. The binding sites are specific for progesterone and are not competed for by 17 beta-estradiol, 5 alpha-dihydrotestosterone, or aldosterone.

Aldosterone↗
PubMed1977

Changes in estrogen receptor levels during deciduomata development in the pseudopregnant rat.

The presence of a cytoplasmic estradiol receptor with an affinity constant of 10(10)M-1 has been demonstrated in the differentiated fibroblasts comprising the deciduomata in pseudopregnant rats. The receptor had a sedimentation coefficient of 6S in sucrose density gradients containing a physiological concentration of salt, and estradiol binding was completely abolished by a hundred-fold excess of unlabeled estradiol. During the early stages of decidualization (days 2 and 3), the decidualized uterine horn or isolated deciduomal tissue contained a concentration of receptor comparable to that in non-gravid uteri from rats ovariectomized at estrus. By day 5 of decidualization, the concentration of estradiol binding in deciduomal tissue decreased to about one-half the concentration measurable at days 2 and 3 of decidualization despite continued tissue growth until day 7. By day 7 of decidualization, estradiol binding had decreased to about 20% of the concentration on days 2 and 3 of decidualization. Cytosol from untreated uterine horns of rats bearing deciduomata bound the same amount of estradiol through day 7 as that in uteri of rats ovariectomized at estrus. These observations are discussed in terms of steroid hormone involved in deciduomal growth and regression.

Animals↗
PubMed1977

Changes in progesterone receptor levels during deciduomata development in the pseudopregnant rat.

A specific cytoplasmic progesterone receptor has been identified and quantified in the deciduomata of the pseudopregnant rat. The receptor had a sedimentation coefficient of 6-7S on sucrose density gradients and was inactivated by proteolytic enzymes, sulfhydryl blocking agents and elevated temperature. The equilibrium association constant for the binding of progesterone by the deciduomal receptor was determined to be approximately 10(9)M-1. The concentrations of progesterone receptor sites in cytosols prepared from deciduomata on day 3 and 5 of decidualization were 3.4 +/- 0.3 X 10(-10)M and 3.6 +/- 0.4 X 10(10)M, respectively, when normalized to a protein concentration of 1 mg/ml. These concentrations of progesterone receptor sites were similar to that measured in the uterine cytosol of estrous rats or in the contralateral untreated uterine horn of rats undergoing decidualization. Following day 5 of decidualization the concentrations of progesterone receptor sites decreased linearly so that by day 7 the concentration was approximately one-half that at days 3 and 5. The physiological significance of the progesterone receptor and the decrease in its concentration with time are discussed with regard to their influence on the decidualization reaction.

Animals↗
PubMed1976

Structure of eukaryotic chromatin. Evaluation of periodicity using endogenous and exogenous nucleases.

DNA isolated from (a) liver chromatin digested in situ with endogenous Ca2+, Mg2+-dependent endonuclease, (b) prostate chromatin digested in situ with micrococcal nuclease or pancreatic DNAase I, and (c) isolated liver chromatin digested with micrococcal nuclease or pancreatic DNAase I has been analyzed electrophoretically on polyacrylamide gels. The electrophoretic patterns of DNA prepared from chromatin digested in situ with either endogenous endonuclease (liver nuclei) or micrococcal nuclease (prostate nuclei) are virtually identical. Each pattern consists of a series of discrete bands representing multiples of the smallest fragment of DNA 200 +/- 20 base pairs in length. The smallest DNA fragment (monomer) accumulates during prolonged digestion of chromatin in situ until it accounts for nearly all of the DNA on the gel; approx. 20% of the DNA of chromatin is rendered acid soluble during this period. Digestion of liver chromatin in situ in the presence of micrococcal nuclease results initially in the reduction of the size of the monomer from 200 to 170 base pairs of DNA and subsequently results in its conversion to as many as eight smaller fragments. The electrophoretic pattern obtained with DNA prepared from micrococcal nuclease digests of isolated liver chromatin is similar, but not identical, to that obtained with liver chromatin in situ. These preparations are more heterogeneous and contain DNA fragments smaller than 200 base pairs in length. These results suggest that not all of the chromatin isolated from liver nuclei retains its native structure. In contrast to endogenous endonuclease and micrococcal nuclease digests of chromatin, pancreatic DNAase I digests of isolated chromatin and of chromatin in situ consist of an extremely heterogeneous population of DNA fragments which migrates as a continuum on gels. A similar electrophoretic pattern is obtained with purified DNA digested by micrococcal nuclease. The presence of spermine (0.15 mM) and spermidine (0.5 mM) in preparative and incubation buffers decreases the rate of digestion of chromatin by endogenous endonuclease in situ approx. 10-fold, without affecting the size of the resulting DNA fragments. The rates of production of the smallest DNA fragments, monomer, dimer, and trimer, are nearly identical when high molecular weight DNA is present in excess, indicating that all of the chromatin multimers are equally susceptible to endogenous endonuclease. These observations points out the effects of various experimental conditions on the digestion of chromatin by nucleases.

Animals↗