Search PubMed⌕ Search

Biomedical subjects

T C Spelsberg

Publications and source records attributed to T C Spelsberg.

211 records · Page 12Linked to original sources
PubMed1971

Soluble complexes between steroid hormones and target-tissue receptors bind specifically to target-tissue chromatin.

Cytoplasmic fractions containing steroid hormone receptor were prepared from rat prostate and uterine tissues, incubated first with [(3)H]dihydrotestosterone or [(3)H]estradiol, and then with their respective target and non-target tissue chromatins. Only prostate and testis chromatin bound the dihydrotestosterone-receptor complex from prostate cytosol extensively. Similarly, uterine chromatin bound more estradiol-receptor complex from uterus than did liver, spleen, or lung chromatin. Complexes between dihydrotestosterone or estradiol with cytosols prepared from liver and spleen bound less extensively, and similarly, to all chromatins. Analogous results are described for the [(3)H]progesterone-receptor complex from chick oviduct cytosol binding to oviduct chromatin. These studies suggest that the chromatin of all steroid hormone target tissues may contain "acceptor sites" for their respective hormone-receptor complexes, and are thus programmed to receive the complex as it is transferred into the nucleus from the cytoplasm of the cell.

Animals↗
PubMed1969

The interaction of RNA polymerase with histones.

Arginine-rich histones (F3) interact with both the bacterial and mammalian RNA polymerase and inhibit the in vitro RNA synthesis to a much greater extent than when associated with the DNA template. The lysine-rich histones (F1) inhibit the RNA synthesis mainly through template inhibition. Neither histone fraction displayed such an interaction with DNA polymerase. The RNA polymerase-F3 histone interaction takes place at ionic strength equal to or greater than those occurring in living cells, suggesting a possible role of arginine-rich histones in the regulation of RNA synthesis.

Adenosine Triphosphate↗
PubMedDate not supplied

Estrogen regulation of human osteoblast function is determined by the stage of differentiation and the estrogen receptor isoform.

Although osteoblasts have been shown to respond to estrogens and express both isoforms of the estrogen receptor (ER alpha and ER beta), the role each isoform plays in osteoblast cell function and differentiation is unknown. The two ER isoforms are known to differentially regulate estrogen-inducible promoter-reporter gene constructs, but their individual effects on endogenous gene expression in osteoblasts have not been reported. We compared the effects of 17 beta-estradiol (E) and tamoxifen (TAM) on gene expression and matrix formation during the differentiation of human osteoblast cell lines stably expressing either ER alpha (hFOB/ER alpha 9) or ER beta (hFOB/ER beta 6). Expression of the appropriate ER isoform in these cells was confirmed by northern and western blotting and the responses to E in the hFOB/ER beta 6 line were abolished by an ER beta-specific inhibitor. The data demonstrate that (1) in both the hFOB/ER cell lines, certain responses to E or TAM (including alkaline phosphatase, IL-6 and IL-11 production) are more pronounced at the late mineralization stage of differentiation compared to earlier stages, (2) E exerted a greater regulation of bone nodule formation and matrix protein/cytokine production in the ER alpha cells than in ER beta cells, and (3) the regulated expression of select genes differed between the ER alpha and ER beta cells. TAM had no effect on nodule formation in either cell line and was a less potent regulator of gene/protein expression than E. Thus, both the ER isoform and the stage of differentiation appear to influence the response of osteoblast cells to E and TAM.

Alkaline Phosphatase↗