Endocrine Abstracts

We have previously reported that treatment in vivo with estrogenic compounds or vitamin D metabolites increased the specific activity of creatine kinase specific activity (CK) in different organs both in intact and in ovariectomized female rats. In the present study we assessed the hormonal responsiveness of para-uterine fat from female and epididymal fat from male rats. Injection of immature female rats with 5 μg estradiol-17β (E2), 50 μg of e...

3,5,3′-triiodothyronine (T3), regulates energy metabolism by oxygen consumption and thermogenesis via induction of NaK-ATPase in vivo. These changes are correlated with nuclear T3 binding in responsive organs. We showed that creatine kinase (CK) another ATP regulating enzyme, is modulated by different hormones, in tissues containing appropriate receptors. This modulation is via binding to specific receptors and changes in CK mRNA levels. Since CK is involved in en...

Vitamin D receptors (VDRs) are expressed in bone and vascular cells which also respond to vitamin D treatment by modulation of cell proliferation measured by DNA synthesis and energy metabolism measured by CK specific activity. We have previously observed that vitamin D-related compounds target several genes which affect cell proliferation, including mRNA expression of estrogen receptor (ER)α, ERβ, VDR, 1α hydroxylase of 25OHD3 (1OHase) and 12 and 15 lipoxygenas...

Ovariectomy of immature female rats, results in significant decrease of trabecular bone volume and in cortical bone thickness. Previously we found that estradiol-17β (E2) restored bone structure of ovariectomized female rats (Ovx) to values obtained in intact sham-operated female rats. E2 also selectively stimulated creatine kinase specific activity (CK) a hormonal-genomic activity marker. In the present study, we compared the effects of E2</sub...

We have previously demonstrated that rat bone cells in vivo and in vitro, responded sex-specifically to gonadal steroids in stimulation of the specific activity of creatine kinase (CK). Pretreatment with vitamin D analogs upregulated the sex-specific responsiveness and sensitivity to gonadal steroids. We also found that mice cultured femoral bone marrow (BM) in the presence of dexamethasone (DEX), 1.25(OH)2D3 (1.25D) or both, differentiated into osteoblast-like c...

Vitamin D metabolites modulate creatine kinase specific activity (CK) in cultured skeletal cells. In this study we assess the effect of vitamin D metabolites on CK in rat epiphyseal cartilage (Ep) and diaphyseal bone (Di). Female or male Wistar- derived rats were used either as intact or after gonadectomy (Ovx or cast respectively), and treatments started 2 weeks post surgery. Rats were injected daily for 1, 2 or 8 weeks with the less-calcemic vitamin D analogs CB 1093 (CB), J...

Several studies indicated that estrogen receptors (ERs) and vitamin D receptor (VDR), as well 1α-hydroxylase 25-hydroxy vitamin D (1OHase) are expressed in various normal and cancerous cell types. To date, there are no reported studies on the different expressions of VDR, 1OHase and ERs, in human thyroid normal and cancer cells. This study addresses these questions. Tissues harvested from papillary thyroid cancer (PTC) and normal glands explants were used throughout eithe...

Oestradiol-17β regulates diverse tissues and cells, both within and outside the reproductive system including human cancer cells. Currently used ERs agonists or antagonists are synthetic compounds prepared by structure modifications. Alternatively, peptide mimics of steroids would allow preparation of biased combinatorial libraries of chemical and biological origin, from which estrogenic peptides with tissue selective profiles can be selected. The phage-display peptide li...

We examined the response of rat female pituitary at different metabolic stages to treatments with estrogenic compounds and vitamin D analogs. Immature or ovariectomized (Ovx) female rats, responded by increased creatine kinase specific activity (CK) to estradiol-17β (E2), genistein (G), daidzein (D), biochainin A (BA), quecertin (Qu), carboxy- G (cG), carboxy- BA (cBA) and raloxifene (Ral). The response was inhibited when Ral was injected together with the estr...

Vitamin D receptors are widely expressed in the skeletal system, and vitamin D and its metabolites and analogs, exert a variety of biological activities such as regulation of cellular proliferation and differentiation, cell calcium transients and energy metabolism in vitro. The latter is exerted through the control of the brain type isozyme of creatine kinase specific activity (CK), which serves to provide a readily available reservoir for ATP generation under increased worklo...