Detail of "1256-86-6"

Reference

Regulation of proliferation and differentiation of respiratory tract epithelial cells by TGFb

Regulation of proliferation and differentiation of respiratory tract epithelial cells by TGFb. Jetten, Anton M.; Shirley, Jill E.; Stoner, Gary (Lab. Pulmonary Pathobiol., Natl. Inst. Environ. Health Sci., Research Triangle Park, NC 27709, USA). Exp. Cell Res., 167(2), 539-49 (English) 1986. CODEN: ECREAL. ISSN: 0014-4827. 302-79-4 and 7440-70-2 which are cas registry numbers are also used here. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Treatment of rabbit tracheal epithelial cells in primary culture with transforming growth factor-b (TGFb) inhibits cell proliferation in a time- and dose-dependent manner; concns. as low as 1 pM inhibit cell growth . Concomitantly, TGFb causes cells to accumulate in the G0/G1 phase of the cell cycle and a sharp redn. in the ability of the cells to form colonies after subculture at clonal d. Apparently, TGFb induces terminal cell division in these cells. The inhibition of cell growth is accompanied by changes in cell morphol. and a stimulation of the formation of crosslinked envelopes. TGFb enhances the levels of transglutaminase [80146-85-6] activity and cholesterol sulfate [1256-86-6], 2 markers of squamous differentiation. Thus, TGFb induces terminal squamous cell differentiation in rabbit tracheal epithelial cells. Retinoic acid [302-79-4] does not affect the commitment to terminal cell division induced by TGFb, but inhibits the expression of the squamous phenotype. Growth of normal human bronchial epithelial cells was affected by TGFb in a way similar to that of rabbit tracheal epithelial cells. Several carcinoma cell lines tested were quite resistant to TGFb, whereas growth of 1 carcinoma cell line was stimulated by TGFb. A modified response to TGFb could be a mechanism involved in the aberrant growth control of malignant cells. .

Binding and hydroxylation of sulfoconjugated steroids in adrenal cortex mitochondria

Binding and hydroxylation of sulfoconjugated steroids in adrenal cortex mitochondria. Montelius, J.; Gustafsson, J. A.; Ingelman-Sundberg, M.; Rydstrom, J. (Arrhenius Lab., Univ. Stockholm, Stockholm, Swed.). Biochim. Biophys. Acta, 488(3), 502-11 (English) 1977. CODEN: BBACAQ. DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Section cross-reference(s): 13 Binding and hydroxylation of deoxycorticosterone 21-sulfate (I) [1420-82-2], testosterone 17-sulfate [651-45-6], cholesterol 3-sulfate [1256-86-6], and the corresponding free steroids by the hydroxylase systems in bovine mitochondria were studied. I bound to cytochrome P-450 [9035-51-2] and gave rise to a type I difference spectrum with a peak at 388 nm and a trough at 422 nm similar to that produced by deoxycorticosterone [64-85-7]. The max. extents of absorption change were similar for the free and the sulfoconjugated steroid. However, the concn. required for 1/2-max. binding to cytochrome P-450 was .apprx.2 orders of magnitude lower for the free steroid as compared to the sulfoconjugated steroid. Similar results were obtained with testosterone [58-22-0] and testosterone 17-sulfate. The absorption changes produced by deoxycortisterone and testosterone were not additive, indicating that these steroids bound to the same species of cytochrome P-450. With either of these steroids, addn. of the corresponding sulfoconjugated steroid did not result in further absorption change, suggesting that free and sulfoconjugated steroid bind to the same species of cytochrome P-450. Also, it appearred that the same species of cytochrome P-450 binds both cholesterol [57-88-5] and cholesterol 3-sulfate. With malate as reducing agent, I was hydroxylated by mitochondria to corticosterone 21-sulfate at a rate of .apprx.0.075 nmol/min/mg protein, i.e. .apprx.7% of the rate of hydroxylation of the free steroid. Neither testosterone 17-sulfate nor testosterone was hydroxylated at any appreciable rate. In intact adrenal cortex mitochondria, sulfoconjugated steroids may be metabolized by the normal pathways for the free steroids but at decreased rates.