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A D Loughney

Publications and source records attributed to A D Loughney.

5 recordsLinked to original sources
PubMed1996

Nuclear retinoid receptor expression in normal human endometrium throughout the menstrual cycle.

Previous work has shown that retinoic acid receptors (RARs) and retinoid X receptors (RXRs) are expressed in human endometrial epithelial and stromal cells. These nuclear receptors mediate the biological effects of retinoic acid, a vitamin A derivative which may have an important, though poorly characterized role in the functional differentiation of secretory epithelia. The aim of this study was to find out whether the expression of RAR and RXR mRNA in endometrial epithelial and stromal cells varies in relation to the menstrual cycle. The expression of RARs and RXRs was investigated by Northern blotting and, for stromal cells, there were no differences in expression of RAR-alpha, RAR-beta, RAR-gamma and RXR-alpha between the proliferative and secretory phases of the menstrual cycle. Similarly, for epithelial tissue, there were no significant differences between the proliferative and secretory phases with respect to the expression of RAR-alpha, RAR-gamma and RXR-alpha. However, RAR-beta was expressed at a 1.7-fold higher level in epithelial samples from the proliferative phase compared to the secretory phase. Overall, the levels of expression of RAR-alpha, RAR-beta and RAR-gamma were 1.7- to 4-fold higher in stromal cells compared to epithelial cells whereas RXR-alpha was expressed at a similar level in both cell types. We have previously suggested that retinoic acid has a role in endometrial differentiation or function which may be reflected by cyclical changes in intracellular retinoic acid levels. These data indicate that RARs and RXRs are expressed at a similar level throughout the menstrual cycle, with the possible exception of RAR-beta, implying that any menstrual cycle-related function of RARs in controlled by ligand availability rather than by changes in expression of the receptors.

Blotting, Northern↗
PubMed1995

Variation in the expression of cellular retinoid binding proteins in human endometrium throughout the menstrual cycle.

Human endometrium is a glandular epithelial tissue with a substantial underlying stroma. Under the influence of ovarian steroids, endometrium undergoes a cyclical pattern of proliferation followed by secretory differentiation. Since retinoids promote the differentiation of many epithelia to secretory phenotypes they may be involved in controlling the secretory differentiation of human endometrial epithelium. Cytosolic binding proteins for retinol (cellular retinol binding protein) and retinoic acid (cellular retinoic acid binding protein) may play an important part in regulating the availability of retinoic acid to its nuclear receptors and we have therefore asked whether expression of mRNA for these proteins varies in relation to endometrial differentiation. In a series of 54 endometrial biopsies, both endometrial epithelial and stromal cells expressed mRNA for cellular retinol binding protein type I at a constant level throughout the menstrual cycle. Cellular retinoic acid binding protein type II was also expressed but the level of expression varied dramatically, being elevated in the proliferative phase and depressed during the secretory phase of the menstrual cycle in both epithelial and stromal cells. These data suggest that cytosolic binding proteins modulate the supply of retinoic acid to the nuclei of endometrial cells during the menstrual cycle and that retinoic acid is involved in the cyclical control of endometrial differentiation.

Amino Acid Sequence↗
PubMed1995

Menstrual cycle related differences in the proliferative responses of cultured human endometrial stromal cells to retinoic acid.

Although ovarian-derived steroid hormones are central to the control of endometrial growth and secretory differentiation, all-trans retinoic acid, a derivative of vitamin A, may also play an important role. Since the retinoids can inhibit the proliferation of both fibroblasts and epithelial cells in experimental systems, we investigated whether the proliferation of endometrial stromal cells was inhibited by all-trans retinoic acid. A sensitive spectrophotometric assay was used to show that the proliferation rates of primary cultures of endometrial stromal fibroblasts varied with the timing of biopsy, and that all-trans retinoic acid inhibited the growth of late secretory phase cells but had no effect on cells sampled at other times. Furthermore, since the expression of mRNA encoding cellular retinoic acid binding protein type II decreases in endometrial stromal cells in the secretory phase, a rise in intracellular all-trans retinoic acid concentrations could be fundamental to the control of endometrial stromal cell proliferation and differentiation in vivo.

Analysis of Variance↗