The metabolism of retinoic acid has been studied in subcellular fractions of hamster intestine and liver. This metabolism is induced in the tissues of vitamin Adeficient hamsters by pretreatment of the animals with oral doses of retinoic acid. The metabolic profile obtained after high pressure liquid chromatography reveals two major classes of metabolites, designated Peaks 4 and 5. Each of thes...

The chick limb bud is a powerful experimental system in which to study pattern formation in vertebrate embryos. Exogenously applied retinoic acid, a vitamin A derivative, can bring about changes in pattern and, on several grounds, is a good candidate for an endogenous morphogen. As such, the local concentration of retinoic acid might provide cells with information about their position in relati...

Alcohol dehydrogenase (ADH) participates in the formation of retinoic acid from retinol in various organs including the gastric mucosa. However, its clinical significance still remains to be clarified. In this study, we identified the ADH isoforms responsible for the retinoic acid formation among various ADH isoforms and examined associations among the ADH activities, the retinoic acid formatio...

A study was conducted to explore the effects of retinoic acid, fed to retinol-deficient rats, on the tissue distribution and levels of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP). Sensitive and specific radioimmunoassays were employed to measure the levels of both CRBP and CRABP. Two groups of six male rats each were fed a purified retinoid-deficie...

Protection of satellite cells from cytotoxic damages is crucial to ensure efficient adult skeletal muscle regeneration and to improve therapeutic efficacy of cell transplantation in degenerative skeletal muscle diseases. It is therefore important to identify and characterize molecules and their target genes that control the viability of muscle stem cells. Recently, we demonstrated that high ald...

The lateral plate mesoderm (LPM) lines the body cavities, gives rise to the heart and circulatory system and is responsible for patterning the underlying endoderm. We describe gene expression domains within the lateral plate mesoderm of the neurula stage Xenopus embryo that demonstrate a marked anterior posterior pattern in that tissue. FoxF1 and Nkx-2.5 are expressed in the anterior LPM, Hand1...

The production of interferon was used to study the site and mechanism of action of retinoic acid (vitamin A). The data are consistent with a site of action at the gene level, because it appears that interferon production is blocked at the transcriptional step by a retinoic acid-induced protein. (i) The effect of retinoic acid is probably on an early cellular function associated with interferon ...

The effects of all-trans retinoic acid on the development of the lateral line placodes of axolotls was studied. Late gastrula and early neurula were exposed to 10(-7) to 10(-5) M retinoic acid for one hour and then reared until they would normally be feeding larvae. As in other vertebrates, the extent of the developmental abnormalities is concentration dependent. Those embryos exposed to the hi...

Retinoic acid is like a steroid hormone that plays a role in embryo formation, proliferation of spermatogonia cells, ephitelial cells differentiation and organogenesis. Retinoic acid can influences seminiferous tubule formation during embryonic testis development and also play a role in the regulation of ovarian function and female reproductive tract by suppressing the hormones FSH receptor exp...

Astroglial cells are essential components of the neurogenic niches within the central nervous system. Emerging evidence suggests that they are among the key regulators of postnatal neurogenesis. Although astrocytes have been demonstrated to possess the potential to instruct stem cells to adopt a neuronal fate, little is known about the nature of the glia-derived instructive signals. Here we pro...