scholarly journals Retinoic Acid Metabolism and Signaling Pathways in the Adult and Developing Mouse Testis

Endocrinology ◽  
2006 ◽  
Vol 147 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Nadège Vernet ◽  
Christine Dennefeld ◽  
Cécile Rochette-Egly ◽  
Mustapha Oulad-Abdelghani ◽  
Pierre Chambon ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Retinoic Acid ◽  
Vitamin A ◽  
Signaling Pathways ◽  
Sertoli Cells ◽  
Vitamin A Deficiency ◽  
Expression Patterns ◽  
Mouse Testis ◽  
Cytochrome P450 Hydroxylase ◽  
Lecithin:Retinol Acyltransferase

As a first step in investigating the role of retinoic acid (RA) in mouse testis, we analyzed the distribution pattern of the enzymes involved in vitamin A storage (lecithin:retinol acyltransferase), RA synthesis (β-carotene 15,15′-monoxygenase and retinaldehyde dehydrogenases) and RA degradation (cytochrome P450 hydroxylases) as well as those of all isotypes of receptors transducing the RA signal [RA receptors (RARs) and rexinoid receptors (RXRs)]. Our data indicate that in adult testis 1) cytochrome P450 hydroxylase enzymes may generate in peritubular myoid cells a catabolic barrier that prevents circulating RA and RA synthesized by Leydig cells to enter the seminiferous epithelium; 2) the compartmentalization of RA synthesis within this epithelium may modulate, through paracrine mechanisms, the coupling between spermatogonia proliferation and spermatogenesis; 3) retinyl esters synthesized in round spermatids by lecithin:retinol acyltransferase may be transferred and stored in Sertoli cells, in the form of adipose differentiation-related protein-coated lipid droplets. We also show that RARα and RXRβ are confined to Sertoli cells, whereas RARγ is expressed in spermatogonia and RARβ, RXRα, and RXRγ are colocalized in step 7–8 spermatids. Correlating these expression patterns with the pathological phenotypes generated in response to RAR and RXR mutations and to postnatal vitamin A deficiency suggests that spermiation requires RXRβ/RARα heterodimers in Sertoli cells, whereas spermatogonia proliferation involves, independently of RXR, two distinct RAR-mediated signaling pathways in both Sertoli cells and spermatogonia. Our data also suggest that the involvement of RA in testis development starts when primary spermatogonia first appear.

scholarly journals Spermatogonia Differentiation Requires Retinoic Acid Receptor γ

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 438-449 ◽  
Author(s):  
Aurore Gely-Pernot ◽  
Mathilde Raverdeau ◽  
Catherine Célébi ◽  
Christine Dennefeld ◽  
Betty Feret ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Nuclear Receptor ◽  
Sertoli Cells ◽  
Retinoic Acid Receptor ◽  
Vitamin A Deficiency ◽  
Seminiferous Tubules ◽  
Wild Type ◽  
Differentiation Markers ◽  
Selective Agonists

Vitamin A is instrumental to mammalian reproduction. Its metabolite, retinoic acid (RA), acts in a hormone-like manner through binding to and activating three nuclear receptor isotypes, RA receptor (RAR)α (RARA), RARβ, and RARγ (RARG). Here, we show that 1) RARG is expressed by A aligned (Aal) spermatogonia, as well as during the transition from Aal to A1 spermatogonia, which is known to require RA; and 2) ablation of Rarg, either in the whole mouse or specifically in spermatogonia, does not affect meiosis and spermiogenesis but impairs the Aal to A1 transition in the course of some of the seminiferous epithelium cycles. Upon ageing, this phenomenon yields seminiferous tubules containing only spermatogonia and Sertoli cells. Altogether, our findings indicate that RARG cell-autonomously transduces, in undifferentiated spermatogonia of adult testes, a RA signal critical for spermatogenesis. During the prepubertal spermatogenic wave, the loss of RARG function can however be compensated by RARA, as indicated by the normal timing of appearance of meiotic cells in Rarg-null testes. Accordingly, RARG- and RARA-selective agonists are both able to stimulate Stra8 expression in wild-type prepubertal testes. Interestingly, inactivation of Rarg does not impair expression of the spermatogonia differentiation markers Kit and Stra8, contrary to vitamin A deficiency. This latter observation supports the notion that the RA-signaling pathway previously shown to operate in Sertoli cells also participates in spermatogonia differentiation.

Complex regulation of TGF beta expression by retinoic acid in the vitamin A-deficient rat

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1081-1086 ◽  
Author(s):  
A.B. Glick ◽  
B.K. McCune ◽  
N. Abdulkarem ◽  
K.C. Flanders ◽  
J.A. Lumadue ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Alveolar Epithelium ◽  
Tgf Beta ◽  
Basal Expression ◽  
Beta 2 ◽  
Complex Regulation ◽  
First Time

We report the results of a histochemical study, using polyclonal antipeptide antibodies to the different TGF beta isoforms, which demonstrates that retinoic acid regulates the expression of TGF beta 2 in the vitamin A-deficient rat. Basal expression of TGF beta 2 diminished under conditions of vitamin A deficiency. Treatment with retinoic acid caused a rapid and transient induction of TGF beta 2 and TGF beta 3 in the epidermis, tracheobronchial and alveolar epithelium, and intestinal mucosa. Induction of TGF beta 1 expression was also observed in the epidermis. In contrast to these epithelia, expression of the three TGF beta isoforms increased in vaginal epithelium during vitamin A deficiency, and decreased following systemic administration of retinoic acid. Our results show for the first time the widespread regulation of TGF beta expression by retinoic acid in vivo, and suggest a possible mechanism by which retinoics regulate the functions of both normal and pre-neoplastic epithelia.

scholarly journals A new approach to the assessment of marginal vitamin A deficiency in children in suburban Guwahati, India: hydrolysis of retinoyl glucuronide to retinoic acid

2008 ◽  
Vol 101 (6) ◽  
pp. 794-797 ◽  
Author(s):  
Pulin C. Sarma ◽  
Bhabesh C. Goswami ◽  
Krishna Gogoi ◽  
Harsha Bhattacharjee ◽  
Arun B. Barua
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Serum Retinol ◽  
Serum Samples ◽  
Group I ◽  
High Prevalence ◽  
Hydrolysis Of ◽  
Β Carotene

The objective of the present study was to determine marginal vitamin A deficiency (VAD) by testing the hydrolysis of retinoyl glucuronide (RAG) to retinoic acid (RA) in children. Previous studies in rats showed that hydrolysis occurred when rats were vitamin A deficient. Children (n 61) aged 3–18 years, were divided into two groups, I and II. Blood was collected from the children in Group I (n 19) who were not dosed with RAG. Children in Group II (n 42) were administered all-trans retinoyl glucuronide (RAG) orally, and blood was collected 4 h after the dose. All serum samples were analysed for retinoids and carotenoids. RA was detected in serum only when serum retinol was < 0·85 μmol/l. Thus, hydrolysis of RAG to RA occurred in children with VAD or marginal VAD. Serum retinol was < 0·35 μmol/l in twenty-one children, 0·35–0·7 μmol/l in twenty-three children, 0·7–0·9 μmol/l in eleven children and >1 μmol/l in six children. Mean serum retinol in sixty-one children was 0·522 (sd 0·315) μmol/l. Mean β-carotene (0·016 (sd 0·015) μmol/l) was far below normal compared to the level of lutein (0·176 (sd 0·10) μmol/l) in sixty-one children. A low β-carotene level might be due to a low intake of carotene but high demand for vitamin A. The RAG hydrolysis test may prove to be a useful approach for the determination of marginal VAD with no clinical or subclinical signs of VAD. High prevalence of VAD amongst certain communities in Assam cannot be ruled out.

scholarly journals Role of Vitamin A in Mammary Gland Development and Lactation

Nutrients ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 80 ◽  
Author(s):  
M. Teresa Cabezuelo ◽  
Rosa Zaragozá ◽  
Teresa Barber ◽  
Juan R. Viña
Keyword(s):  
Retinoic Acid ◽  
Mammary Gland ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Retinoid Signaling ◽  
Nutritional Problem ◽  
Pregnancy And Lactation ◽  
Gland Development

Vitamin A (all-trans-retinol), its active derivatives retinal and retinoic acid, and their synthetic analogues constitute the group of retinoids. It is obtained from diet either as preformed vitamin A or as carotenoids. Retinal plays a biological role in vision, but most of the effects of vitamin A are exerted by retinoic acid, which binds to nuclear receptors and regulates gene transcription. Vitamin A deficiency is an important nutritional problem, particularly in the developing world. Retinol and carotenoids from diet during pregnancy and lactation influence their concentration in breast milk, which is important in the long term, not only for the offspring, but also for maternal health. In this study, we review the role of vitamin A in mammary gland metabolism, where retinoid signaling is required not only for morphogenesis and development of the gland and for adequate milk production, but also during the weaning process, when epithelial cell death is coupled with tissue remodeling.

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