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Santillo A, Chieffi Baccari G, Minucci S, Falvo S, Venditti M, Di Matteo L. The Harderian gland: Endocrine function and hormonal control. Gen Comp Endocrinol 2020; 297:113548. [PMID: 32679156 DOI: 10.1016/j.ygcen.2020.113548] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 01/17/2023]
Abstract
The Harderian gland (HG) is an exocrine gland located within the eye socket in a variety of tetrapods. During the 1980s and 1990s the HG elicited great interest in the scientific community due to its morphological and functional complexity, and from a phylogenetic point of view. A comparative approach has contributed to a better understanding of its physiology. Whereas the chemical nature of its secretions (mucous, serous or lipids) varies between different groups of tetrapods, the lipids represent the more common component among different species. Indeed, besides being an accessory to lubricate the nictitating membrane, the lipids may have a pheromonal function. Porphyrins and melatonin secretion is a feature of the rodent HG. The porphyrins, being phototransducers, could modulate HG melatonin production. The melatonin synthesis suggests an involvement of the HG in the retinal-pineal axis. Finally, StAR protein and steroidogenic enzyme activities in the rat HG suggests that the gland contributes to steroid hormone synthesis. Over the past twenty years, much has become known on the hamster (Mesocricetus auratus) HG, unique among rodents in displaying a remarkable sexual dimorphism concerning the contents of porphyrins and melatonin. Mainly for this reason, the hamster HG has been used as a model to compare, under normal conditions, the physiological oxidative stress between females (strong) and males (moderate). Androgens are responsible for the sexual dimorphism in hamster and they are known to control the HG secretory activity in different species. Furthermore, HG is a target of pituitary, pineal and thyroid hormones. This review offers a comparative panorama of the endocrine activity of the HG as well as the hormonal control of its secretory activity, with a particular emphasis on the sex dimorphic aspects of the hamster HG.
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Affiliation(s)
- Alessandra Santillo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania 'Luigi Vanvitelli', Via Vivaldi, 43-81100 Caserta, Italy.
| | - Gabriella Chieffi Baccari
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania 'Luigi Vanvitelli', Via Vivaldi, 43-81100 Caserta, Italy
| | - Sergio Minucci
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate, Università degli Studi della Campania 'Luigi Vanvitelli', via Santa Maria di Costantinopoli, 16-80138 Napoli, Italy
| | - Sara Falvo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania 'Luigi Vanvitelli', Via Vivaldi, 43-81100 Caserta, Italy
| | - Massimo Venditti
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate, Università degli Studi della Campania 'Luigi Vanvitelli', via Santa Maria di Costantinopoli, 16-80138 Napoli, Italy
| | - Loredana Di Matteo
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate, Università degli Studi della Campania 'Luigi Vanvitelli', via Santa Maria di Costantinopoli, 16-80138 Napoli, Italy
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Santillo A, Burrone L, Falvo S, Senese R, Lanni A, Chieffi Baccari G. Triiodothyronine induces lipid oxidation and mitochondrial biogenesis in rat Harderian gland. J Endocrinol 2013; 219:69-78. [PMID: 23873539 DOI: 10.1530/joe-13-0127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The rat Harderian gland (HG) is an orbital gland producing a copious lipid secretion. Recent studies indicate that its secretory activity is regulated by thyroid hormones. In this study, we found that both isoforms of the thyroid hormone receptor (Trα (Thra) and Trβ (Thrb)) are expressed in rat HGs. Although Thra is expressed at a higher level, only Thrb is regulated by triiodothyronine (T3). Because T3 induces an increase in lipid metabolism in rat HGs, we investigated the effects of an animal's thyroid state on the expression levels of carnitine palmitoyltransferase-1A (Cpt1a) and carnitine palmitoyltransferase-1B (Cpt1b) and acyl-CoA oxidase (Acox1) (rate-limiting enzymes in mitochondrial and peroxisomal fatty acid oxidation respectively), as well as on the mitochondrial compartment, thereby correlating mitochondrial activity and biogenesis with morphological analysis. We found that hypothyroidism decreased the expression of Cpt1b and Acox1 mRNA, whereas the administration of T3 to hypothyroid rats increased transcript levels. Respiratory parameters and catalase protein levels provided further evidence that T3 modulates mitochondrial and peroxisomal activities. Furthermore, in hypothyroid rat HGs, the mitochondrial number and their total area decreased with respect to the controls, whereas the average area of the individual mitochondrion did not change. However, the average area of the individual mitochondrion was reduced by ∼50% in hypothyroid T3-treated HGs, and the mitochondrial number and the total area of the mitochondrial compartment increased. The mitochondrial morphometric data correlated well with the molecular results. Indeed, hypothyroid status did not modify the expression of mitochondrial biogenesis genes such as Ppargc1a, Nrf1 and Tfam, whereas T3 treatment increased the expression level of these genes.
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Affiliation(s)
- A Santillo
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università degli Studi di Napoli, via Vivaldi, 43, 81100 Caserta, Italy
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Santillo A, Burrone L, Minucci S, Di Giovanni M, Chieffi Baccari G. Molecular pathways involved in the cyclic activity of frog (Pelophylax esculentus) Harderian gland: Influence of temperature and testosterone. Comp Biochem Physiol B Biochem Mol Biol 2011; 158:71-6. [DOI: 10.1016/j.cbpb.2010.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 09/14/2010] [Accepted: 09/17/2010] [Indexed: 01/01/2023]
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Serino I, Izzo G, Ferrara D, d’Istria M, Minucci S. A new sex dimorphism in the Harderian gland of the frog Rana esculenta. CAN J ZOOL 2007. [DOI: 10.1139/z07-072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Harderian gland (Hg), the only gland found in the orbit of the frog Rana esculenta L., 1758, probably plays a role in orbital lubrication. The secretory activity of the Hg is seasonal, showing the highest activity in summer. There is little information on Hg gene expression; previously, we identified a mRNA named harderin, whose deduced protein has no homology with other proteins. Differential expression of the harderin transcript between the sexes expressed during the annual cycle implies sexual dimorphism. RT–PCR (reverse transcription – polymerase chain reaction) analysis, revealed that harderin is expressed during the entire year in the Hg of both sexes. It shows a higher level of expression in the female glands than that of male glands. Two peaks of expression, in February and in June, were observed in the female glands, while only the February peak was observed in those of males. These observations were supported by in situ hybridization. Experiments involving gonadectomy and (or) hormonal replacement therapy showed a significant decrease in harderin in the Hg of females; this effect is prevented by estradiol (testosterone had no effect), while ICI (antiestrogen) counteracts the hormonal prevention, suggesting that this sexual dimorphism is under estradiol control. The constant expression of harderin mRNA during the year suggests a probable constitutive role for this molecule.
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Affiliation(s)
- Ismene Serino
- Dipartimento di Medicina Sperimentale – Sezione di Fisiologia Umana e Funzioni Biologiche Integrate “F. Bottazzi”, Facoltà di Medicina e Chirurgia, Seconda Università degli Studi di Napoli, via Costantinopoli 16, 80138 Napoli, Italy
| | - Gaia Izzo
- Dipartimento di Medicina Sperimentale – Sezione di Fisiologia Umana e Funzioni Biologiche Integrate “F. Bottazzi”, Facoltà di Medicina e Chirurgia, Seconda Università degli Studi di Napoli, via Costantinopoli 16, 80138 Napoli, Italy
| | - Diana Ferrara
- Dipartimento di Medicina Sperimentale – Sezione di Fisiologia Umana e Funzioni Biologiche Integrate “F. Bottazzi”, Facoltà di Medicina e Chirurgia, Seconda Università degli Studi di Napoli, via Costantinopoli 16, 80138 Napoli, Italy
| | - Michela d’Istria
- Dipartimento di Medicina Sperimentale – Sezione di Fisiologia Umana e Funzioni Biologiche Integrate “F. Bottazzi”, Facoltà di Medicina e Chirurgia, Seconda Università degli Studi di Napoli, via Costantinopoli 16, 80138 Napoli, Italy
| | - Sergio Minucci
- Dipartimento di Medicina Sperimentale – Sezione di Fisiologia Umana e Funzioni Biologiche Integrate “F. Bottazzi”, Facoltà di Medicina e Chirurgia, Seconda Università degli Studi di Napoli, via Costantinopoli 16, 80138 Napoli, Italy
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De Rienzo G, Di Sena R, Ferrara D, Palmiero C, Chieffi Baccari G, Minucci S. Temporal and spatial localization of prothymosin alpha transcript in the Harderian gland of the frog, Rana esculenta. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2002; 292:633-9. [PMID: 12115928 DOI: 10.1002/jez.10097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Harderian gland (hg) is the only orbital gland of the frog Rana esculenta, and it has the essential function of lubricating the eyes. The hg secretory activity is seasonal, showing the highest value in summer. There is, at present, no data on gene expression of the frog hg. This study reports, for the first time, on the temporal and spatial expression of a cDNA clone encoding for the prothymosin alpha (Prot-alpha), a highly acidic nuclear protein present in virtually all mammalian cells. Northern blot analysis revealed a single 1.7 kb transcript detected in the frog hg throughout the year, with a lowest expression in September in concomitance with the minimum secretory activity. In situ hybridization indicated that hg secretory cells express Prot-alpha transcript, and the hybridization signal was less intense in the September gland. The constant expression of the frog Prot-alpha mRNA during the whole year suggests a constitutive role for this molecule in the hg. In addition, taking into account that, in mammals, many immunomodulatory functions have been attributed to this protein, it is suggested that frog Prot-alpha might contribute to the hg immunity processes, probably acting as a protective agent against infections of the eyeball. Interestingly, although the presence of Prot-alpha gene in animals other than mammals has been considered to be highly unlikely, the present paper confirms the presence of Prot-alpha transcript in a nonmammalian vertebrate, the frog R. esculenta.
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Affiliation(s)
- Gianluca De Rienzo
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia Umana e Funzioni Biologiche Integrate, F. Bottazzi, Seconda Università degli Studi di Napoli, 80138 Napoli, Italy
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Varriale B, Chieffi P. Oestrogen control of the sexual dimorphism in the Harderian gland of Xenopus laevis. J Steroid Biochem Mol Biol 1997; 62:455-60. [PMID: 9449249 DOI: 10.1016/s0960-0760(97)00050-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Xenopus laevis shows a sexual dimorphism of the electrophoretic pattern of Harderian gland (HG) proteins. The male pattern displays three protein fractions whose molecular sizes are approx. 205, 180 and 78 kDa, respectively, and which are absent in the female pattern. Conversely, the female pattern displays two protein fractions of approx. 190 and 76 kDa, respectively. This sexual dimorphism led us to hypothesize a sex steroid control of the HG. Administration of 17beta-oestradiol to male Xenopus converts the male protein pattern into the female one, while the administration of testosterone to the female has no effect. In this respect neither Northern analysis nor the RNase-protection assay performed using a 213 bp encoding for the androgen-binding domain reveals the presence of an androgen receptor mRNA in Xenopus HG. Conversely, Northern analysis has shown an oestrogen receptor mRNA whose size is approx. 6.5 kb and the RNase-protection assay performed by using a 197 bp encoding for the oestrogen-binding domain has also displayed the presence of an oestrogen receptor mRNA in the female HG but not in the male one. In addition, the oestrogen administration to male Xenopus induces the appearance of an oestrogen receptor mRNA. Androgen administration to female toad is ineffective. Taken together, all these findings suggest that in Xenopus laevis oestrogens are involved into the HG physiology. The appearance of an oestrogen receptor mRNA in the oestradiol treated males supports the hypothesis of the occurrence of autoinduction of oestrogen receptor mRNA expression in the HG.
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Affiliation(s)
- B Varriale
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Seconda Università di Napoli, Italy
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Abstract
In Rana esculenta the presence of an androgen receptor in both the male and female Harderian gland (HG) has been demonstrated. Hybridization analysis has evidenced a high degree of homology between the rat androgen receptor cDNA and the frog androgen receptor mRNA (fARmRNA). Correspondingly the molecular size of fARmRNA is similar to those described in mammals (9.4 kb). In in vivo experiments testosterone (T) increases the levels of fARmRNA. The use of the antiandrogen alone or in combination with T prevents the increase of fARmRNA. In the control animals a loss of fARmRNA has been observed. In primary cultures of HG cells, the steady-state levels of fARmRNA increase in the cells exposed to T. These results suggest that T exerts an autoinduction on its own receptor, increasing the levels of fARmRNA. In Xenopus laevis the HG shows a sexual dimorphism of the protein pattern. The female shows two major proteins (210 and 180 kDa). Administration of estradiol to the male shifts the protein pattern into the female one. In this respect an estrogen receptor mRNA (ERmRNA) has been found in the female gland and can be induced in the male one. No ARmRNA has been detected in either sexes. A similar sex dimorphism has been found in Gallus domesticus. The female pattern is characterised by a protein fraction of about 210 kDa, the male one by a protein fraction of about 180 kDa. In 4-day-old chicks no sex differences have been found. An ERmRNA is expressed in the female, while no ARmRNA has been detected in both sexes. Neither AR nor ER mRNAs have been detected in the chick HG. Among mammals the HG or the hamster (Mesocricetus auratus) shows an androgen-dependent sex dimorphism. In in vitro experiments T 10(-12) M induces a onefold increase of ARm-RNA with respect to unexposed cells. This effect reaches its maximum (4.4-fold) when cells are exposed to T 10(-8) M. The size of the hamster ARmRNA is similar to that observed in other mammals (9.5 kb). The above results suggest that in the HG the phenomenon of autoinduction occurs and that there is a relationship between the androgen or estrogen dependence of the HG and the digamety of the species.
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Affiliation(s)
- B Varriale
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Seconda Università di Napoli, Italy
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Chieffi G, Baccari GC, Di Matteo L, d'Istria M, Minucci S, Varriale B. Cell biology of the harderian gland. INTERNATIONAL REVIEW OF CYTOLOGY 1996; 168:1-80. [PMID: 8843648 DOI: 10.1016/s0074-7696(08)60882-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The harderian gland is an orbital gland of the majority of land vertebrates. It is the only orbital gland in anuran amphibians since the lacrimal gland develops later during phylogenesis in some reptilian species. Perhaps because it is not found in man, little interest was paid to this gland until about four decades ago. In recent years, however, the scientific community has shown new interest in analyzing the ontogenetic and morphofunctional aspects of the harderian gland, particularly in rodents, which are the preferred experimental model for physiologists and pathologists. One of the main characteristics of the gland is the extreme variety not only in its morphology, but also in its biochemical properties. This most likely reflects the versatility of functions related to different adaptations of the species considered. The complexity of the harderian gland is further shown in its control by many exogenous and endogenous factors, which vary from species to species. The information gained so far points to the following functions for the gland: (1) lubrication of the eye and nictitating membrane, (2) a site of immune response, particularly in birds, (3) a source of pheromones, (4) a source of saliva in some chelonians, (5) osmoregulation in some reptiles, (6) photoreception in rodents, (7) thermoregulation in some rodents, and (8) a source of growth factors.
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Affiliation(s)
- G Chieffi
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate Filippo Bottazzi, Seconda Università di Napoli, Naples, Italy
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Di Matteo L, Chieffi Baccari G, Chieffi P, Minucci S. The effects of testosterone and estradiol on mast cell number in the harderian gland of the frog, Rana esculenta. Zoolog Sci 1995; 12:457-66. [PMID: 8528017 DOI: 10.2108/zsj.12.457] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Harderian gland (HG) of the frog Rana esculenta contains mast cells in the interstitial tissue. The mast cell number (MCN) is influenced by sex hormones. Gonadectomy in both sexes provoked a decrease in MCN in January, while no effect was observed in September. Sex hormone-replacement therapy gave different results; estradiol treatment in castrated males and females always increased MCN, while testosterone did not. Acute estradiol treatment provoked an increase in MCN on days 2 and 4 of treatment and the morphology of the glandular compartment appeared normal. On days 8, 10 and 12 of treatment the MCN drastically decreased. The majority of glandular acini appeared strongly disorganized and the interstitial tissue became hypertrophic in concomitance with an increased vascularization. Our results suggest that estradiol acts by stimulating mast cells and acute estradiol treatment provokes proliferation of interstitial connective tissue together with glandular cells damage.
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Affiliation(s)
- L Di Matteo
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Napoli, Italy
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Serino I, Monteleone P, d'Istria M. Effects of gonadectomy and temperature on the N-acetyltransferase activity in the harderian gland of the green frog Rana esculenta. Comp Biochem Physiol B Biochem Mol Biol 1995; 110:33-6. [PMID: 7858948 DOI: 10.1016/0305-0491(94)00145-k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Since, in the Harderian gland (HG) of the hamster, the N-acetyltransferase (NAT), the specific enzyme involved in the biosynthesis of melatonin, exhibits a sexual dimorphism, in the present study, we investigated whether such a dimorphism is present also in the HG of the green frog Rana esculenta. In intact frogs, no significant differences emerged between males and females in the HG NAT activity under both cold (10 degrees C) and warm (22 degrees C) temperature conditions. In female frogs, the HG NAT activity was significantly decreased by both gonadectomy (P < 0.001) and warm temperature (P < 0.001), the two effects being not additive. In male animals, neither gonadectomy nor temperature alone significantly affected the activity of the NAT enzyme in the HG. However, gonadectomized male frogs exposed to warm temperature exhibited a significant drop in the HG NAT activity (P < 0.005). These data show that, in Rana esculenta, although no sexual dimorphism exists in the HG NAT activity, a sex difference is evident in the modulation of the enzyme activity by gonads and temperature, the female frogs being more sensitive to the impairing effects of both gonadectomy and higher temperature.
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Affiliation(s)
- I Serino
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate Filippo Bottazzi, Seconda Università degli Studi di Napoli, Italy
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Minucci S, Chieffi Baccari G, Di Matteo L. The effect of sex hormones on lipid content and mast cell number in the harderian gland of the female toad, Bufo viridis. Tissue Cell 1994; 26:797-805. [PMID: 7886670 DOI: 10.1016/0040-8166(94)90031-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Harderian gland of the toad Bufo viridis is a dimorphic gland owing to the presence of lipid droplets in the female glandular cells present only during summer months. Ovariectomy causes the disappearance of sudanophilia and estrogen-treatment completely prevents this change, while testosterone-injection has little effect. Estradiol-treatment also provokes a proliferation of the interstitial connective tissue concomitantly with the mast cell number increase. Our results suggest that estradiol acts, stimulating both mast cell and connective tissue proliferation, and plays a role in determining the expression of the female type of the toad Harderian gland.
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Affiliation(s)
- S Minucci
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate 'F. Bottazzi', Facoltà di Medicina e Chirurgia Seconda Università di Napoli, Italy
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Varriale B, Serino I. The androgen receptor mRNA is up-regulated by testosterone in both the Harderian gland and thumb pad of the frog, Rana esculenta. J Steroid Biochem Mol Biol 1994; 51:259-65. [PMID: 7826887 DOI: 10.1016/0960-0760(94)90038-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Alpha 32P-labelled cDNA probe from plasmid containing rat androgen receptor (rAR) has been tested in hybridization experiments using RNAs from the Harderian gland and thumb pad of the edible frog, Rana esculenta. Northern blot analysis has shown a high degree of homology between the rAR cDNA and the frog androgen receptor mRNA (fAR mRNA); this has been supported by both the hybridization conditions (high stringency) and the molecular size of fAR mRNA which is quite similar to those described in mammals (9.4 kb). The role of androgens has been further investigated with respect to the kinetics of expression of fAR mRNA in in vivo experiments. In both the Harderian gland and thumb pad, testosterone has increased the levels of fAR mRNA as compared with the untreated groups. The use of cyproterone acetate (CPA) in combination with testosterone has resulted in a loss of the increase in fAR mRNA as compared to testosterone-treated groups, while CPA alone has resembled the control group. In primary cultures of frog Harderian gland and thumb pad cells, the steady-state levels of fAR mRNA have been increased in the cells exposed to testosterone as compared to those not exposed. These findings confirm that, in these androgen target tissues, testosterone exerts an up-regulation on its own receptors, increasing the accumulation of fAR mRNA in the same way as oestrogens up-regulate the expression of their own receptors in Xenopus liver and oviduct cells.
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Affiliation(s)
- B Varriale
- Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Facoltà di Medicina e Chirurgia, II Università di Napoli, Italy
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