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Carmen Osuna - One of the best experts on this subject based on the ideXlab platform.
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thyroxine type ii 5 deiodinase activity in pineal and Harderian Gland is enhanced by hypothyroidism but is independent of serum thyroxine concentrations during hyperthyroidism
International Journal of Biochemistry, 1993Co-Authors: Carmen Osuna, Amalia Rubio, Jose M Orta, Patrocinio Molinero, Juan M. GuerreroAbstract:Abstract 1. 1. This paper studies the effect of thyroid status on 5'- d activity in pineal Gland, Harderian Gland, brown adipose tissue (BAT), pituitary Gland, brain frontal cortex (BFC), and cerebellum. 2. 2. Hypothyroidism clearly increased diurnal 5'- d activity in Harderian Gland, BAT, pituitary Gland, BFC, and cerebellum. In pineal Gland, diurnal values of 5'- d activity were not affected by hypothyroidism. 3. 3. Hypothyroidism in adult rats clearly enhanced nocturnal increase of 5'- d activity in pineal and Harderian Gland. Congenital hypothyroidism also enhanced the nocturnal increase of 5'- d activity in pineal Gland. 4. 4. Hyperthyroidism inhibited 5'- d activity in pituitary Gland, BFC, and cerebellum. A small inhibition, although significant, was found in BAT. 5. 5. In pineal and Harderian Gland, hyperthyroidism did not inhibit either the basal diurnal values of the enzyme or the nocturnal increase of its activity. 6. 6. Results suggest that, in tissues where 5' d -activity is regulated by adrenergic mechanisms, mostly pineal Gland and Harderian Gland, the enzyme activity is independent of serum T4 concentrations during hyperthyroidism.
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β- and α-adrenergic receptors are involved in regulating type II thyroxine 5′-deiodinase activity in the rat Harderian Gland
Life sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A. Lopez-gonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
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β and α adrenergic receptors are involved in regulating type ii thyroxine 5 deiodinase activity in the rat Harderian Gland
Life Sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A Lopezgonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
Amalia Rubio - One of the best experts on this subject based on the ideXlab platform.
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thyroxine type ii 5 deiodinase activity in pineal and Harderian Gland is enhanced by hypothyroidism but is independent of serum thyroxine concentrations during hyperthyroidism
International Journal of Biochemistry, 1993Co-Authors: Carmen Osuna, Amalia Rubio, Jose M Orta, Patrocinio Molinero, Juan M. GuerreroAbstract:Abstract 1. 1. This paper studies the effect of thyroid status on 5'- d activity in pineal Gland, Harderian Gland, brown adipose tissue (BAT), pituitary Gland, brain frontal cortex (BFC), and cerebellum. 2. 2. Hypothyroidism clearly increased diurnal 5'- d activity in Harderian Gland, BAT, pituitary Gland, BFC, and cerebellum. In pineal Gland, diurnal values of 5'- d activity were not affected by hypothyroidism. 3. 3. Hypothyroidism in adult rats clearly enhanced nocturnal increase of 5'- d activity in pineal and Harderian Gland. Congenital hypothyroidism also enhanced the nocturnal increase of 5'- d activity in pineal Gland. 4. 4. Hyperthyroidism inhibited 5'- d activity in pituitary Gland, BFC, and cerebellum. A small inhibition, although significant, was found in BAT. 5. 5. In pineal and Harderian Gland, hyperthyroidism did not inhibit either the basal diurnal values of the enzyme or the nocturnal increase of its activity. 6. 6. Results suggest that, in tissues where 5' d -activity is regulated by adrenergic mechanisms, mostly pineal Gland and Harderian Gland, the enzyme activity is independent of serum T4 concentrations during hyperthyroidism.
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β- and α-adrenergic receptors are involved in regulating type II thyroxine 5′-deiodinase activity in the rat Harderian Gland
Life sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A. Lopez-gonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
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β and α adrenergic receptors are involved in regulating type ii thyroxine 5 deiodinase activity in the rat Harderian Gland
Life Sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A Lopezgonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
Susan J. Rehorek - One of the best experts on this subject based on the ideXlab platform.
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The Harderian Gland of two species of skink (Tiliqua rugosa and Hemiergis decresiensis): a discussion of the significance of lymphatic tissue in the squamate Harderian Gland
Canadian Journal of Zoology, 2006Co-Authors: Susan J. Rehorek, Jeremy J. Bakerj.j. Baker, Mark N. Hutchinsonm.n. Hutchinson, Bruce T. FirthAbstract:The Harderian Gland is an orbital structure ubiquitous in reptiles. Numerous functions have been ascribed to this Gland, including osmoregulation, chemoreception, and immunity. The anatomical, histological, histochemical, and ultrastructural characteristics of the Harderian Gland of two species of skink, Tiliqua rugosa (Gray, 1825) and Hemiergis decresiensis (Cuvier, 1829), were examined. Mucous and serous secretory cells were observed in both species. In T. rugosa, mucous cells are located in a small anterior region, while serous cells occupy most of the Gland. In contrast, the Harderian Gland of H. decresiensis contains mainly serous cells, with a few anteriorly located mucous cells. In both species, the serous granules exhibit internal compartmentalization. There is no evidence of either lipid secretions or salt secreting cells. However, there were either a few plasma cells (H. decresiensis) or several lymphatic aggregations (T. rugosa) in the serous portion of the Gland. The presence of such lymphatic...
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The primate Harderian Gland: Does it really exist?
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft, 2006Co-Authors: Susan J. Rehorek, Timothy D. SmithAbstract:The Harderian Gland, an anterior orbital structure, is either absent or vestigial in primates. This is based upon gross anatomical observations of scattered adult specimens. Though largely absent in the adult human, it is present in the fetal and neonatal stages. Thus, histological examination of the orbital region of neonatal material was undertaken in other primates. The orbital region of neonatal specimens of 12 species of strepsirrhines (Lemuriformes and Lorisiformes), and haplorhine (tarsiers and callitrichids) was examined. The Harderian Gland is ensconced in either periorbital fat or connective tissue and thus was not readily identifiable gross anatomically. Thus, it may have been missed in the anatomical studies. Tarsal Glands are present in all neonatal primate eyelids. The relative size of the neonatal primate Harderian Gland can be subdivided into five separate categories, ranging from large to absent (tarsiers), with no apparent phylogenetic trends. Thus, the Harderian Gland is present in numerous primates at birth, quite possibly all strepsirrhines. The positive findings on callitrichids question whether any anthropoids lack the Harderian Gland postnatally. The enigmatic tarsier appears to possess another apomorphic trait in lacking a Harderian Gland. Further study is required to determine the role of this Gland and its relationship with the tarsal Glands.
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The Harderian Gland of two species of snakes: Pseudonaja textilis (Elapidae) and Thamnophis sirtalis (Colubridae)
Canadian Journal of Zoology, 2003Co-Authors: Susan J. Rehorek, Bruce T. Firth, Mimi Halpern, Mark N. HutchinsonAbstract:The reptilian Harderian Gland is a poorly understood cephalic structure. Despite the recent assertion that in snakes it may function as part of the vomeronasal system, the Harderian Gland has been described in few snake species. In this study we examined the gross anatomy, histology, and ultrastructure of the Harderian Gland of two different advanced snake species (Colubroidea): Pseudonaja textilis (Elapidae) and Thamnophis sirtalis (Colubridae). In both species the Harderian Gland is a large serous Gland whose secretions pass directly into the vomeronasal organ via the nasolacrimal duct. Contrary to previous publications, the Harderian Gland in both species studied possesses a specific duct system lined by mucous cells. However, the Harderian Glands of these two species differ in shape, the histochemical nature of these mucous secretions, and the ultrastructure of the serous granules. In conclusion, though the Harderian Glands of snakes are remarkably conserved morphologically, there is some interspecifi...
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The Harderian Gland of two species of snakes: Pseudonaja textilis (Elapidae) and Thamnophis sirtalis (Colubridae)
Canadian Journal of Zoology, 2003Co-Authors: Susan J. Rehorek, Bruce T. Firth, Mimi Halpern, Mark N. HutchinsonAbstract:The reptilian Harderian Gland is a poorly understood cephalic structure. Despite the recent assertion that in snakes it may function as part of the vomeronasal system, the Harderian Gland has been ...
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Can an orbital Gland function in the vomeronasal sense? A study of the pygopodid Harderian Gland
Canadian Journal of Zoology, 2000Co-Authors: Susan J. Rehorek, Bruce T. Firth, Mark N. HutchinsonAbstract:The Harderian Gland occurs in the orbit of most tetrapod vertebrates. A growing body of evidence suggests that this Gland is associated with the chemoreceptive function of the vomeronasal organ. In the present study, the mor - phology of the Harderian Gland in two species of pygopodids was examined, and the results were contrasted with those from both geckos and snakes. The results show that the pygopodid Harderian Gland shares histochemical and ultrastructural features with that of the geckos. However, in several gross morphological features, the pygopodid Harderian Gland more closely resemble that of snakes than that of geckos. In both pygopodids and snakes, the nasolacrimal duct forms a direct link between the Harderian Gland and the vomeronasal organ, which indicates that this specialized connection between the Harderian Gland and vomeronasal organ is a convergent evolutionary attribute of these two groups.
Juan M. Guerrero - One of the best experts on this subject based on the ideXlab platform.
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thyroxine type ii 5 deiodinase activity in pineal and Harderian Gland is enhanced by hypothyroidism but is independent of serum thyroxine concentrations during hyperthyroidism
International Journal of Biochemistry, 1993Co-Authors: Carmen Osuna, Amalia Rubio, Jose M Orta, Patrocinio Molinero, Juan M. GuerreroAbstract:Abstract 1. 1. This paper studies the effect of thyroid status on 5'- d activity in pineal Gland, Harderian Gland, brown adipose tissue (BAT), pituitary Gland, brain frontal cortex (BFC), and cerebellum. 2. 2. Hypothyroidism clearly increased diurnal 5'- d activity in Harderian Gland, BAT, pituitary Gland, BFC, and cerebellum. In pineal Gland, diurnal values of 5'- d activity were not affected by hypothyroidism. 3. 3. Hypothyroidism in adult rats clearly enhanced nocturnal increase of 5'- d activity in pineal and Harderian Gland. Congenital hypothyroidism also enhanced the nocturnal increase of 5'- d activity in pineal Gland. 4. 4. Hyperthyroidism inhibited 5'- d activity in pituitary Gland, BFC, and cerebellum. A small inhibition, although significant, was found in BAT. 5. 5. In pineal and Harderian Gland, hyperthyroidism did not inhibit either the basal diurnal values of the enzyme or the nocturnal increase of its activity. 6. 6. Results suggest that, in tissues where 5' d -activity is regulated by adrenergic mechanisms, mostly pineal Gland and Harderian Gland, the enzyme activity is independent of serum T4 concentrations during hyperthyroidism.
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β- and α-adrenergic receptors are involved in regulating type II thyroxine 5′-deiodinase activity in the rat Harderian Gland
Life sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A. Lopez-gonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
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β and α adrenergic receptors are involved in regulating type ii thyroxine 5 deiodinase activity in the rat Harderian Gland
Life Sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A Lopezgonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
M. A. Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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β- and α-adrenergic receptors are involved in regulating type II thyroxine 5′-deiodinase activity in the rat Harderian Gland
Life sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A. Lopez-gonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
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β and α adrenergic receptors are involved in regulating type ii thyroxine 5 deiodinase activity in the rat Harderian Gland
Life Sciences, 1991Co-Authors: Amalia Rubio, Juan M. Guerrero, M. A. Gonzalez, Miguel A Lopezgonzalez, Carmen OsunaAbstract:The role of alpha- and beta-adrenergic receptors in regulation of rat Harderian Gland type II thyroxine 5'-deiodinase (5'-D) activity was investigated. Our results show that isoproterenol, a beta-adrenergic agonist, and phenylephrine, an alpha-adrenergic agonist, elicited increases in Harderian Gland 5'-D activity. The activation was dependent on the time and the dose of the drug. Other adrenergic agonists, i.e., norepinephrine, methoxamine or terbutaline, also clearly increased the enzyme activity. Moreover, administration of propranolol, a beta-adrenergic blocker, or prazosin, an alpha-adrenergic blocker, completely prevented the activation of the enzyme induced by norepinephrine. Results show a clear regulation by adrenergic mechanisms of 5'-D activity in the rat Harderian Gland, where alpha- and beta-adrenergic receptors appear to be involved.
