Do thyroid and testis modulate the effects of pineal and melatonin on haemopoietic variables inClarias batrachus?

Shedpure, Maya

doi:10.1007/bf02704721

Cited by 10 publications

(5 citation statements)

References 24 publications

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“…It has been reported that at least 25% of the total fatty acids identified in the rat pineal lipids are represented by arachidonic acid (20:4n-6) and 22:6n-3 [23,24]. The mammalian pineal gland is a prominent secretory organ that synthesizes and releases a number of exocrine and endocrine substances [25]. Melatonin, an indoleamine hormone, is synthesized in the pineal gland from tryptophan and secreted for circulation.…”

Section: Polyunsaturated Fatty Acids and The Pin-eal Glandmentioning

confidence: 99%

The Ability of Melatonin to Counteract Lipid Peroxidation in Biological Membranes

Catalá

2007

CMM

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This paper reviews recent data relevant to the antioxidant effects of melatonin with special emphasis on the changes produced in polyunsaturated fatty acids located in the phospholipids of biological membranes. The onset of lipid peroxidation within cellular membranes is associated with changes in their physicochemical properties and with the impairment of protein functions located in the membrane environment. All cellular membranes are especially vulnerable to oxidation due to their high concentration of polyunsaturated fatty acids. These processes combine to produce changes in the biophysical properties of membranes that can have profound effects on the activity of membrane-bound proteins. This review deals with aspects for lipid peroxidation of biological membranes in general, but with some emphasis on changes of polyunsaturated fatty acids, which arise most prominently in membranes and have been studied extensively in our laboratory. The article provides current information on the effect of melatonin on biological membranes, changes in fluidity, fatty acid composition and lipid-protein modifications during the lipid peroxidation process of photoreceptor membranes and modulation of gene expression by the hormone and its preventive effects on adriamycin-induced lipid peroxidation in rat liver. Simple model systems have often been employed to measure the activity of antioxidants. Although such studies are important and essential to understand the mechanisms and kinetics of antioxidant action, it should be noted that the results of simple in vitro model experiments cannot be directly extrapolated to in vivo systems. For example, the antioxidant capacity of melatonin, one of the important physiological lipophilic antioxidants, in solution of pure triglycerides enriched in omega-3 polyunsaturated fatty acids is considerably different from that in subcellular membranes.

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Section: Polyunsaturated Fatty Acids and The Pin-eal Glandmentioning

confidence: 99%

The Ability of Melatonin to Counteract Lipid Peroxidation in Biological Membranes

Catalá

2007

CMM

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“…In rainbow trout, i.p.‐injected ipodate at 5 mg/100 g depressed plasma T 3 levels, T 4 monodeiodination and plasma clearance of both T 4 and T 3 [243], and reduced the hepatic nuclear T 3 receptor maximum binding capacity [229]. Iopanoic acid also has been used to induce a hypothyroid state in brown trout [244] and C. batrachus [245].…”

Section: Studies Of Thyroid Disruptionmentioning

confidence: 99%

Contaminant effects on the teleost fish thyroid

Brown

Adams

Cyr

et al. 2004

Enviro Toxic and Chemistry

227

139

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Abstract-Numerous environmentally relevant chemicals, including polychlorinated hydrocarbons, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated paraffins, organophosphorous pesticides, carbamate pesticides, cyanide compounds, methyl bromide, phenols, ammonia, metals, acid loads, sex steroids, and pharmaceuticals, exert acute or chronic effects on the thyroid cascade in the approximately 40 teleost fish species tested to date. Thyroid endpoints, therefore, serve as biomarkers of exposure to environmental pollutants. However, the mechanisms underlying thyroid changes and their physiological consequences are poorly understood because the thyroid cascade may respond indirectly and it has considerable capacity to compensate for abuses that otherwise would disrupt thyroid hormone homeostasis. Indeed, a xenobiotic-induced change in fish thyroid function has yet to be conclusively causally linked to decreased fitness or survival. Other complications in interpretation arise from the diversity of test conditions employed and the often indiscriminate use of numerous thyroid endpoints. Future work should be directed toward standardizing test conditions and thyroid endpoints and investigating causal links between thyroid changes and fish growth, reproduction, and development. Development may be particularly susceptible to thyroid disruption, and thyroid endpoints appropriate for early life stages need to be applied.

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“…The retina and pineal gland probably arose via divergence from a common ancestral photoreceptive organ, and consistently, the pineal gland acts as a photosensory organ in the lowest vertebrate (1)(2)(3). In the course of vertebrate evolution, the physiological role of the pineal gland has been changed from a photosensory organ to a photoendocrinal organ in the lower vertebrates and eventually to a neuroendocrinal organ in mammals (4,5). Generally, the retina receives visual images and transmits them to the brain, whereas the primary role of the pineal gland is the rhythmic production of circulating melatonin, which regulates numerous physiological activities (6).…”

mentioning

confidence: 99%

Pineal expression-promoting element (PIPE), a cis- acting element, directs pineal-specific gene expression in zebrafish

Asaoka

Mano

Kojima

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The pineal gland, sharing morphological and biochemical similarities with the retina, plays a unique and central role in the photoneuroendocrine system. The unique development of the pineal gland is directed by a specific combination of the expressed genes, but little is known about the regulatory mechanism underlying the pineal-specific gene expression. We isolated a 1.1-kbp fragment upstream of the zebrafish exo-rhodopsin (exorh) gene, which is expressed specifically in the pineal gland. Transgenic analysis using an enhanced green fluorescent protein reporter gene demonstrated that the proximal 147-bp region of the exorh promoter is sufficient to direct pineal-specific expression. This region contains three copies of a putative cone rod homeobox (Crx)͞Otx-binding site, which is known to be required for expression of both retina-and pineal-specific genes. Deletion and mutational analyses of the exorh promoter revealed that a previously uncharacterized sequence TGACCCCAATCT termed pineal expression-promoting element (PIPE) is required for pineal-specific promoter activity in addition to the Crx͞Otx-binding sites. By using the zebrafish rhodopsin (rh) promoter that drives retina-specific expression, we created a reporter construct having ectopic PIPE in the rh promoter at a position equivalent to that in the exorh promoter by introducing five nucleotide changes. Such a slight modification in the rh promoter induced ectopic enhanced green fluorescent protein expression in the pineal gland without affecting its retinal expression. These results identify PIPE as a critical cis-element contributing to the pineal-specific gene expression, in combination with the Crx͞Otx-binding site(s).

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Do thyroid and testis modulate the effects of pineal and melatonin on haemopoietic variables inClarias batrachus?

Cited by 10 publications

References 24 publications

The Ability of Melatonin to Counteract Lipid Peroxidation in Biological Membranes

The Ability of Melatonin to Counteract Lipid Peroxidation in Biological Membranes

Contaminant effects on the teleost fish thyroid

Pineal expression-promoting element (PIPE), a cis- acting element, directs pineal-specific gene expression in zebrafish

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