Effects of hypophysectomy and prolactin on the sodium balance of Tilapia mossambica in fresh water

Dharmamba, Muthusamy; Maetz, J.

doi:10.1016/0016-6480(72)90018-4

Cited by 75 publications

(26 citation statements)

References 22 publications

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“…In many teleost species these losses are controlled by pro lactin (Hirano, 1986). The hormone reduces the branchial permeability to water and ions, including Na+, as has been demon strated in killifish and tilapia (Potts and Fleming, 1971;Dharmamba and Maetz, 1972). We conclude therefore that the high prolactin secretion rate observed in chron ically acid-stressed tilapia is causally con nected with the effective reduction of the branchial Na^ efflux in these fish.…”

Section: Prolactin and N A+ Effluxsupporting

confidence: 65%

“…To minimize stress, fish were placed in the experi mental containers 24 hr (Dharmamba and Maetz, 1972) before addition of 24Na to the exposure system; during this period of acclimation, water was recycled from a 200-liter volume. After closing the system the experiment was started by the injection of 24Na into the water; a volume of 400 ml water was recirculated.…”

Section: Analytical Proceduresmentioning

confidence: 99%

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Prolactin cell activity and sodium fluxes in tilapia (Oreochromis mossambicus) after long-term acclimation to acid water

Flik¹,

Velden²,

Seegers³

et al. 1989

General and Comparative Endocrinology

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Please be advised that this information was generated on 2018-05-12 and may be subject to change.,f NERAL AND COMPARATIVE ENDOCRINOLOGY 75, 3 9^5 (1989) Prolactin Cell Activity and Sodium Fluxes in Tilapia (Oreochromis mossambicus) after Long-Term Acclimation to Acid Water G e r t F l i k ,* J o a n A. v a n d e r V e l d e n , ! H e in C. In tilapia exposed for 3 months to water of pH 4.5, prolactin cell activity, as estimated by ultrastructural morphometry and determination of prolactin synthesis in vitro, was signifi cantly higher than in controls from neutral water. Sodium influx from the water was 50% lower than in the controls, indicating impaired branchial sodium uptake mechanisms. In contrast to predictions based on the results of short-term exposure to acid water-which is known to induce an increase of sodium efflux-the sodium efflux rate was reduced to 70% of the control value. It is concluded that tilapia are able to acclimate to acid water by successful control-probably via prolactin-of diffusional sodium losses across the integu ment, in particular the gill surface. This compensates for the impaired sodium uptake, and enables the fish to reestablish a positive sodium balance in acid water.

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Section: Prolactin and N A+ Effluxsupporting

confidence: 65%

Section: Analytical Proceduresmentioning

confidence: 99%

Prolactin cell activity and sodium fluxes in tilapia (Oreochromis mossambicus) after long-term acclimation to acid water

Flik¹,

Velden²,

Seegers³

et al. 1989

General and Comparative Endocrinology

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show abstract

“…The sodium intake in the control fish was comparable to that found by Dharmamba & Maetz (1972) in 16-24 g tilapia (15 (imol h " 1100 g_I) but somewhat lower than that reported by us for small tilapia (around 6 g; 45 pmol h~ 100 g-1; Flik et a l, 19896). We ascribe this difference to the larger size (around 200 g) of the fish used in the experiments described here.…”

Section: Discussion Blood and Blood Plasma Analysessupporting

confidence: 69%

Prolactin cell activity and ion regulation in tilapia, Oreochromis mossambicus (Peters): effects of a low magnesium diet

Velden

Flik

Bonga

1992

Journal of Fish Biology

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Freshwater tilapia feeding on a diet containing ] mmol k g '1 magnesium (control diet: 30 mmol kg ' ') grow although at a decreased rate. The diet does not noticeably affect the blood ionic composition. Prolactin cell activity increases in these fish as judged from ¡he enhanced rate ofsynthesis o f 3H-leucine labelled prolactins;« vitro and the ultrastructure o f the cells. N a+ intake and N a+ loss decreases, and chloride cell density increases, phenomena typical for enhanced prolactin cell activity in tilapia. We conclude that tilapia manage to cope with a dietary magnesium insufficiency and suggest that prolactin is involved in the acclimation to this diet.

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“…In tilapia, PRL has been shown to be essential for the survival in fresh water of hypophysectomized fish (Dharmamba et al 1967). Among other osmoregulatory actions, PRL is known to reduce Na + efflux and water permeability at the level of the gill (Dharmamba & Maetz 1972, Dharmamba et al 1976, Wendelaar Bonga & Van der Meij 1981. In addition to its osmoregulatory actions, PRL has been shown to act on other physiological functions, including stimulation of the dermal mucocyte frequency (Flik et al 1994), pigment dispersion in the tegumentary chromatophores (Kitta et al 1993), modulation of testosterone production in the testes (Rubin & Specker 1992), as well as hypercalcemic and corticotrophic effects (Flik et al 1994) and somatotropic actions (Shepherd et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Expression of the prolactin receptor (tiPRL-R) gene in tilapia Oreochromis niloticus: tissue distribution and cellular localization in osmoregulatory organs

Sandra¹,

Rouzic²,

Cauty³

et al. 2000

Journal of Molecular Endocrinology

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The expression of the prolactin receptor (PRL-R) gene has been investigated in various tissues of tilapia (Oreochromis niloticus) reared in fresh or brackish water. Using a cDNA probe spanning the extracellular domain of the tilapia PRL-R and Northern blot analysis, the presence of tilapia PRL-R mRNA has been confirmed in the osmoregulatory organs and has been detected in other tissues, including the skin, the brain, the reproductive organs, and the two major hematopoietic organs (spleen and head kidney), as well as circulating lymphocytes. These findings suggest a conservation of the physiological processes regulated by prolactin throughout the vertebrates, including immunity and central nervous activity. A non-radioactive in situ hybridization procedure has allowed us to detect the expression of the tilapia PRL-R in the branchial chloride cells and the intestinal mucosal layer of fresh water animals, confirming the direct control exerted by prolactin on the water and ionic exchanges in tilapia. In all the tissues examined one unique PRL-R transcript has been detected with a similar size (3·2 kb) whatever the salinity conditions. Thus, the transcriptional expression of the tilapia PRL-R strongly differs from the complex RNA pattern reported for the higher vertebrates PRL-R and provides an additional argument for the existence of a single PRL-R for both prolactin isoforms in this fish species.

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Effects of hypophysectomy and prolactin on the sodium balance of Tilapia mossambica in fresh water

Cited by 75 publications

References 22 publications

Prolactin cell activity and sodium fluxes in tilapia (Oreochromis mossambicus) after long-term acclimation to acid water

Prolactin cell activity and sodium fluxes in tilapia (Oreochromis mossambicus) after long-term acclimation to acid water

Prolactin cell activity and ion regulation in tilapia, Oreochromis mossambicus (Peters): effects of a low magnesium diet

Expression of the prolactin receptor (tiPRL-R) gene in tilapia Oreochromis niloticus: tissue distribution and cellular localization in osmoregulatory organs

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