Salmon calcitonin inhibits whole body Ca2+ uptake in young rainbow trout

Wagner, Graham F.; Jaworski, EM; Radman, DP

doi:10.1677/joe.0.1550459

Cited by 28 publications

(22 citation statements)

References 34 publications

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“…The hypocalcaemic factors include stanniocalcin which was originally isolated, characterised and its biological activity determined in fish (for review see Wendelaar Bonga & Pang 1991, Wagner et al 1998 and calcitonin which has hypocalcaemic effects in goldfish (Sasayama et al 1993) and salmonids (Wagner et al 1997). The principal hypercalcaemic factor identified in tetrapods, parathyroid hormone (PTH), has not been identified in fish.…”

Section: Discussionmentioning

confidence: 99%

Calcium balance in sea bream (Sparus aurata): the effect of oestradiol-17beta

Guerreiro

Fuentes

Canário³

et al. 2002

Journal of Endocrinology

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In all teleost fishes vitellogenesis is triggered and maintained by oestradiol-17 (E 2 ) and is accompanied by an increase of blood plasma calcium and phosphate. The action of this hormone on calcium metabolism was investigated by treating fast-growing immature juvenile sea bream (Sparus aurata) with coconut butter implants alone (control) or implants containing 10 µg/g E 2 . Treatment with E 2 induced the production of circulating vitellogenin, a 2·5-fold increase in plasma ionic Ca 2+ and a 10-fold increase in plasma total calcium, largely bound to protein.In contrast to freshwater species, which obtain most of their calcium from the environment directly through the gills, the intestinal component of calcium uptake of the salt water-living sea bream represented up to 60-70% of the total uptake. The whole body calcium uptake, expressed as the sum of calcium obtained via intestinal and extra-intestinal (likely branchial) routes increased significantly in response to E 2 . Combined influx and unchanged efflux rates resulted in a significant 31% increase in net calcium uptake. There was no evidence for an effect of E 2 on the calcium and phosphate content of the scales or the tartrate-resistant acid phosphatase activity (an index for bone/scale osteoclast activity). While most freshwater fish appear to rely on internal stores of calcium, i.e. bone and/or scales to increase calcium availability, the marine sea bream accommodates calcium-transporting mechanisms to obtain calcium from the environment and preserve internal stores. These observations suggest that a fundamental difference may exist in the E 2 -dependent calcium regulation between freshwater and marine teleosts.

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Section: Discussionmentioning

confidence: 99%

Calcium balance in sea bream (Sparus aurata): the effect of oestradiol-17beta

Guerreiro

Fuentes

Canário³

et al. 2002

Journal of Endocrinology

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“…In teleostean fish, CT has been suggested to be hypocalcemic, but it has also been reported to show a hypercalcemic effect in some cases. (12) CT was found to inhibit gill Ca 2þ uptake (13,14) and could be stimulated by treatment with high-calcium solution. (15,16) On the other hand, CT administration can produce hypercalcemia concomitant with the increase in CT plasma levels.…”

Section: J Jbmrmentioning

confidence: 99%

Involvement of calcitonin and its receptor in the control of calcium-regulating genes and calcium homeostasis in zebrafish (Danio rerio)

Lafont

Wang

Chen

et al. 2010

Journal of Bone and Mineral Research

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Calcitonin (CT) is one of the hormones involved in vertebrate calcium regulation. It has been proposed to act as a hypocalcemic factor, but the regulatory pathways remain to be clarified. We investigated the CT/calcitonin gene-related peptide (CGRP) family in zebrafish and its potential involvement in calcium homeostasis. We identified the presence of four receptors: CTR, CRLR1, CRLR2, and CRLR3. From the phylogenetic analysis, together with the effect observed after CT and CGRP overexpression, we concluded that CTR appears to be a CT receptor and CRLR1 a CGRP receptor. The distribution of these two receptors shows a major presence in the central nervous system and in tissues involved in ionoregulation. Zebrafish embryos kept in high-Ca 2þ -concentration medium showed upregulation of CT and CTR expression and downregulation of the epithelial calcium channel (ECaC). Embryos injected with CT morpholino (CALC MO) incubated in high-Ca 2þ medium, showed downregulation of CTR together with upregulation on ECaC mRNA expression. In contrast, overexpression of CT cRNA induced the downregulation of ECaC mRNA synthesis, concomitant with the downregulation in the calcium content after 30 hours postfertilization. At 4 days postfertilization, CT cRNA injection induced upregulation of hypercalcemic factors, with subsequent increase in the calcium content. These results suggest that CT acts as a hypocalcemic factor in calcium regulation, probably through inhibition of ECaC synthesis. ß

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“…This conflict regarding the effect of CT in fishes has led some workers to suggest that CT is involved either with osmotic regulation (Yamauchi et al 1978), sex-related phenomenon (Yamane & Yamada 1977, Suzuki 2005, skeletal protection during periods of high calcium demands (Wendelaar Bonga & Pang 1991) and to protect scales from excess degradation of calcium at vitellogenesis (Suzuki et al 2000). CT has also been suggested to control dietary calcium uptake (Suzuki et al 1999) and inhibit calcium transport in fish gills (Wagner et al 1997, Mukherjee et al 2004. As yet no definite functions of CT (Hirsch et al 2001, Clark et al 2002, Miller 2006, Nag et al 2007) have been established and more work is necessary to establish its functions in fishes.…”

Section: Introductionmentioning

confidence: 99%

Ultimobranchial gland of freshwater catfish, Heteropneustes fossilis, in response to calcitonin administration

et al. 2009

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The absence o!!f a hypocalcemic effect of calcitonin (CT) in fishes has been suggested due to exceedingly high plasma levels of CT; the fish may be saturated with respect of circulating CT and therefore unable to respond to exogenously administered CT. Earlier it has been suggested that a hypocalcemic action of injected CT may be obscured by changes in the release of endogenous CT and other calcium regulating hormones. In this study we have used artificial freshwater, calcium-deficient freshwater and calcium-rich freshwater and injected the fish with CT. The aim behind selecting these media were (i) in calcium-deficient medium there would be reduced circulating levels of CT, (ii) in calciumrich medium there would be diminished secretion of prolactin (this hormone is hypercalcemic in fish), and (iii) by keeping the fish in calcium-rich medium we can test the antihypercalcemic action of CT. Moreover, the present study would reveal the changes in the ultimobranchial gland (UBG) after keeping the fish in all the above three media and/or injecting the fish with CT. Freshwater catfish, Heteropneustes fossilis, were administered intraperitoneally daily with vehicle or 0.5 U/100g body wt of salmon calcitonin (CT) and kept in artificial freshwater, calcium-rich freshwater and calcium-deficient freshwater for 10 days. Blood samples were collected on 1, 3, 5, and 10 days following the treatment and analyzed for serum calcium levels. The ultimobranchial gland (UBG) was also fixed for histological studies on these intervals. In artificial freshwater there was no change in the serum calcium levels of calcitonin-injected fish. The ultimobranchial gland of calcitonin-injected fish exhibited a progressive decrease in the nuclear volume from day 5 onwards. On day 10 vacuolization in the gland was also noticed. In vehicle-injected fish (control) kept in calcium-rich freshwater hypercalcemia has been noticed which persists till the end of the experiment. In calcitonin-treated fish maintained in calcium-rich freshwater there is no change in serum calcium level as compared to vehicle-injected fish. In vehicleinjected fish the UBG depicts decreased staining response and increased nuclear volume at day 5. On day 10 the nuclear volume is further increased and few degenerating cells have been noticed. Calcitonin fails to induce any histological change in the UBG as compared to control. In vehicle-injected fish kept in calcium-deficient freshwater the serum calcium levels decrease from day 1 to day 3. The levels exhibit hypercalcemia on day 10. CT treatment to the fish kept in calcium-deficient freshwater evokes a decrease in the calcium levels on day 1 and day 3. A significant hypercalcemia has been noticed on day 5 and day 10. In vehicle-injected fish kept in calcium-deficient freshwater the UBG reveals a decreased staining response on day 10. In CT-injected fish maintained in calcium-deficient freshwater the UBG depicts an increased nuclear volume and few exhausted cells on day 10. It can be concluded that CT can provoke hypocalcemia o...

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Salmon calcitonin inhibits whole body Ca2+ uptake in young rainbow trout

Cited by 28 publications

References 34 publications

Calcium balance in sea bream (Sparus aurata): the effect of oestradiol-17beta

Calcium balance in sea bream (Sparus aurata): the effect of oestradiol-17beta

Involvement of calcitonin and its receptor in the control of calcium-regulating genes and calcium homeostasis in zebrafish (Danio rerio)

Ultimobranchial gland of freshwater catfish, Heteropneustes fossilis, in response to calcitonin administration

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