On the Mechanism of Calcium Secretion in the Avian Shell Gland (Uterus)1

Eastin, William C.; Spaziani, Eugene

doi:10.1095/biolreprod19.3.505

Cited by 67 publications

(34 citation statements)

References 19 publications

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“…It is likely that the supply of Ca and carbonate ions to the lumen of the shell gland are interdependent. In this regard, Pearson et al (1977) suggested that Ca transport across the avian shell gland is related to the activity of CA in this tissue, and Eastin and Spaziani (1978) have reported a dependency of Ca secretion on lumen bicarbonate concentration and bicarbonate production.…”

Section: Resultsmentioning

confidence: 99%

Research Note: Responses of Laying Hens on Saline Drinking Water to Dietary Supplementation with Various Zinc Compounds

Balnave

Zhang

1993

Poultry Science

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Production variables, eggshell defects, eggshell quality, the concentration of calcium-binding protein (CaBP), and the activity of carbonic anhydrase (CA) in the shell gland mucosa were determined in hens receiving town water (10 mg Na/L), or town water supplemented with 2 g NaCl/L (796 mg Na/L). Five treatments were examined. Control hens received town water and a proprietary layer mash containing .17% Na. The remaining four treatments received the water containing NaCl (2 g/L). Hens of Treatment 2 were fed the proprietary layer mash and those of Treatments 3, 4, and 5 received, respectively, the layer mash containing supplements of Zn-methionine (Zinpro-200; .5 g/kg), Zn sulfate (ZnSO4.7H2O; .46 g/kg), or chelated Zn-EDTA (.54 g/kg) to supply the same concentration of Zn (.1 g/kg). The treatments were applied for 6 wk. Hens receiving the saline drinking water without any dietary Zn supplement produced significantly (P < .05) more eggs with shell defects than hens receiving the town water. This increase in the incidence of eggshell defects was associated with significant reductions in eggshell breaking strength, the concentration of CaBP, and the activity of CA. Supplementing the saline drinking water with any of the three Zn compounds significantly reduced the incidence of eggshell defects and in some cases improved shell breaking strength, the concentration of CaBP, and the activity of CA.

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Section: Resultsmentioning

confidence: 99%

Research Note: Responses of Laying Hens on Saline Drinking Water to Dietary Supplementation with Various Zinc Compounds

Balnave

Zhang

1993

Poultry Science

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“…Altered microcirculation and/or a reduced number of capillaries in the exposed birds may therefore reduce the amount of calcium available for shell formation. In addition, impaired transport or reduced concentration of HCO 3 2 ions may also reduce the availability of Ca 2þ since transport of these two ions through the shell gland mucosa is, to some extent, coupled (Pearson & Goldner 1974, Eastin & Spaziani 1978.…”

Section: Discussionmentioning

confidence: 99%

Embryonic exposure to oestrogen causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen

Berg¹,

Blomqvist²,

Holm³

et al. 2004

Reproduction

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Eggshell thinning among wild birds has been an environmental concern for almost half a century. Although the mechanisms for contaminant-induced eggshell thinning are not fully understood, it is generally conceived to originate from exposure of the laying adult female. Here we show that eggshell thinning in the domestic hen is induced by embryonic exposure to the synthetic oestrogen ethynyloestradiol. Previously we reported that exposure of quail embryos to ethynyloestradiol caused histological changes and disrupted localization of carbonic anhydrase in the shell gland in the adult birds, implying a functional disturbance in the shell gland. The objective of this study was to examine whether in ovo exposure to ethynyloestradiol can affect eggshell formation and quality in the domestic hen. When examined at 32 weeks of age, hens exposed to ethynyloestradiol in ovo (20 ng/g egg) produced eggs with thinner eggshells and reduced strength (measured as resistance to deformation) compared with the controls. These changes remained 14 weeks later, confirming a persistent lesion. Ethynyloestradiol also caused a decrease in the number of shell gland capillaries and in the frequency of shell gland capillaries with carbonic anhydrase activity. These data suggested that a disrupted carbonic anhydrase expression was involved in the mechanism for the oestrogen-induced eggshell thinning found in this study. The results support our hypothesis that eggshell thinning in avian wildlife can result from a structural and functional malformation in the shell gland, induced by xeno-oestrogen exposure during embryonic development.

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“…The major chemical component of the eggshell is calcium carbonate (97% by mass). The avian shell gland is responsible for the secretion of Ca 2+ and HCO 3 -that combine within the shell gland lumen to form calcium carbonate or calcite (Eastin and Spaziani, 1978b) . Presently, the mechanisms and regulation of monovalent ion absorption and secretion by the shell gland epithelium have not been characterized.…”

mentioning

confidence: 99%

“…Previous studies of Na + transport in vivo have demonstrated net absorption when the shell gland was perfused with plasmalike saline solution (Eastin and Spaziani, 1978b). Addition of ouabain, an inhibitor of Na + -K + ATPase activity, inhibited basal Na + transport.…”

mentioning

confidence: 99%