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

Sodium and anion transport across the avian uterine (shell gland)epithelium

“…One possible reason for this increase in Na + absorption may be to reduce fluid volume within the shell gland lumen and to recover the Na + and Cl -that were transported across the epithelium during shell deposition. This interpretation is consistent with earlier results from in situ perfused shell gland experiments where net decreases in luminal Na + and Cl -concentrations were observed (Eastin and Spaziani, 1978a). Moreover, previous studies of Na + -K + ATPase expression in chicken shell gland showed that mRNA levels of the α1 subunit varied depending on the stage of shell formation and exhibited different expression patterns within the surface pseudostratified epithelium and the glandular epithelium (Lavelin et al, 2001).…”

“…Significant defects in shell integrity often result in death of the developing embryo (Bennett, 1992). Factors that influence the structure and composition of the eggshell include: calcium (Ca 2+ ) secretion, bicarbonate (HCO 3 -) secretion, protein content, vitamin D, vitamin C, phosphorus and various fatty acids (Eastin and Spaziani, 1978a). The major chemical component of the eggshell is calcium carbonate (97% by mass).…”

Calcitonin Receptor Binding Properties in Bone and Kidney of the Chicken During the Oviposition Cycle

“…The ICa concentration of the blood plasma was at a low level during the period from 13 to 6 h before oviposition, attributable to a large amount of consumption of ICa for the egg shell formation. (22,(41)(42)(43) The increase in the ICa concentration is recognized at 3 h before oviposition (Table 1) and CT receptors of the calvaria and the kidney in the laying hen. Increases of binding affinity of both PTH and CT receptors may implicate a relatively rapid turnover of the calcium metabolism in the bone and kidney during the egg shell formation.…”

Influence of chlorinated hydrocarbons, Hg2+ and methyl-Hg+ on steroid hormone receptors from eggshell gland mucosa of domestic fowls and ducks

“…The role of different steroid hormones in eggshell calcification is not fully clarified (Eastin and Spaziani 1978). With regard to the whole avian oviduct, estrogen is mainly responsible for growth and differentiation, whereas progesterone, as a secretory hormone, stimulated the secretion of albumen in the magnum region of the oviduct (Gilbert 1971).…”