title: Parathyroid hormone and eggshell calcification in Japanese quail.
abstract: The effect of parathyroid hormone (PTH) on egg-shell calcification has been investigated in egg-laying Japanese quail. Lilly parathyroid extract (PTE) when injected into quail within 2-6 h of oviposition caused a significantly increased deposition of a chronic 45Ca label into the sequential egg-shell compared with the previous egg in the clutch, indicating increased mobilization of bone Ca and its subsequent incorporation into the egg-shell. At the same time egg-shell weight/unit area and egg-shell Ca/unit area were significantly decreased. Parathyroid extract injected 12-16 after oviposition had none of these effects. Purified PTH also caused a significant decrease in egg-shell weight/unit area if injected within 2-6 h of oviposition. This result indicated an action of PTH either directly or indirectly on the avian oviduct limiting egg-shell calcification. The loss of responses in the 12-16 h treated birds may reflect high endogenous PTH levels with subsequent saturation of target organ receptors.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003370:Coturnix; D004528:Egg Shell / Q000032:analysis; D005260:Female; D010060:Ovulation; D010281:Parathyroid Hormone / Q000494:pharmacology*
chemical_list: D010281:Parathyroid Hormone; D002118:Calcium