Effect of DDE on the Ca metabolism of the duck eggshell gland and its subcellular fractions; relation to the functional stage.

Administration of DDE to Indian Runner ducks (Anas platyrhynchos var.) reduced the eggshell index by 28% and the calcium content of the secreted fluid in the shell gland by 25%. DDE inhibited the functional decrease of the calcium content of the gland cells that occurred during eggshell formation. DDE reduced the functional increase in the ATP-dependent binding of Ca2+ to a microsomal subfraction FIII prepared from Ca-secreting glands forming an eggshell. In subfraction FI the Ca2+ binding was decreased by DDE even when the gland contained a mature shell. FIII probably contained calcium-secreting granules, whereas FI contained plasma membrane fragments of the gland cells.