Distribution of 153Gd in F1 Quail

Eggs laid by 153 Gd-labeled Japanese quail were collected each day for 24 days. Maximum transference of the lanthanide to an oocyte approximated 27% of the dose given the quail and occurred usually for the egg collected on the third day. The 24 largest oocytes from each of 2 quail were removed 18 hr after labeling the quail. The curve for a plot of percent 153Gd vs. gram of oocyte for these 24 oocytes approximated a log-log function. Eggs double-labeled with 153 Gd and Sudan black B showed no label in the latebra. Quail hatched from labeled eggs were dissected at various times up to 67 days of age. The percent of egg 153 Gd that was found in the F1 quail decreased from 100% to approximately 55% during the first 14 days. The percentage recovery for mature quail was 55.8%. The major portion of the 153Gd present in each F1 quail was found in the yolk sac and ranged from 96.0% for hatchlings a few hours old to 73.3% for mature quail. The weight of the yolk sac decreased from .7 g for hatchlings to .04 g for mature quail. The first 5 eggs laid by producing F1 quail contained a total of .643% of the 153 Gd in these quail. The graph curve for these eggs for percent 153Gd vs. day of collection approximated an exponential function, in contrast to the marked maximum seen for 153Gd levels in eggs laid by the parent quail.