A note on amounts of [14C] in laying hens' blood after intramuscular administration of [4-14C]-estrone.

[4-14C]-Estrone in 2 ml. ethylene glycol was injected into the breast muscles of S.C. White Leghorn laying hens and the amounts of plasma [14C] per ml. whole blood were measured at various times thereafter. Maximal values were observed at 30 to 50 minutes after injection. The values then declined logarithmically with time and with a half-life of about 80 minutes between 40 and 270 minutes after injection.