Transport of radioiodide between blood and ovary of Japanese quail

Experimental data from blood and ovaries (oocytes) following injection of ¹²⁵Iodide were analyzed in terms of an open, two-compartmental model. Clearance of iodide by small, growing oocytes was 9.0 ul serum/mg/hour; 0.23 of the accumulated iodide left the oocytes per hour, presumably by diffusion. The accumulation of iodide by the small oocytes was shown to be saturable; K_m was 0.126 mg iodide/dl serum. These results support the concept that iodide accumulates in the small oocytes by active transport. FSH injected 2 hours prior to the ¹²⁵I caused a 50% increase in the clearance rate but no increase of the exit-rate constant.