The effect of oophorectomy on plasma oestrone and androstenedione levels in the rat.

Plasma oestrone and androstenedione levels have been measured in oophorectomized and sham-operated rats by means of radioimmunoassay. The mean oestrone level in the oophorectomized animals was approximately two-thirds of that in the intact animals while the androstendione levels were about half of those in the intact rats. A direct relationship was observed between the plasma oestrone and androstenedione levels in the control animals and to a lesser extent in the oophorectomized animals. The results indicate that approximately 50% of circulating androstenedione and 30% of circulating oestrone originate in the ovaries in the female adult rat.