Secretion Rates of Estradiol, Testosterone, and Progesterone from Right and Left Rabbit Ovaries Cannulated Concurrently or Successively

Based upon very large differences in the steroid content of blood obtained by concurrent cannulations of both ovarian veins, Shaikh and Harper (1972) have implied that one member of a pair may act predominantly as the steroid-secreting ovary. To test this hypothesis, estradiol, testosterone, and progesterone were measured by radioimmunoassay in the ovarian venous plasma of six rabbits in which right and left ovarian veins were cannulated concurrently and in eight others in which right and left ovarian veins were cannulated successively. The duration of blood collections ranged from 5 to 20 min/ovary and the resultant calculated amounts of whole blood obtained/ovary/h ranged between 54 and 252 ml. In most cases, paired ovaries secreted comparable amounts of steroid. Relative to steroid concentration, the highest ratios obtained between right and left ovarian veins were 1.0-3.0 for estradiol, 1.0-1.6 for testosterone, and 1.0-1.8 for progesterone. The highest ratios of secretion rate/ovary/h ranged from 1.0 to 3.0 for estradiol, 1.0 to 1.4 for testosterone, and 1.0 to 1.5 for progesterone. These results are in sharp contrast to those reported by Shaikh and Harper and fail to support their hypothesis of marked differential secretion rates by the two ovaries.