The effects of ovariectomy and progesterone on peripheral aromatization in the female rhesus monkey

We investigated the acute effects of surgery, i.e. ovariectomy, the long-term effects of ovariectomy, and the effects of progesterone on the peripheral aromatization of androstenedione in rhesus monkeys (Macaca mulatta). For the acute effects of surgery, 7 rhesus monkeys were given a pulse of ³H]androstenedione/¹⁴C]estrone 2 weeks before and immedately after ovariectomy. In each case all urine was collected for 4 days and analyzed for radioactivity as estrone glucuronide and the peripheral aromatization calculated from the isotope ratios. Similarly, 5 monkeys were studied before and 18 months after ovariectomy. The acute effects of surgery resulted in a significant decrease in the peripheral aromatization of androstenedione to estrone from a mean±SE of 0.94 ± 0.26 to 0.61 ± 0.19%, P = 0.0452. Conversely, the long-term effects of ovariectomy resulted in a significant increase in peripheral aromatization from 0.38 ± 0.06 to 0.67 ± 0.12%, P = 0.0207. In 7 monkeys the peripheral aromatization was measured before and 10 days after the administration of progesterone, 100 mg in oil. There was no difference in peripheral aromatization before, 0.62 ± 0.04% and after progesterone, 0.58 ± 0.05%, P = 0.10. We conclude that the acute stress of ovariectomy, or possibly the loss of ovarian aromatizing tissue, results in a decline in peripheral aromatization, but ovariectomy will have the long-term effect of an increase in aromatization, and that the presence or absence of progesterone does not play a role.