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Urinary Levels of Estrogens and Pregnanediol and Plasma Levels of Progesterone during the Menstrual Cycle of the Chimpanzee: Relationship to the Sexual Swelling

1972; Oxford University Press; Volume: 91; Issue: 1 Linguagem: Inglês

10.1210/endo-91-1-13

1945-7170

Charles E. Graham, Delwood C. Collins, HUGH ROBINSON, J.R.K. Preedy,

Neuroendocrine regulation and behavior

Urinary estrone, estradiol–17β, estriol and pregnanediol were identified and measured during 3 normal menstrual cycles in 3 chimpanzees. During the first half of the menstrual cycle, the animals excreted 1–10 βg/day estrone, 0.5–5.0 βg/day estradiol–17β, 0.1–0.8 μg/day estriol, and < 20–700 Hg/day pregnanediol. In the second half of the cycle, corresponding values were 1–20 μg/day estrone, 1–9 μg/day estradiol– 17β, < 1.0–2.5 μg/day estriol, and <20–1860 μg/ day pregnanediol. The values for estrone and estradiol–17β are similar to those found during the human menstrual cycle, but the levels for estriol are strikingly lower. Levels for urinary pregnanediol were significantly lower than in the human, both in absolute terms and in relation to the plasma progesterone levels. Plasma progesterone levels (26 subjects) were similar to those in the human. Variations during the cycle in urinary estrone, estradiol–17β, pregnanediol and plasma progesterone corresponded to those in the human. There was a marked mid—cycle peak for estrone followed by a second (luteal) peak. Urinary pregnanediol and plasma progesterone levels were low during the first half of the cycle, started rising just after mid—cycle, and peaked in the middle of the second half. The sexual swelling appeared with the rise of urinary estrogens during the first half, rapidly became maximal before mid—cycle, and started detumescing shortly after mid—cycle. The sexual swelling did not reappear with the luteal estrone peak. Treatment of amenorrheic or ovariectomized chimpanzees with estrogen regularly produced and maintained the sexual swelling. When a progestin was added, the sexual swelling promptly disappeared in spite of continued estrogen administration. The above results suggest that the sexual swelling in the menstrual cycle is caused by estrogen stimulation and that detumescence is brought about by an inhibiting effect of progesterone. (Endocrinology91: 13, 1972)