We have investigated the role of the utero-ovarian ligament (UOL) in the alternating ovulatory performance of the ovaries in the capuchin monkey. In intact animals, the ovulation rate was near 90%, with 67.5% of ovulations occurring in the left ovary. Sectioning the UOL in any phase of the cycle decreased the ovulation rate by 40%, and restricted ovulations to the ovary still connected to the uterus by the UOL. Estradiol and progesterone levels were significantly reduced throughout the following cycles in treated monkeys. Removal of the ovary that had been disconnected 18-20 months previous, restored both the ovulation rate and normal steroid levels. Histological study of the UOL revealed the presence of arteries, veins, lymph vessels, and nerves. Electrical stimulation of the UOL was followed by an abrupt discharge of estradiol by the ovary bearing the follicle, advancing ovulation which was followed by a normal luteal development. Conversely, stimulation of the ovary bearing a corpus luteum did not modify either the ovarian or the peripheral levels of ovarian steroids. The UOL ligament appeared to be functional for products arising from the uterus. The distribution and effects of hCG injected intrauterinely depended upon the day of the luteal phase. In the early luteal phase, hCG was distributed symmetrically between both ovaries, and increased the progesterone secretion by the ovulatory ovary only. In the late luteal phase, hCG was preferentially distributed to the ovulatory ovary, and increased the progesterone secretion by both ovaries. The present findings provide evidence for a local mechanism, throughout the UOL, controlling both the alternation of ovulation and the transfer of substances originating in the uterus that regulate the ovarian function in primates.
In basal conditions, progesterone concentrations were similar in the ovarian veins of the ovary +CL (3211 +/- 526 ng/ml) and the ovary -CL (3165 +/- 554 ng/ml), but after blocking the blood flow between the ovary +CL and the uterus, the progesterone values in the vein draining the ovary -CL decreased to 1218 +/- 394 ng/ml (P less than 0.01). When [3H]progesterone was injected in the ovary +CL, the radioactivity appeared earlier and more concentrated in the vein draining the ovary -CL (30 sec, 0.53% of injected dose) than in the femoral vein (150 sec, 0.08% of injected dose). Removal of the ovary +CL was followed by a brief maintenance of peripheral progesterone within luteal-phase levels. The in-vitro progesterone production by a suspension of cells isolated from the corpus luteum was 47.5 +/- 12.8 ng/ml/2 h, whereas luteal-like cells isolated from the ovary -CL secreted 14.3 +/- 6.0 ng/ml/2 h (P less than 0.01) into the medium. We therefore suggest that the symmetrical and high secretion rate of progesterone by the ovaries of the capuchin monkey indicates a between-ovary communication system, and that the luteal-like tissue of the ovary -CL can produce relatively large amounts of progesterone.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.