Biology of Reproduction, Vol 42, 139-149, Copyright © 1990 by Society for the Study of Reproduction

ARTICLES

Physiological and immunocytochemical evidence for a new concept of blood flow regulation in the corpus luteum

MC Wiltbank, KP Gallagher, AK Christensen, RK Brabec and PL Keyes
Department of Physiology, University of Michigan, Ann Arbor 48109.

To explain the high rate of blood flow in the corpus luteum, we hypothesize that luteal blood vessels offer minimal resistance to flow and are incapable of vasomotion. This hypothesis was tested in rabbits at mid-pseudopregnancy by measuring blood flow in the corpus luteum and ovarian stroma with tracer-labeled microspheres at three levels of arterial blood pressure, which was manipulated by constricting the aorta above the ovarian artery. In addition, the distribution of vascular smooth muscle in the ovary was evaluated with morphological and immunocytochemical techniques. Decreases in arterial pressure were paralleled by reductions in blood flow in the corpus luteum, whereas ovarian stromal blood flow was unchanged. Consistent with our hypothesis, there was no change in the low level of vascular resistance offered by blood vessels in the corpus luteum, supporting the view that they are maximally dilated and incapable of autoregulation. Morphologically, the vessels within the corpus luteum appeared as large sinusoidal capillaries without smooth muscle, providing an anatomical explanation for the lack of vasomotor control demonstrated physiologically. The absence of vascular smooth muscle was confirmed with immunocytochemistry using an antibody against the muscle-specific intermediate filament, desmin. The fluorescein-labeled antibody decorated arteries and arterioles within the ovarian stroma and near the capsule of the corpus luteum, but did not decorate vessels in the corpus luteum of pseudopregnancy, providing additional evidence that the vessels of the corpus luteum lack the smooth muscle investment necessary to change vascular caliber. From these findings, we have proposed a novel scheme to explain intraovarian blood flow regulation. Vascular resistance in the ovarian stroma, as in most tissues, is acutely regulated by dilation or constriction of intratissue arterioles. In contrast, vascular resistance within the corpus luteum is modeled as a relatively invariable parameter, fixed at a low level by the morphological characteristics of the luteal vasculature. Therefore, the corpus luteum operates on a linear (maximally "vasodilated") pressure-flow curve, does not actively regulate intratissue blood flow, and is subject to acute regulation of perfusion only through changes in extra-luteal vessels.

This article has been cited by other articles:

				L. E. Henkes, B. T. Sullivan, M. P. Lynch, R. Kolesnick, D. Arsenault, M. Puder, J. S. Davis, and B. R. Rueda Acid sphingomyelinase involvement in tumor necrosis factor {alpha}-regulated vascular and steroid disruption during luteolysis in vivo PNAS, June 3, 2008; 105(22): 7670 - 7675. [Abstract] [Full Text] [PDF]

				K. Shirasuna, S. Watanabe, T. Asahi, M. P B Wijayagunawardane, K. Sasahara, C. Jiang, M. Matsui, M. Sasaki, T. Shimizu, J. S Davis, et al. Prostaglandin F2{alpha} increases endothelial nitric oxide synthase in the periphery of the bovine corpus luteum: the possible regulation of blood flow at an early stage of luteolysis Reproduction, April 1, 2008; 135(4): 527 - 539. [Abstract] [Full Text] [PDF]

				A. T Grazul-Bilska, C. Navanukraw, M. L. Johnson, D. A Arnold, L. P Reynolds, and D. A Redmer Expression of endothelial nitric oxide synthase in the ovine ovary throughout the estrous cycle. Reproduction, October 1, 2006; 132(4): 579 - 587. [Abstract] [Full Text] [PDF]

				E. H. Y. Ng, C. C. W. Chan, W. S. B. Yeung, and P. C. Ho Comparison of ovarian stromal blood flow between fertile women with normal ovaries and infertile women with polycystic ovary syndrome Hum. Reprod., July 1, 2005; 20(7): 1881 - 1886. [Abstract] [Full Text] [PDF]

				K Lakhani, A M Seifalian, W U Atiomo, and P Hardiman Polycystic ovaries Br. J. Radiol., January 1, 2002; 75(889): 9 - 16. [Abstract] [Full Text] [PDF]

				B. E. Friden, E. Runesson, M. Hahlin, and M. Brannstrom Evidence for nitric oxide acting as a luteolytic factor in the human corpus luteum Mol. Hum. Reprod., May 1, 2000; 6(5): 397 - 403. [Abstract] [Full Text] [PDF]

				D. L. Livant, R. K. Brabec, K. J. Pienta, D. L. Allen, K. Kurachi, S. Markwart, and A. Upadhyaya Anti-invasive, Antitumorigenic, and Antimetastatic Activities of the PHSCN Sequence in Prostate Carcinoma Cancer Res., January 1, 2000; 60(2): 309 - 320. [Abstract] [Full Text]

				F. S. Khan-Dawood, J. Yang, and M. Y. Dawood Immunohistological Localization and Expression of a-Actin in the Baboon (Papio anubis) Corpus Luteum J. Histochem. Cytochem., January 1, 1997; 45(1): 71 - 78. [Abstract] [Full Text] [PDF]