title: Evidence for functional arterio--venous anastomoses in the ovaries of sheep.
abstract: Vessels with histological features characteristic of arterio--venous anastomoses were found in the stroma but not in CL. In 5 conscious ewes at the mid-luteal stage of the oestrous cycle, ovarian blood flow was significantly greater (P less than 0.025) with microspheres of 50 than of 15 micrometers diameter in ovaries without CL (0.23 +/- 0.04 (s.e.m.) and 0.11 +/- 0.02 ml/min, respectively), but not in ovaries with CL (4.42 +/- 0.86 and 3.73 +/- 0.70 ml/min, respectively). In 5 similar but anaesthetized ewes, the portion of each ovarian artery within the ovarian vascular pedicle was bypassed with re-entrant catheters through which microspheres were perfused. A greater proportion (P less than 0.01) of 50 than of 15 micrometers microspheres was retained in ovaries with (90 and 79%) or without (82 and 45%) a CL. It is concluded that functional arterio--venous anastomoses are present in sheep ovaries.
mesh_terms: D000818:Animals; D001163:Arteriovenous Anastomosis / Q000502:physiology*; D001783:Blood Flow Velocity; D005260:Female; D008863:Microspheres; D010053:Ovary / Q000098:blood supply*; D010477:Perfusion; D012039:Regional Blood Flow; D012756:Sheep / Q000502:physiology*