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University of Illinois, Urbana—Champaign4
Abstract
Changes in ovarian function were measured after the administration of hormones in the mid-luteal phase of the estrous cycle in pigs and sheep. Ovarian venous blood was collected for three successive 40-min. or 60-min. periods while saline was infused at a rate approximating the rate of collection. In pigs, for the middle 40-min. period, LH was added to the saline for nine animals and FSH, prolactin and melengestrol acetate were similarly tested. Control animals (six) received only saline during the entire period. LH increased the rate of secretion of progesterone by increasing the concentration of the steroid in plasma while the rate of blood flow remained unchanged. FSH and prolactin also enhanced progesterone production in the two animals receiving each of these hormones. Whether these effects resulted from direct action on the ovary is not known. Melengestrol acetate had no effect. In sheep, during the middle third of the experimental period, LH, FSH, or prolactin was infused into treated animals. LH, tested in 12 ewes, stimulated the rate of progesterone secretion by increasing both the rate of ovarian blood flow and the concentration of steroid in the plasma. FSH produced a similar though less pronounced effect, but only two animals were tested. The one animal that received prolactin behaved like the seven controls. Wide variations between animals were seen in response to similar treatments, but the rate of flow of blood was almost always negatively correlated with the concentration of progesterone in the plasma.
1 This work was supported by grants AM06976 and HD03043 of the U. S. Department of Public Health. The 7094-1401 computer complex used to analyze the results and draw figures 1, 2 and 3 was partially supported by grant NSFGP 700 from the National Science Foundation. Technical assistance was provided by Mrs. Ruth Tyler, Mrs. Natalie Sutterlir,, Mr. R. Morris and Mr. Z. Piasek.
2 Present address: Animal Science Department, College of Agriculture, University of Wyoming, Laramie. 82070.
3 Present address: Department of Pathology, University of Michigan, Ann Arbor. 48104.
4 Department of Animal Science, Animal Genetics Division.
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