University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Agricultural Publications from USDA-ARS / UNL Faculty Research Service, Lincoln, Nebraska 1965 MECHANISMS CONTROLLING THE FORMATION AND PERSISTENCE OF THE CORPUS LUTEUM L. L. Anderson Iowa State University, Ames, [email protected] R. M. Melampy Iowa State University, Ames Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub Part of the Agricultural Science Commons Anderson, L. L. and Melampy, R. M., "MECHANISMS CONTROLLING THE FORMATION AND PERSISTENCE OF THE CORPUS LUTEUM" (1965). Publications from USDA-ARS / UNL Faculty. 738. https://digitalcommons.unl.edu/usdaarsfacpub/738 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. MECHANISMS CONTROLLING THE FORMATION AND PERSISTENCE OF THE CORPUS LUTEUM 1 L. L. Anderson2 and R. M. Melampy Iowa State University, Ames Mechanisms which control formation of (12); in the cow by McNutt (73, 74), Hammon~ corpora lutea during the estrous cycle, and (52), HCifliger (62) and Asdell et al. (l1); anci particularly factors affecting their persistence in the' mare by Harrison (56). The mature and regression in various reproductive stages, bovine corpus luteum may show a fluid-filled have been of considerable interest to physiolo­ cavity, whereas this gland is a solid structur'fIl gists concerned with developing methods for in the ewe, goat and sow. According to Harri~l control of the estrous cycle in domestic son (59), it has been observed in severa~ animals. Some recent reviews on control of species that theca interna cells invade th~ ovarian function are those by Chester Jones granulosa between day 1 and day 3 and tha~ and Ball (30), Anderson et al. (.2.) and Short vascularization of the gland occurs at abou~ (ill). the same time. Nearly every cell has ani endothelial covering by day 12. The reticulum found between luteal cells is produced by the Morphologic Aspects theca interna according to Solomons and Gatenby (126), but Corner (32, 33) stated that The mammalian ovary has two principal it is probably laid down by endothelial cells. functions: the production and release of ova Corner (35) investigated the distribution of and the synthesis and secretion of hormones the theca interna cells in porcine corpora which regulate the reproductive tract and lutea and found these cells scattered among secondary sexual characteristics. These hor­ the granulosa cells at day 18 of gestation. It mones also influence mating behavior and was difficult, however, to' differentiate theca affect metabolism. Following ovulation, the interna cells after this time. wall of the ruptured follicle undergoes struc­ In the sow, Corner (31, 32) observed three tural and functional changes which transform principal types of luteal cells in the corpora it into a transient endocrine gland known as lutea of pregnancy: (l) true lutein cells origi­ the corpus luteum. While the early develop­ nating from the granulosa; (2) cells witli ment of the corpus lateum appears to be quite smaller round or oval and more chromatic similar in many mammalian species, the nuclei which appear on the periphery of the functional life span varies according to whether gland and along the connective tissue septa the animal is nonpregnant, pseudopregnant, and (3) cells with a spindle shape and a cyto­ pregnant or lactating. In eutherian mammals, plasm which stained dark brown or purple wiU it is generally accepted that the granulosa Mallory's stain. It was also noted that therE cells are transformed into luteal cells of the were transitional stages among the threE corpus lateum. The fate of theca interna cells types. is less clear and there appear to be species In evaluating the physiologic aspects of thE differences as to their subsequent functional formation and persistence of the corpus luteum significance in the corpus luteum. The litera­ it is desirable to consider briefly the mor· ture pertaining to the histogenesis of the phologic development and retrogression 0: corpus luteum has been reviewed by Marshall this gland. In the ewe, according to Warbrittol (79); Corner (31, 32); Hett (60); Pratt (103); (ill), the corpus luteum develops from botl Harrison (58, 59) and Brambell (23). According the granulosa and theca interna, but the lutea' to Amoroso and Finn (~) the original descrip­ cells of the mature gland appear to originat4 tion of the corpus luteum is usually credited entirely from the former. Three types 0 to Volcherus Coiter in 1573, but Harrison cells (embryonic, normal and regressing (58) has stated that Vesalius had observed it were noted and these represented three phasel in the human ovary about 30 years earlier. in the life cycle of a single luteal cell derive. The developmental morphology of the corpus from the granulosa. The ovine corpus luteun luteum in the ewe has been described by reaches its maximum size at about the middl' Marshall (78), Grant (50), Quinlan and Mare of the cycle (Casida and McKenzie, 28). Th, (105), Casida and McKenzie (28) and War­ colo.r of the gland changes from blood red il britton (128); in the goat by Harrison (57); in an early corpus luteum through translucen the sow by Corner (31, 32, 34, 35)and Barker pink, opaque pink, cream and finally yellow. 1 Journal Paper No. J -4910 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa. Project Nc 1325. Supported by US PHS, National Institutes of Health (Grant HD 01168-05) and American Cyanamid Co., Princeton,N.: 2Lalor Foundation Fellow, 1964, at the Station de Recherches de Physiologie Anima1e, Centre National de Recherche Zoo techniques, J ouy-en-J osas, France. 64 Corner (34) noted in the sow that, during the have been reported by Weeth and Herman ek following ovulation, corpora lutea attain (ill) and Foley and Reece (48). The latter we diameter of 8 to 10 mm. Ii the animal is investigated the gross and microscopic a regnant, there is further growth until an anatomy of the bovine corpus luteum between p verage diameter of 10 to 11 mm. is reached. 25 and 45 days of gestation and stressed the ~istologicallY it has not been possible to variation in size, shape and staining qualities distinguish between glands of the cycle and of the individual luteal cells. It was demon­ those of early pregnance. At approximately strated that the luteal tissue was more com­ day 16 of the cycle, a change occurs in the pact and that the cells were larger and more appearance of the corpus luteum in non­ rounding in shape, with the cytoplasm being pregnant animals. By day 18 the diameter more lightly stained between days 25 and 30. decreases to 6 mm., and the color changes Moss et al. (95, 96) have reported studies from pink of active capillary circulation to dealing with the histochemistry of the bovine whitish of scar tis sue, indicating retrogres­ reproducti ve tract, including the corpus sive changes in the nature offibrous involution. luteum. These investigators noted that the Eventually all that remains of the site of an cyclic corpus luteum contained large amounts ovarian follicle, and subsequently a corpus of alkaline phosphatase until about the thir­ luteum (either of a cycle or pregnancy), is a teenth day of the cycle. This enzyme was very small mass of scar tissue, a corpus albicans. low or, except for capillary endothelium, McNutt (73, 74) studied the cyclic bovine absent in later stages of the cycle. Both corpus luteum as well as the corpus luteum theca and granulosa luteal cells contain phos­ of pregnancy and concluded that the luteal phatase activity up to mid-cycle; it is first cells arise from both the granulosa and theca lost from the granulosa cells and later from interna, but he added that many luteal cells the theca cells. The corpus luteum of cycling exhibited intermediate characteristics and that cows differs markedly from the corpus luteum the origin of these cells could not be stated of pregnancy with regard to the presence of with certainty. The newly formed corpus phosphatase. The presence of phosphatase in luteum may be identified on the fifth day when the former and not in the latter would suggest it protrudes above the level of the ovary. The that phosphatase is not concerned in the young corpus luteum measures about 6 to secretory activity of the corpus luteum but, 8 mm. in diameter. By 8 days it has increased rather, may be concerned in the initial stages to 18 to 20 mm., and when it is mature it of growth and development of this organ. measures 20 to 25 mm. The cyclic corpus The luteal cells of bovine corpora lutea luteum begins to regress about day 16 follow­ between 16 and 33 days of gestation have ing estrus. There is, however, no marked been classified into five types on the basis of reduction in size until the organ is 18 to 20 their cytological characteristics by Foley days old. and Greenstein (47). Type I cells represent Melampy and Gay (83) made a study of the "immature" luteal cells and Type II are weight of both the ovary and its corpus luteum mature cells which have reached their max­ of pregnancy in the cow. The estimated age imum size and development. Type III cells of the corpus luteum was based on the crown­ are believed to be in the initial stage of rump length of the fetus. In the 298 cows regression which continues through Type IV examined, 90 percent of the ovaries, including and terminates with Type V cells.