Evidence For Relaxin in Corpora Lutea of Late Pregnant Cows*

Fields, Michael J.; Fields, Phillip A.; Castro-Hernandez, Alvaro; Larkin, Lynn H.

doi:10.1210/endo-107-4-869

Cited by 58 publications

(16 citation statements)

References 21 publications

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“…Classical isolation and characterizations up to the determination of a primary sequence of the hormone have been achieved for porcine (17)(18)(19) and rat relaxins (39) and partially for the shark (40), while bovine relaxin has been well characterized (51,52).…”

Section: Sites Of Productionmentioning

confidence: 99%

Relaxin as a New Hormone*

Bryant‐Greenwood

1982

Endocrine Reviews

137

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Section: Sites Of Productionmentioning

confidence: 99%

Relaxin as a New Hormone*

Bryant‐Greenwood

1982

Endocrine Reviews

137

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“…It also is produced by the human corpus luteum during the menstrual cycle as well as by the basal plate cells of the placenta and decidual cells (10)(11)(12)(13). During late pregnancy, bovine corpora lutea produce biologically active relaxin; however, the concentrations are markedly lower than those in pigs on the basis of inhibition of uterine contractility and homologous RIA for porcine relaxin (14)(15)(16). Pelvic area increases gradually in cattle throughout gestation, then the rate increases during the last 4 days preceding normal parturition, which coincides with increasing blood concentrations of 17/3-estradiol (17jS-E 2 ) and estrone (Ei) (15)(16)(17)(18)(19)(20).…”

mentioning

confidence: 99%

“…During late pregnancy, bovine corpora lutea produce biologically active relaxin; however, the concentrations are markedly lower than those in pigs on the basis of inhibition of uterine contractility and homologous RIA for porcine relaxin (14)(15)(16). Pelvic area increases gradually in cattle throughout gestation, then the rate increases during the last 4 days preceding normal parturition, which coincides with increasing blood concentrations of 17/3-estradiol (17jS-E 2 ) and estrone (Ei) (15)(16)(17)(18)(19)(20). Administration of porcine relaxin increases both pelvic area and cervical dilatation in beef heifers during late pregnancy (21,22).…”

mentioning

confidence: 99%

Relaxin on Induction of Parturition in Beef Heifers*

et al. 1986

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Purified porcine relaxin (3000 U/mg) was administered into the cervical os of primiparous beef heifers on day 278 of gestation (approximately 5 days before parturition normally occurs) to determine its effects on the induction of parturition, changes in progesterone, estrone (E1), 17 beta-estradiol (17 beta-E2), cervical dilation, and pelvic relaxation. Heifers were assigned randomly to 1 of 3 treatments: relaxin-double (two infusions of 3000 U, 12 h apart; n = 17), relaxin-single (3000 U; n = 14), and PBS-gel vehicle (n = 16). Relaxin induced marked earlier calving (P less than 0.002) than PBS-gel vehicle. The intervals between the administration of relaxin or the PBS-gel vehicle and calving were 2.0, 2.5, and 5.3 days for heifers given relaxin-double, relaxin-single, and PBS-gel vehicle, respectively. The duration of gestation was significantly reduced (P less than 0.002) in relaxin-treated heifers compared with that in control heifers. A precipitous decrease in progesterone (7.1 ng/ml) occurred in peripheral blood plasma within 24 h after relaxin treatment. Coincident with a decline in levels of progesterone, E1 and 17 beta-E2 increased by 1700 and 400 pg/ml, respectively, an increase of 35% compared with the 12% increase in these steroids in control heifers. Mean deviations of cervical dilation increased 643%, 526%, and 11% in heifers given relaxin-double, relaxin-single, and PBS-gel vehicle, respectively. Relaxin induced maximum pelvic opening between 12-36 h after treatment. Although relaxin induced significantly earlier calving, there was no incidence (0 of 31 heifers) of retained placenta. We conclude from this study that purified relaxin administered intracervically to primiparous beef heifers during late pregnancy induced premature parturition. Marked shifts of progesterone, E1, 17 beta-E2, pelvic canal expansion, and cervical relaxation reflect the premature parturition induced by relaxin.

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“…1979: Koos andHansel. 1981], relaxin content [Fields et al. 1980| and oxytocin content [Guldenaar et al, 1984: Kruip et al, 1985.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructural Cytology of the Cyclic Corpus luteum of the Cow

O’Shea

Rodgers²,

McCoy

et al. 1990

Cells Tissues Organs

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Corpora lutea (CL) from cows on day 12 of the oestrous cycle were studied by electron microscopy to investigate whether, and how, different subpopulations of luteal cells can be identified in tissue sections. Tissues from 6 CL were examined and nucleated profiles of luteal cells were classified as large medium or small on the basis of their areas in electron micrographs. Cut-off points for area categories for large, medium and small-sized cells were based on diameters of > 25, 20–25 and < 20 µm, respectively, if the measured areas were converted to a circular shape after correction for shrinkage. The only qualitative features which distinguished cells of large size from those of small size were the presence of clusters of secretory granules, and of exocytosis of these granules, in large cells only. However, these features were observed in only 59% of large cells, probably primarily due to sampling limitations in single sections. Other qualitative features which have been regarded as diagnostic of large or small luteal cells were observed in cells in all size categories. It was concluded that large and small luteal cells in the cyclic CL of the cow are distinguishable by their ultrastructural features. However, these data do not support the recent suggestion that the mid-cycle CL of the cow contain two subpopulations of large luteal cells in approximately equal numbers.

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Evidence For Relaxin in Corpora Lutea of Late Pregnant Cows*

Cited by 58 publications

References 21 publications

Relaxin as a New Hormone*

Relaxin as a New Hormone*

Relaxin on Induction of Parturition in Beef Heifers*

Ultrastructural Cytology of the Cyclic Corpus luteum of the Cow

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