IMPLANTATION IN ARMADILLOS OVARIECTOMIZED DURING THE PERIOD OF DELAYED IMPLANTATION

1956 ◽  
Vol 14 (2) ◽  
pp. 121-NP ◽  
Author(s):  
G. D. BUCHANAN ◽  
A. C. ENDERS ◽  
R. V. TALMAGE
Keyword(s):  
Corpus Luteum ◽  
Delay Period ◽  
Early Gestation ◽  
Bilateral Ovariectomy ◽  
Delayed Implantation

SUMMARY The effect of ovariectomy during delayed implantation on the fate of the free blastocyst has been studied in the armadillo. If bilateral ovariectomy is performed about the middle of the 4-month delay period, implantation occurs 30–34 days later and is indistinguishable from normal implantation. In animals ovariectomized toward the end of the delay period, implantation occurs at the time when normal implantation would have been expected, which is less than 30 days postoperatively. However, resorption or abortion follows shortly thereafter. Removal of the corpus luteum towards the end of the delay period for the most part results in loss of the blastocyst and non-implantation. Removing the corpus luteum in early gestation causes loss of the embryos, but no effect was observed following loss of the corpus luteum in animals past approximately the first third of gestation. A possible explanation of the findings is discussed.

I.—On the Pregnancy Rate in the Lactating Mouse and the Effect of Suckling on the Duration of Pregnancy

1932 ◽  
Vol 51 ◽  
pp. 1-7 ◽  
Author(s):  
L. Mirskaia ◽  
F. A. E. Crew
Keyword(s):  
Mammary Gland ◽  
Corpus Luteum ◽  
Pregnancy Rate ◽  
Inhibitory Action ◽  
Reproductive Activity ◽  
Delayed Implantation ◽  
Prolonged Pregnancy ◽  
Suggested Explanation ◽  
Duration Of Pregnancy

Summary1. The pregnancy rate of primiparæ, suckling their young, was, in this experiment, 24·1 per cent.; that of multiparæ suckling their young, 50 per cent. It is shown that this difference is not due to differences in the incidence of ovulation associated with postpartum œstrus. The suggested explanation of this difference between puberal and adult groups is that a certain level of somatic maturity is a prerequisite for full reproductive activity.2. In all cases the duration of pregnancy was prolonged. The degree of prolongation was variable and could not be related to the number of young in the uterus or suckling. The results provide no support for the suggestion that this prolongation, due to delayed implantation of the fertilised ova, is to be referred to an inhibitory action on the part of the mammary gland. The suggestion is made that the delayed implantation and prolonged pregnancy are due to inability on the part of the corpus luteum to cater adequately for implantation and lactation synchronously.

scholarly journals Immunolocalization of steroidogenic enzymes in the corpus luteum and placenta of the Japanese black bear, Ursus thibetanus japonicus, during pregnancy

Reproduction ◽  
2001 ◽  
pp. 587-594 ◽  
Author(s):  
T Tsubota ◽  
S Taki ◽  
K Nakayama ◽  
JI Mason ◽  
S Kominami ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Corpus Luteum ◽  
Fetal Development ◽  
Black Bear ◽  
Corpora Lutea ◽  
Luteal Cells ◽  
Ursus Thibetanus ◽  
Delayed Implantation ◽  
Post Implantation ◽  
Implantation Period

The Japanese black bear, Ursus thibetanus japonicus, is a seasonal breeder and shows delayed implantation for several months during pregnancy. The objective of this study was to clarify the steroidogenic capability of the corpus luteum and placenta during pregnancy, including both delayed implantation and fetal development, by immunolocalization of steroidogenic enzymes in these organs of the Japanese black bear. Ovaries and placentae from 15 wild Japanese black bears, which had been killed legally by hunters and were thought to be pregnant, were used in an immunocytochemical study to localize the cholesterol side chain cleavage cytochrome P450 (P450scc), 3beta-hydroxysteroid dehydrogenase (3betaHSD), 17alpha-hydroxylase cytochrome P450 (P450c17) and aromatase cytochrome P450 (P450arom) by the avidin-biotin-peroxidase complex method using polyclonal antisera raised in mammals against P450scc, 3betaHSD, P450c17 and P450arom. P450scc and 3betaHSD were localized in all luteal cells throughout pregnancy. P450c17 was present in a few luteal cells, especially in the outer area of the corpus luteum throughout pregnancy, but the number of positively immunostained cells decreased during the post-implantation period. Cells positively immunostained for P450c17 were significantly smaller than negatively immunostained cells (P < 0.01). P450arom was present sporadically in a few luteal cells throughout pregnancy, but the number of positively immunostained cells decreased during the post-implantation period. The size of cells positively immunostained for P450arom was not significantly different from that of negatively immunostained cells. The whole placenta was negatively immunostained for P450scc, 3betaHSD and P450c17, but P450arom was present in the syncytiotrophoblasts and endothelial cells of maternal blood vessels. These results indicate that, in the Japanese black bear, corpora lutea are a source of progesterone which may play an important role in the maintenance of delayed implantation and fetal development during pregnancy. Corpora lutea have a minimum capability to synthesize androgen in small luteal cells and oestrogen in normal-sized luteal cells during pregnancy, and placentae have the ability to synthesize oestrogen during late pregnancy.

Morphological and vascular changes in the corpus luteum during early gestation of bovine SCNT-derived pregnancies

Placenta ◽  
2014 ◽  
Vol 35 (9) ◽  
pp. A23
Author(s):  
Fábio Pinaffi ◽  
Izabelle Jardim ◽  
Juliano Sangalli ◽  
Rafael Sampaio ◽  
Flavio Meirelles ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Vascular Changes ◽  
Early Gestation

THE PRESENCE OF A FUNCTIONAL CORPUS LUTEUM DURING DELAYED IMPLANTATION IN THE ARMADILLO

1954 ◽  
Vol 11 (1) ◽  
pp. 44-49 ◽  
Author(s):  
R. V. TALMAGE ◽  
G. D. BUCHANAN ◽  
F. W. KRAINTZ ◽  
E. A. LAZO-WASEM ◽  
M. X. ZARROW
Keyword(s):  
Corpus Luteum ◽  
Respiratory Quotient ◽  
Reproductive Physiology ◽  
Delayed Implantation ◽  
Luteal Tissue

SUMMARY The reproductive physiology of the armadillo has been studied with special emphasis on the hormonal problems related to the phenomenon of delayed implantation which occurs in this species. Ovulation occurs spontaneously in the unmated animal, and a corpus luteum is formed which is grossly indistinguishable from, and histologically similar to, the corpus luteum of pregnancy. Both this and the corpus luteum normally present during the period of delayed implantation are functional, as indicated by the increased respiratory quotient of the luteal tissue and the high progestin activity of the serum. It is tentatively suggested that the failure of the blastocyst to implant is due to lack of a proper ratio of oestrogen and progestin and not to an insufficiency of progestin alone.

scholarly journals Concentrations of Progesterone Alter the Odds of Retention of Transferred Bovine Embryos

2017 ◽  
Vol 2 (1) ◽  
pp. 1-6
Author(s):  
Cuadra EJ
Keyword(s):  
Corpus Luteum ◽  
Uterine Horn ◽  
Control Group ◽  
Bovine Embryos ◽  
Blood Samples ◽  
Early Gestation ◽  
Decisive Effect ◽  
Progesterone Secretion ◽  
Body Weights

Two studies were conducted to examine the role of progesterone on the odds of survival of embryos transferred into lactating and non - lactating recipient cows. In each study, recipients were synchronized for estrus following the Select Synch + CIDR ® protocol. O n d 7, after exhibiting estrus, embryos were inserted in all cows bearing a viable corpus luteum; embryos were placed in the uterine horn of the ovulating side. Randomly, animals were divided into two groups. Contrary with the control group, cows in the CI DR - group had a CIDR inserted on that same day the embryo was inserted and removed 14 days later. Blood samples for analysis of progesterone were taken at insertion (d 7) and continued at 7 - day intervals for three more weeks. All animals were weighed and bo dy condition scored at the beginning of the studies. Pregnancy diagnosis was performed around d 90. No significant differences were observed in body weights between treatments. Progesterone between treatments within days and between days within treatments are reported. Progesterone between pregnant and non - pregnant cattle was also reported between treatments and within treatments. Progesterone seems to increase the odds of retention of transferred bovine embryos during early gestation. Results also seem to point out that patterns of progesterone secretion during the first two weeks after the transfer have a decisive effect on the survival of bovine embryos. Nevertheless, authors of this document suggest that more research is needed to closely examine these f indings.

SOME EFFECTS OF OVARIECTOMY AND INJECTION OF OVARIAN HORMONES IN THE ARMADILLO

1959 ◽  
Vol 19 (3) ◽  
pp. 251-NP ◽  
Author(s):  
A. C. ENDERS ◽  
G. D. BUCHANAN
Keyword(s):  
Corpus Luteum ◽  
Ovarian Hormones ◽  
Uterine Weight ◽  
Bilateral Ovariectomy

SUMMARY The uteri of armadillos, spayed before they had ovulated, declined in weight. Administration of oestradiol to such animals results in a gain in uterine weight due primarily to an increase in thickness of the myometrium. In animals bilaterally ovariectomized subsequent to ovulation, implantation occurred regularly 22–24 days postoperatively, with little loss of blastocysts. The administration of progesterone to animals from which the ovary containing the corpus luteum has been removed is compatible with maintenance of the blastocyst. In one instance an unimplanted blastocyst was recovered on day 31 after operation. The enigma of implantation following bilateral ovariectomy in this species remains unexplained.

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