LYSOSOMAL FUNCTION IN THE CORPUS LUTEUM OF THE SHEEP

1968 ◽  
Vol 40 (3) ◽  
pp. 325-NP ◽  
Author(s):  
J. T. DINGLE ◽  
MARY F. HAY ◽  
R. M. MOOR
Keyword(s):  
Corpus Luteum ◽  
Functional Significance ◽  
Subcellular Fraction ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Lysosomal Function ◽  
Luteal Regression ◽  
Pregnant Sheep ◽  
A Cell

SUMMARY A subcellular fraction containing particles showing the characteristics of lysosomes has been isolated from the corpus luteum of the sheep. Histochemical and biochemical observations have demonstrated that the lysosomes increase in size and fragility late in the oestrous cycle. Similar changes were not found in the corpora lutea of pregnant animals. The observed increase in lysosomal fragility is one of the earliest changes associated with luteal regression, and is thought to be of functional significance in the involution of the lutein cells. The possible modification of lysosomal function by the production of a cell-specific lytic factor from the uterus of non-pregnant sheep is discussed.

THE EFFECT OF HYPOPHYSIAL STALK-SECTION ON THE CORPUS LUTEUM OF THE GUINEA-PIG

1971 ◽  
Vol 50 (4) ◽  
pp. 625-635 ◽  
Author(s):  
DOREEN V. ILLINGWORTH ◽  
J. S. PERRY
Keyword(s):  
Growth Rate ◽  
Guinea Pig ◽  
Corpus Luteum ◽  
Guinea Pigs ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Normal Cycle ◽  
Luteal Regression ◽  
Normal Regression ◽  
And Function

SUMMARY The effects of hypophysial stalk-section on the growth and function of the corpus luteum of the non-pregnant guinea-pig have been compared with the effects of hypophysectomy (as previously described) and with the effects of prolactin administered to hypophysectomized animals. Stalk-section soon after ovulation did not impair the growth of the corpora lutea nor their ability to secrete progesterone. Stalk-section before day 9 of the oestrous cycle prevented the normal regression of the corpora lutea; they continued to grow and 3 weeks after ovulation were as large as those of pregnant animals, or of non-pregnant hysterectomized guinea-pigs. The corpora lutea regressed irregularly during the following 2 weeks. When performed on, or later than day 9, stalk-section did not prevent luteal regression at the normal time. Administration of prolactin (10 i.u./day) to hypophysectomized guinea-pigs restored the growth-rate of the corpora lutea, which reached sizes comparable to those of the normal cycle, and those of stalk-sectioned animals, by 10 days after ovulation. Our results indicate that prolactin can have substantial luteotrophic activity in the guinea-pig.

THE EFFECT OF EXOGENOUS GONADOTROPHINS ON THE CONCEPTUS AND CORPUS LUTEUM IN PREGNANT SHEEP

1969 ◽  
Vol 44 (4) ◽  
pp. 495-499 ◽  
Author(s):  
R. M. MOOR ◽  
L. E. A. ROWSON ◽  
MARY F. HAY ◽  
B. V. CALDWELL
Keyword(s):  
Corpus Luteum ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Secondary Response ◽  
Corpora Lutea ◽  
Luteal Regression ◽  
Pregnant Sheep ◽  
Primary Action

SUMMARY Interruption of pregnancy occurred in 25 out of 57 unilaterally pregnant sheep after gonadotrophins (pregnant mare serum and human chorionic gonadotrophin) had been injected at various times, ranging from day 17 to 70, in order to induce additional corpora lutea. The conceptus became moribund before luteal regression occurred. The same gonadotrophins administered on day 50 to hysterectomized sheep did not affect the corpora lutea. It would therefore appear that the primary action of the gonadotrophins is on the conceptus and that luteal regression is a secondary response.

A comparative study of the corpus luteum

1995 ◽  
Vol 7 (3) ◽  
pp. 303 ◽  
Author(s):  
RT Gemmell
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Hormonal Control ◽  
Egg Laying ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Embryonic Diapause ◽  
Alternative Reproductive Strategy ◽  
Uterine Development

The corpus luteum (CL) is a transitory organ which has a regulatory role in reproduction. Sharks, amphibians and reptiles have corpora lutea that produce progesterone which influences the rate of embryonic development. The egg-laying monotremes and the two major mammalian groups, eutherian and marsupial, have a CL that secretes progesterone. Most eutherians have allowed for the uterine development of their young by extending the length of the oestrous cycle and the CL or placenta actively secretes progesterone until birth. Gestation in the marsupial does not extend beyond the length of an oestrous cycle and the major part of fetal development takes place in the pouch. Where the extension of the post-luteal phase in the eutherian has allowed for the uterine development of young, the marsupial has extended the pre-luteal phase of the oestrous cycle and has evolved an alternative reproductive strategy, embryonic diapause. The mechanism for the secretion of hormones from the CL has been controversial for many years. Densely-staining secretory granules have been observed in the CL of sharks, marsupials and eutherians. These granules have been reported to contain relaxin, oxytocin or mesotocin, and progesterone. A hypothesis to suit all available data is that all hormones secreted by the CL are transported within such granules. In conclusion, although there are obvious differences in the mode of reproduction in the two main mammalian groups, it is apparent that there is a great deal of similarity in the hormonal control of regression of the CL and parturition.

CHANGES IN THE DENSITY AND PROGESTERONE CONTENT OF LUTEAL TISSUE IN THE EGYPTIAN BUFFALO DURING THE OESTROUS CYCLE

1967 ◽  
Vol 39 (2) ◽  
pp. 163-171 ◽  
Author(s):  
A. S. EL-SHEIKH ◽  
FRANÇOIS B. SAKLA ◽  
SAFAA O. AMIN
Keyword(s):  
Corpus Luteum ◽  
Cell Volume ◽  
Distribution System ◽  
Oestrous Cycle ◽  
Luteal Cell ◽  
Corpora Lutea ◽  
Luteal Cells ◽  
Functional Changes ◽  
Parallel Increase ◽  
Luteal Tissue

SUMMARY The histological and functional changes of 31 corpora lutea of Egyptian buffaloes during the various phases of the oestrous cycle were studied. The volumes of the corpora lutea were calculated, the volume per cell, the cell volume and the volume of the intercellular spaces were estimated from transverse serial sections stained with haematoxylin and eosin, Mallory's triple stain or van Gieson's stain. The nuclear volumes were also determined and the cytoplasmic volume was calculated. The progesterone content was estimated using column absorption chromatography and a counter-current distribution system. It was concluded that the luteal cells increase both in volume and in number due to mitosis. The luteal cells decrease in volume after the 15th day after ovulation, the cells lose their distinct outlines in the regressive stage and disappear completely in the corpus albicans. There was a parallel increase in luteal cell volume and progesterone content until the 15th post-ovulatory day followed by a decrease in the regressive phase and disappearance of the hormone in the corpus albicans. A highly significant correlation (r = +0·875) was found between the progesterone content and the cytoplasmic volume. Progesterone concentration/g. luteal tissue increased from the corpus haemorrhagicum to the mature corpus luteum, decreased in the regressive corpus luteum and completely disappeared in the corpus albicans.

STEROID AND PROSTAGLANDIN SECRETION BY THE CORPUS LUTEUM, ENDOMETRIUM AND EMBRYOS OF CYCLIC AND PREGNANT PIGS

1979 ◽  
Vol 82 (3) ◽  
pp. 425-428 ◽  
Author(s):  
J. WATSON ◽  
C. E. PATEK
Keyword(s):  
Corpus Luteum ◽  
Late Stage ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Reproductive Tissues ◽  
Prostaglandin F

Prostaglandin F2α (PGF2α) secreted by the reproductive tissues of the pig in vitro was measured and it was found that the levels secreted by the corpus luteum and endometrium of early pregnant sows were significantly lower than those secreted by tissues during the late stage of the oestrous cycle. They were, however, comparable to levels secreted by tissues from the mid-stage of the oestrous cycle. Embryos also secreted significant amounts of PGF2α. Secretion of progesterone and oestradiol by the corpora lutea of both cyclic and pregnant pigs fell within accepted limits but embryos were also found to secrete significant amounts of oestradiol. The results suggest that luteal maintenance in the early pregnant pig is unlikely to be directly due to reduced synthesis of PGF2α.

EFFECT OF INTRA-UTERINE FOREIGN BODIES AND OF PROSTAGLANDIN ADMINISTRATION ON PROGESTERONE SECRETION DURING THE OESTROUS CYCLE OF THE GUINEA-PIG

1976 ◽  
Vol 70 (1) ◽  
pp. 39-45 ◽  
Author(s):  
F. R. BLATCHLEY ◽  
B. T. DONOVAN
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Foreign Bodies ◽  
Glass Beads ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Blood Samples ◽  
Progesterone Secretion ◽  
Prostaglandin F

SUMMARY The response of the guinea-pig corpus luteum to the luteolytic influence of glass beads placed in the uterus, or to prostaglandin administration, was followed by assay of the progesterone content of blood samples collected daily. Following the introduction of glass beads into the uterus early in the cycle, the secretion of progesterone was curtailed. Treatment with prostaglandin F2α over days 4–6 or 6–8 of the cycle temporarily depressed progesterone release without shortening the life of the corpora lutea. When the drug was administered over days 8–10, 10–12 or 12–14 the depression in progesterone was not followed by any recovery. These observations indicate that the response of the corpora lutea to a luteolytic influence changes during the oestrous cycle.

CYTOCHROME P-450 ACTIVITY IN SHEEP CORPORA LUTEA DURING THE OESTROUS CYCLE

1973 ◽  
Vol 58 (3) ◽  
pp. 493-501 ◽  
Author(s):  
E. R. SIMPSON ◽  
C. R. JEFCOATE ◽  
R. A. COLLETT ◽  
R. B. LAND
Keyword(s):  
Corpus Luteum ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Mitochondrial Cytochrome ◽  
Specific Content ◽  
Substrate Complex ◽  
Chain Cleavage ◽  
Binding Spectra ◽  
Two Parameters ◽  
Cytochrome P 450

SUMMARY Cytochrome P-450 of mitochondria from the ovine corpus luteum was examined on different days throughout the oestrous cycle. Most, if not all, of the mitochondrial cytochrome P-450 appeared to be of the type involved in cholesterol side-chain cleavage, as determined by steroid binding spectra. The content of mitochondrial cytochrome P-450 in the corpus luteum changed considerably throughout the cycle, and closely paralleled the rise and fall of plasma progesterone concentration; the correlation between these two parameters was 0·96. This was largely a reflection of the changes in weight of the corpus luteum throughout the cycle, since the specific content of cytochrome P-450 changed much less dramatically. The percentage of the mitochondrial cytochrome P-450 present as the cholesterol—substrate complex remained constant throughout the cycle at about 25–30% of the total.

Steroid concentrations in rat corpora lutea isolated during the oestrous cycle and pseudopregnancy: effect of induction of ovulation at dioestrus

1989 ◽  
Vol 120 (2) ◽  
pp. 325-330 ◽  
Author(s):  
J. Th. J. Uilenbroek ◽  
P. J. A. Woutersen ◽  
P. D. M. van der Vaart
Keyword(s):  
Pituitary Gland ◽  
Corpus Luteum ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Serum Concentrations ◽  
Kidney Capsule ◽  
Cervical Stimulation ◽  
Sensitive Method

ABSTRACT Corpora lutea could be identified under the dissection microscope up to 7 days after formation. They were isolated during the oestrous cycle and pseudopregnancy and the progesterone and 20α-OH-progesterone contents were compared with serum values of these steroids. The pattern of progesterone in serum resembled that found in the corpora lutea. However, the pattern of 20α-OH-progesterone concentrations in serum and corpora lutea were different. While 20α-OH-progesterone concentrations in the corpora lutea showed large variations during the cycle, changes in serum concentrations of 20α-OH-progesterone were relatively small. Measurement of hormone concentrations in isolated corpora lutea is therefore a sensitive method for studying corpus luteum activity. To study whether corpora lutea derived after ovulation of immature follicles showed deficient luteal activity, rats at dioestrus (2 days before pro-oestrus) were induced to ovulate by the injection of 10 IU human chorionic gonadotrophin (hCG) and subsequent luteal activity was studied by measuring hormone concentrations in the corpora lutea on day 5 of pseudopregnancy. Concentrations of progesterone, but not of 20α-OH-progesterone, in corpora lutea derived from follicles induced to ovulate at dioestrusday 1 were significantly lower than those in corpora lutea derived from follicles induced to ovulate at prooestrus. This difference was observed not only when pseudopregnancy was induced by cervical stimulation but also when it was induced by implantation of a pituitary gland under the kidney capsule. However, in the latter case, corpora lutea already present on the day of hCG injection also became activated. The present experiments demonstrate that by measuring hormone concentrations in isolated corpora lutea changes in luteal activity can be studied effectively. Moreover, it appears that corpora lutea derived from immature follicles contained less progesterone than those derived from fully mature follicles. Journal of Endocrinology (1989) 120, 325–330

Different effects of the antiprogesterone RU486 on progesterone secretion by the corpus luteum of rats with 4- and 5-day oestrous cycles

1992 ◽  
Vol 132 (1) ◽  
pp. 115-122 ◽  
Author(s):  
J. E. Sánchez-Criado ◽  
J. Th. J. Uilenbroek ◽  
B. Karels
Keyword(s):  
Corpus Luteum ◽  
Direct Effect ◽  
Reproductive Cycle ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Ovarian Weight ◽  
Progesterone Production ◽  
Progesterone Secretion

ABSTRACT Administration of the antiprogesterone RU486 (2 mg/day) for 14 days to rats with a 5-day reproductive cycle resulted in an increase in both ovarian and pituitary weight in contrast with rats with a 4-day oestrous cycle. Luteal progesterone production decreased earlier in 4-day than in 5-day cyclic rats. Treatment of 5-day cyclic rats with antiprogesterone from the day of metoestrus onwards resulted in the advancement of the preovulatory prolactin surge by 24 h. Progesterone production by the corpus luteum was, however, not affected, indicating that in 5-day cyclic rats the corpora lutea are still functionally active at the time of the preovulatory surge of prolactin. They become, therefore, stimulated both in size and progesterone production. In contrast, the corpora lutea in 4-day cyclic rats are functionally inactive at the time of the preovulatory surge of prolactin, and prolactin acts luteolytically. In conclusion, the advancement of the preovulatory surge of prolactin by 24 h accounts, at least in part, for the increase in ovarian weight in 5-day cyclic rats after treatment with antiprogesterone. The results of these experiments do not agree with a direct effect of the antiprogesterone RU486 on progesterone secretion by the corpus luteum. Journal of Endocrinology (1992) 132, 115–122

Insulin-like growth factor I receptor mRNA and protein expression in pig corpora lutea

Reproduction ◽  
2000 ◽  
pp. 109-114 ◽  
Author(s):  
Z Ge ◽  
WE Nicholson ◽  
DM Plotner ◽  
CE Farin ◽  
JE Gadsby
Keyword(s):  
Growth Factor ◽  
Corpus Luteum ◽  
Oestrous Cycle ◽  
Receptor Protein ◽  
Corpora Lutea ◽  
Western Blots ◽  
Luteal Cells ◽  
Factor I ◽  
Receptor Mrna ◽  
Igf I

Insulin-like growth factor I (IGF-I) is believed to play a luteotrophic role in the pig corpus luteum during the oestrous cycle. Since the actions of IGF-I in target tissues are mediated by the type I IGF receptor, the concentrations of IGF-I receptor mRNA and protein were examined in pig corpora lutea at different stages of the oestrous cycle. Corpora lutea were collected from normally cyclic gilts on days 4, 7, 10, 13, 15 and 16 of the oestrous cycle (n = 4 animals per day). Corpora lutea on days 7, 10 and 13 were dissociated with collagenase, and large and small luteal cell sub-populations were separated by elutriation. Northern and slot blots were used to examine mRNA, and western blots were used to measure the concentrations of IGF-I receptor protein in the pig corpus luteum. On northern blots, luteal IGF-I receptor mRNA was present as a single 11 kb transcript. The slot blots showed that the steady state expression of IGF-I receptor mRNA increased significantly (P < 0.05) from its lowest value on day 4, to reach a maximum on days 13-16. IGF-I receptor mRNA was also expressed to a greater extent in large compared with small luteal cells (P < 0.05). On western blots, IGF-I receptor appeared as a 95 kDa protein band (beta-subunit) and IGF-I receptor protein concentrations were significantly higher (P < 0.05) on days 4-10 than on days 13-16. Finally, large luteal cells appeared to contain more IGF-I receptor protein than the small luteal cells. In conclusion, since IGF-I receptor was detected in the pig corpus luteum, it is a likely target tissue for IGF-I, especially during the early luteal phase. Furthermore, IGF-I receptor was localized primarily on large luteal cells, thus it is hypothesized that IGF-I may play a paracrine role in the pig corpus luteum.

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