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The corpus luteum (CL) is a site of intense angiogenesis. Within a short period, this is followed either by controlled regression
of the microvascular tree in the non-fertile cycle, or maintenance and stabilisation of the new vasculature a conceptual cycle.
The molecular regulation of these diverse aspects is examined. The CL provides a unique model system in which to study the
cellular and molecular regulation of angiogenesis. Vascular endothelial growth factor (VEGF) has been found to have a major
role in the CL. By targeting its action at specific stages of the luteal phase in vivo by antagonists, profound inhibitory effects on luteal angiogenesis and function are observed. 相似文献
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The cyclic nature of the capillary bed in the corpus luteum offers a unique experimental model to examine the life cycle of
endothelial cells, involving discrete physiologically regulated steps of angiogenesis, blood vessel maturation and blood vessel
regression. The granulosa cells and theca cells of the developing antral follicle and the steroidogenic cells of the corpus
luteum produce and respond to angiogenic factors and vasoactive peptides. Following ovulation the neovascularization during
the early stages of corpus luteum development has been compared to the rapid angiogenesis observed during tumor formation.
On the other end of the spectrum, the microvascular endothelial cells are the first cells to undergo apoptosis at the onset
of corpus luteum regression. Important insights on the morphology and function of luteal endothelial cells have been gained
from a combination of in vitro and in vivo studies on endothelial cells. Endothelial cells communicate with cells comprising the functional unit of the corpus luteum,
i.e., other vascular cells, steroidogenic cells, and immune cells. This review is designed to provide an overview of the types
of endothelial cells present in the corpus luteum and their involvement in corpus luteum development and regression. Available
evidence indicates that microvascular endothelial cells of the corpus luteum are not alike, and may differ during the process
of angiogenesis and angioregression. The contributions of vasoactive peptides generated by the luteal endothelin-1 and the
renin-angiotensin systems are discussed in context with the function of endothelial cells during corpus luteum formation and
regression. The ability of two cytokines, tumor necrosis factor alpha and interferon gamma, are evaluated as paracrine mediators
of endothelial cell function during angioregression. Finally, chemokines are discussed as a vital endothelial cell secretory
products that contribute to the recruitment of eosinophils and macrophages. The review highlights areas for future investigation
of ovarian microvascular endothelial cells. The potential clinical applications of research directed on corpus luteum endothelial
cells are intriguing considering reproductive processes in which vascular dysfunctions may play a role such as ovarian failure,
polycystic ovary syndrome (PCOS), and ovarian hyperstimulation syndrome (OHSS). 相似文献
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Foley GL 《Theriogenology》1996,45(7):1413-1428
The corpus luteum (CL) is a transient endocrine organ which can manifest a number of pathologic conditions such as cysts, inflammation, adhesions, dysfunction and neoplasia. Luteal and follicular cysts are the most commonly encountered abnormalities and need to be distinguished from cysts within a normal CL. Inflammatory lesions are also frequently encountered and can be caused by viral, bacterial, or iatrogenic causes. If inflammation is severe, adhesions and subfertility/infertility can result. Luteal dysfunction is a broad classification of another pathologic condition encountered in the cow. Generally this results in abnormal production of progesterone or abnormal luteal lifespan resulting in infertility. Neoplasms are relatively rare in the CL but include both primary and metastatic tumors. Understanding the pathologic conditions that occur within the CL will allow a more accurate clinical assessment of these very dynamic endocrine structures. 相似文献
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Pituitary control of the ovine corpus luteum 总被引:1,自引:0,他引:1
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Takiguchi S Sugino N Esato K Karube-Harada A Sakata A Nakamura Y Ishikawa H Kato H 《Biology of reproduction》2004,70(2):313-318
Apoptosis contributes to luteal regression in many species. In the postpartum rat, there are two different types of corpora lutea (CL) in the ovary: CL of pregnancy (CLP) and newly formed CL (NCL). To investigate the regulation of apoptosis in the two different types of CL during luteal regression, apoptosis and caspase-3 activity were examined in the CL obtained on Days 7, 15, and 21 of pregnancy and Days 0, 1, 3, 5, 7, and 9 postpartum. Furthermore, the effect of lactation on apoptosis in the CL was examined in two groups of postpartum rats: lactating rats that nurse more than 10 pups, and nonlactating rats that nurse no pups. Apoptotic cells were detected after Day 21 of pregnancy. In the CLP, remarkable increases in the number of apoptotic cells on Days 5 and 9 postpartum were observed in nonlactating rats (P < 0.01), but not in lactating rats. Changes in caspase-3 activity in the CLP were not consistent with those in number of apoptotic cells. In the NCL, an increase in apoptosis was found only on Day 5 postpartum in nonlactating rats (P < 0.01), but not in lactating rats. Changes in caspase-3 activity in the NCL were consistent with those in number of apoptotic cells. In conclusion, apoptosis is, at least in part, involved in luteal regression after parturition, and lactation appears to inhibit apoptosis. This study also suggests the presence of a caspase-3-independent mechanism for apoptosis in CLP regression in the rat. 相似文献
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The synthesis of progesterone by the corpus luteum is essential for the establishment and maintenance of early pregnancy.
Regulation of luteal steroidogenesis can be broken down into three major events; luteinization (i.e., conversion of an ovulatory
follicle), luteal regression, and pregnancy induced luteal maintenance/rescue. While the factors that control these events
and dictate the final steroid end products are widely varied among different species, the composition of the corpus luteum
(luteinized thecal and granulosa cells) and the enzymes and proteins involved in the steroidogenic pathway are relatively
similar among all species. The key factors involved in luteal steroidogenesis and several new exciting observations regarding
regulation of luteal steroidogenic function are discussed in this review. 相似文献
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Binding of follicle stimulating hormone (FSH) to a crude membrane fraction of bovine corpus luteum (CL) has been detected. This binding meets the usual criteria for a receptor based on specificity, time course of reaction and association constant (Ka = 8.5 x 10(10)M(-1)). Physiological studies with CL removed from heifers at specific times after estrus indicate that day-6 CL had the highest FSH binding. However, a correlation with physiological function was not obvious since some functional mid-cycle CL were high in progesterone and luteinizing hormone (LH) receptor but had nondetectable FSH receptor. Conversely, some late-cycle CL had low progesterone and LH receptor but significant quantities of FSH receptor. 相似文献
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Richard L. Stouffer Cecily V. Bishop Randy L. Bogan Fuhua Xu Jon D. Hennebold 《Reproductive biology》2013,13(4):259-271
The primate corpus luteum is a transient endocrine gland that differentiates from the ovulatory follicle midway through the ovarian (menstrual) cycle. Its formation and limited lifespan is critical for fertility, as luteal-derived progesterone is the essential steroid hormone required for embryo implantation and maintenance of intra-uterine pregnancy until the placenta develops. It is well-established that LH and the LH-like hormone, CG, are the vital luteotropic hormones during the menstrual cycle and early pregnancy, respectively. Recent advances, particularly through genome analyses and cellular studies, increased our understanding of various local factors and cellular processes associated with the development, maintenance and repression of the corpus luteum. These include paracrine or autocrine factors associated with angiogenesis (e.g., VEGF), and that mediate LH/CG actions (e.g., progesterone), or counteract luteotropic effects (i.e., local luteolysis; e.g., PGF2α). However, areas of mystery and controversy remain, particularly regarding the signals and events that initiate luteal regression in the non-fecund cycle. Novel approaches capable of gene “knockdown” or amplification”, in vivo as well as in vitro, should identify novel or underappreciated gene products that are regulated by or modulate LH/CG actions to control the functional lifespan of the primate corpus luteum. Further advances in our understanding of luteal physiology will help to improve or control fertility for purposes ranging from preservation of endangered primate species to designing novel ovary-based contraceptives and treating ovarian disorders in women. 相似文献
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Pate JL 《Theriogenology》1996,45(7):1381-1397
There is a growing body of evidence that intercellular communication is important in the regulation of luteal function. Although the nature of the interactions between small and large luteal cells are not yet clear, it seems likely that they do exist. Many of the substances to which luteal cells respond, such as prostaglandins, growth factors, oxytocin and progesterone, are produced locally. These substances may act as paracrine factors to modulate the response of luteal cells to hormonal signals. Endothelial cells also produce factors that can modify steroidogenesis, and luteal cell-stimulation of endothelial cell proliferation is necessary for the extensive angiogenesis that occurs during luteinization Finally, bidirectional intercellular communication likely occurs between luteal cells and resident immune cells. Immune cells produce cytokines that can modify progesterone and prostaglandin synthesis by luteal cells. Cytokines may also have direct cytotoxic effects on luteal cells, and dead cells are then phagocytized by resident macrophages. Also, factors secreted by luteal cells can serve as chemoattractants for immune cells, and can enhance or suppress immune cell functions. There is little doubt that intercellular communication within the corpus luteum is very complex. One must remember, however, that nearly all evidence collected thus far is based on in vitro studies. Eventually, technology will allow for study of these interactions in vivo, and may lead to new methods for control of luteal function. 相似文献
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To examine the factor affecting LH-induced progesterone production in ovine luteal slices, an experimental procedure was employed wherein each slice served as its own control. The role of microfilaments in steroidogenesis was studied in luteal slices treated with cytochalasin B (an inhibitor of microfilament function). Cytochalasin B treatment resulted in significant reduction of progesterone production by luteal slices in response to LH and the addition of serum to the medium did not alter this effect. The ability of luteal slices to respond to LH with increased progesterone secretion was restored when cytochalasin B was removed from the medium. Further studies indicated that inhibition of LH-induced progesterone production by treatment with cytochalasin B was not a result of a change in: 1) cyclic adenosine 3'-5'-monophosphate production in response to LH; 2) mitochondrial membrane permeability to cholesterol; or 3) activity of 3β-hydroxysteroid dehydrogenase, Δ5,Δ4-isomerase enzyme complex.The possibility existed that microfilaments were necessary for cholesterol transport to mitochondria in response to LH stimulation. However, mitochondrial cholesterol content was unchanged in response to LH in the presence or absence of aminoglutethimide (an inhibitor of cholesterol side-chain cleavage enzyme activity) as determined by uptake of 3H-cholesterol or total content determined by gas-liguid chromatography. Further, treatment with cytochalasin B had no effect on mitochondrial cholesterol content. These results suggest a role for microfilaments in LH-induced progesterone production at a point prior to the conversion of cholesterol to pregnenolone. 相似文献
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Shin-ichi Hayama Shinji Kamiya Atsuko Yamazaki Masayuki Daigo Hideo Nigi 《Primates; journal of primatology》1992,33(1):133-137
The present study examined the histochemistry of pigments in the corpus luteum of the ovaries of cynomolgus monkeys (Macaca fascicularis), Japanese monkeys (Macaca fuscata), and rhesus monkeys (Macaca mulatta). Yellowish brown pigments were found in the regressing corpus luteum cells. Histochemical studies revealed that these pigments
consisted of lipofuscin, the so-called age pigment. The findings obtained suggest that accumulation of lipofuscin might be
related to cellular aging of the corpus luteum. 相似文献
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Rescue of the corpus luteum from its programmed senescence maintains progesterone production required for pregnancy. In primates, chorionic gonadotropin produced by the developing conceptus acts as the primary luteotrophic signal. The purpose of this research was to assess corpus luteum rescue by examining changes in daily urinary progesterone metabolite levels during the first week after implantation. We determined the variability in progesterone metabolite profiles and evaluated its relationship to early pregnancy loss in 120 naturally conceived human pregnancies, including 43 early pregnancy losses. In other primates, an abrupt increase in the progesterone metabolite occurs at the time of implantation. This pattern occurred in an estimated 45% of the pregnancies in the present study. In the remaining pregnancies, there was a delayed rise (18%), neither a rise or decline (22%), or a decline (15%) during the week after implantation. The estimated rate of early pregnancy loss increased across these categories (from 5% loss with an abrupt rise at implantation to 100% loss with progesterone metabolite decline). Low urinary hCG levels in early pregnancy were significant determinants of a decline in postimplantation progesterone metabolite. However, preimplantation steroid metabolite levels were not significant, suggesting no inherent problem with the corpus luteum. Examination of individual progesterone metabolite profiles in relation to hCG profiles also indicated that few losses were caused by corpus luteum failure. Delineating the functional importance of an abrupt progesterone rise at the time of implantation may provide new strategies for promoting successful implantation in assisted reproduction. 相似文献
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Summary An electron-microscopic investigation, based on the suggestion that differences seen in progesterone levels under differing hormonal conditions might be reflected in the ultrastructural organisation of the lutein cells of the guinea-pig was undertaken. Comparisons were made between corpora lutea taken from animals during the normal oestrous cycle, pregnancy and lactation, and after hysterectomy or hypophysectomy.The lutein cells from the oestrous cycle corpus luteum appeared to be of two types, light and dark. The former were more numerous. The main difference between them lay in the arrangement of the endoplasmic reticulum. Lutein cells from corpora lutea (with the exception of the old degenerating corpora lutea) all contained well-developed agranular endoplasmic reticulum, little granular endoplasmic reticulum, several electron-dense lipid granules, lysosomal bodies which ranged from small spherical bodies to large autophagic vesicles and mitochondria. The mitochondria were numerous, and in the corpus luteum of pregnancy, they were closely associated with the parallel arrays of granular endoplasmic reticulum.With minor exceptions, the lutein cells of the guinea-pig present a strikingly uniform picture despite their hormonal condition.The manner in which this uniformity of ultrastructure may be related to observed differences in progesterone levels in the corpus luteum of the guinea-pig is discussed.Meat and Livestock Commission (MLC) Scholar.The authors wish to thank Dr. J. S. Perry for doing the surgery involved in this work and for the specimens of corpora lutea of hysterectomy. They are also grateful to him for his helpful discussions and interest throughout. 相似文献