Equine ovarian aromatase: evidence for a species specificity

1993 ◽  
Vol 71 (5-6) ◽  
pp. 296-302 ◽  
Author(s):  
Hakima Amri ◽  
Jean-Luc Gaillard ◽  
Ihsan Al-Timimi ◽  
Pierre Silberzahn
Keyword(s):  
Corpus Luteum ◽  
Granulosa Cells ◽  
Species Specificity ◽  
Estrogen Synthetase

Mare granulosa cells and cyclic corpus luteum microsomes are reported to aromatize 19-norandrogens more efficiently than androgens. However, 16α-hydroxytestosterone and epitestosterone were not aromatized by the equine corpus luteum microsomal estrogen synthetase. These results indicate that the equine aromatase system would be different from the human placental microsomal estrogen synthetase, which aromatizes 16α-hydroxyandrogens and epitestosterone but not 19-norandrogens. Furthermore, our data show that the rates of aromatization of androgens and 19-norandrogens were not additive and that 19-norandrogens competitively inhibited the aromatization of androgens, suggesting that a single enzymic system would be involved in the aromatization of androstenedione, 19-norandrostenedione, testosterone, and 19-nortestosterone. Our findings, which are identical to those previously reported for stallion testis and mare placental estrogen synthetases, provide evidence for a strong species specificity of the equine aromatase system.Key words: equine, cyclic corpus luteum, aromatase, androgens, 19-norandrogens.

scholarly journals Secreted Protein, Acidic and Rich in Cysteine (SPARC) and Thrombospondin in the Developing Follicle and Corpus Luteum of the Rat

1998 ◽  
Vol 46 (9) ◽  
pp. 1043-1049 ◽  
Author(s):  
P. Bagavandoss ◽  
E. Helene Sage ◽  
Robert B. Vernon
Keyword(s):  
Corpus Luteum ◽  
Granulosa Cells ◽  
Molecular Mechanisms ◽  
Basement Membranes ◽  
Oocyte Nucleus ◽  
Variable Degree ◽  
Matricellular Proteins ◽  
Luteal Cells ◽  
Postovulatory Follicle ◽  
Thecal Cells

In adult mammals, growth of new vasculature from extant blood vessels (angiogenesis) is rare in the absence of pathology. However, nonpathogenic angiogenesis occurs in the cycling ovary when the avascular postovulatory follicle transforms into a highly vascularized corpus luteum (CL). To improve our understanding of molecular mechanisms that regulate nonpathogenic vascular growth, we characterized the expression of two secreted matricellular proteins associated with angiogenesis, SPARC and thrombospondin (TSP), in postovulatory preluteal follicles and CL of hormone-primed immature rats. By indirect immunofluorescence with specific antibodies, we found SPARC in the cytoplasm of granulosa cells and thecal cells of preluteal follicles, in connective tissue cells of the ovarian interstitium, and in the oocyte nucleus. Administration of a luteinizing stimulus (chorionic gonadotropin) increased the expression of SPARC in granulosa cells. TSP was prominent in the basement membranes of growing follicles. Many cells in the early vascularizing CL expressed both SPARC and TSP. Neovascularization of CL was accompanied by expression of SPARC in nascent vessels and concentration of TSP in central avascular areas. In mature CL, steroidogenic luteal cells expressed both SPARC and TSP. Luteal cells of regressing CL retained SPARC to a variable degree but did not express TSP. The observed changes in expression of SPARC and TSP during development of the CL support distinct roles for these matricellular proteins in nonpathological morphogenesis and angiogenesis.

scholarly journals Terminal differentiation of human granulosa cells as luteinization is reversed by activin-A through silencing of Jnk pathway

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Gamze Bildik ◽  
Nazli Akin ◽  
Yashar Esmaeilian ◽  
Francesko Hela ◽  
Ceren Sultan Yildiz ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Signaling Pathway ◽  
Granulosa Cells ◽  
Molecular Mechanisms ◽  
Terminal Differentiation ◽  
Reproductive Technologies ◽  
Activin A ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Jnk Signaling Pathway

Abstract Molecular mechanisms underlying luteinization (terminal differentiation of granulosa and theca cells after ovulation) and luteolysis (demise of corpus luteum) are poorly understood in human ovary. Here we report that activin-A, after binding to its cognate receptors induces a functional luteolytic state and reverses luteinization phenotype by downregulating the expression of the steroidogenic enzymes, LH receptor and VEGF and reducing estradiol (E2) progesterone (P4) production and upregulating FSH receptor and cyclin D1 expression in human primary luteinized granulosa cells. Further, this action of activin-A involves downregulation of JNK signaling pathway and is opposite to that of human chorionic gonadotropin (hCG), which acts as a luteotropic hormone and improves luteal function through the activation of JNK pathway in the same cell type. Reversal of luteinization phenotype in luteal granulosa cells by activin-A potentially makes this hormone an attractive candidate for use under certain clinical situations, where induction of luteolysis and rapid reduction of endogenous sex steroid levels are beneficial such as ovarian hyperstimulation syndrome (OHSS), in which the ovaries hyper-respond to gonadotropin stimulation by producing too many growing follicles along with development of ascites, pleural effusion, and hemo-concentrations as a result of increased vascular permeability and leakage of intravascular volume into third spaces. Our work unveils a previously undefined role for activin-A and JNK signaling pathway in human corpus luteum biology, that might have a direct clinical impact in assisted reproductive technologies.

107 Localization of Kisspeptin Immunoreactivity in the Cat Ovary on Different Reproductive Stages

2018 ◽  
Vol 30 (1) ◽  
pp. 193
Author(s):  
P. Tanyapanyachon ◽  
O. Amelkina ◽  
K. Chatdarong
Keyword(s):  
Corpus Luteum ◽  
Granulosa Cells ◽  
Ovarian Surface Epithelium ◽  
Domestic Cat ◽  
Primary Antibody ◽  
Surface Epithelium ◽  
Domestic Cats ◽  
Luteal Cells ◽  
Theca Cells ◽  
Steroidogenic Cells

Kisspeptin (Kp) is considered one of the main regulators of the reproductive axis, exerting its effects via stimulating GnRH expression in the hypothalamus. Apart from its central localization in the hypothalamus, the presence of Kp has been reported in the ovary, with possible local function. To date, very little is known about the ovarian Kp in the domestic cat. Therefore, our aim was to investigate the presence and localization of Kp at different reproductive stages in domestic cat ovaries. Twenty ovaries were collected from free-ranging domestic cats (body weight 2.7–4.5 kg) after routine ovariohysterectomy. Reproductive stages were classified by ovarian gross morphology, vaginal cytology, and blood progesterone level. Ovarian samples were grouped into inactive (n = 6), follicular (n = 8), and luteal stages (n = 6). Tissues were fixed in 4% paraformaldehyde and processed routinely. Immunohistochemistry was performed using polyclonal rabbit Kp-10 primary antibody (AB9754; Millipore, Billerica, MA, USA) at 1:500 at 4°C overnight. Immunoreactive cells were identified by avidin-biotin-peroxidase system. Rat hypothalamic tissue was used as a positive control. Primary antibody was substituted with PBS and normal rabbit IgG as the negative and isotypic negative controls, respectively. In addition, primary antibody was incubated with metastin overnight and applied for preabsorption test. Negative, isotypic negative, and preabsorption tests showed no staining. Immunoreactive Kp was detected in the ovaries of all reproductive stages with no obvious changes in localization or intensity of staining between stages. Kisspeptin was present in the cytoplasm of oocytes, granulosa cells, and theca cells of preantral (primordial, primary, and secondary) follicles and antral follicles. Interestingly, in most follicles, Kp staining was more prominent in theca cells and oocytes compared with granulosa cells. In corpus luteum, Kp was localised in the cytoplasm of luteal cells, with more intense staining on the periphery of corpus luteum compared with the middle in 3 luteal samples, whereas the rest of the samples demonstrated homogeneous staining distribution. Apart from oocytes and steroidogenic cells, Kp was also present in the cytoplasm of cells of the ovarian surface epithelium. Our study for the first time demonstrated the presence and localization of Kp in the ovary of the domestic cats. The localization of Kp in the cat oocyte is similar to previous reports on hamsters and dogs, indicating a possible function in oocyte development. The staining in steroidogenic cells, mainly theca cells and luteal cells, is in good agreement with studies on hamsters, rats, humans, and marmosets, suggesting the possible local involvement of Kp in steroidogenesis. In addition, Kp staining in the ovarian surface epithelium suggests a possible role in the ovarian remodeling after ovulatory defects, as reported in humans and marmosets. This research was funded by the RGJ PhD program PHD/01882556; RG 7/2559.

Change of Protein Patterns in Granulosa Cells and Corpus Luteum during the Ovarian Cycle in Cows

2013 ◽  
Vol 37 (3) ◽  
pp. 149-154
Author(s):  
Eun-Ji Song ◽  
◽  
Yong-Seung Lee ◽  
Sang-Hee Lee ◽  
Han-jun Yoo ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Granulosa Cells ◽  
Ovarian Cycle ◽  
Protein Patterns

scholarly journals The Molecular Control of Corpus Luteum Formation, Function, and Regression

2007 ◽  
Vol 28 (1) ◽  
pp. 117-149 ◽  
Author(s):  
Carlos Stocco ◽  
Carlos Telleria ◽  
Geula Gibori
Keyword(s):  
Corpus Luteum ◽  
Granulosa Cells ◽  
Endocrine Glands ◽  
Checks And Balances ◽  
Molecular Control ◽  
Current Review ◽  
Molecular Events ◽  
Formation Function ◽  
Functional Features

The corpus luteum (CL) is one of the few endocrine glands that forms from the remains of another organ and whose function and survival are limited in scope and time. The CL is the site of rapid remodeling, growth, differentiation, and death of cells originating from granulosa, theca, capillaries, and fibroblasts. The apparent raison d’etre of the CL is the production of progesterone, and all the structural and functional features of this gland are geared toward this end. Because of its unique importance for successful pregnancies, the mammals have evolved a complex series of checks and balances that maintains progesterone at appropriate levels throughout gestation. The formation, maintenance, regression, and steroidogenesis of the CL are among the most significant and closely regulated events in mammalian reproduction. During pregnancy, the fate of the CL depends on the interplay of ovarian, pituitary, and placental regulators. At the end of its life span, the CL undergoes a process of regression leading to its disappearance from the ovary and allowing the initiation of a new cycle. The generation of transgenic, knockout and knockin mice and the development of innovative technologies have revealed a novel role of several molecules in the reprogramming of granulosa cells into luteal cells and in the hormonal and molecular control of the function and demise of the CL. The current review highlights our knowledge on these key molecular events in rodents.

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