Quantitative changes in steroidogenic organelles in the corpus luteum of the pregnant rat in relation to progestin secretion on day 16 and in the morning and afternoon of day 22

Dharmarajan, Arun; Bruce, Neville; Waddell, Brendan J.

doi:10.1002/aja.1001900307

Cited by 5 publications

(5 citation statements)

References 31 publications

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“…It is known that when granulosa cells differentiate into corpus luteum, there is accompanying hypertrophy of the agranular endoplasmic reticulum, which seems to be further enhanced during pregnancy. This hypertrophy of the endoplasmic reticulum appears to reflect an increased demand for steroidogenesis and is also responsible for increased total protein observed in the pregnant corpus luteum [ 43 , 44 ]. Our finding that GPx8 is also present in granulosa lutein cells probably suggests that increased steroidogenesis in the corpus luteum needs protection against OS development.…”

Section: Discussionmentioning

confidence: 99%

GPx8 Expression in Rat Oocytes, Embryos, and Female Genital Organs During Preimplantation Period of Pregnancy

Mihálik

Kreheľová

Kovaříková

et al. 2020

IJMS

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This study aimed to detect the presence of glutathione peroxidase 8 (GPx8) in rat during preimplantation period of pregnancy. Females were killed on first (D1), third (D3), and fifth (D5) day of pregnancy. The presence of GPx8 in embryos was detected under the confocal microscope, the presence of GPx8 in genital organs was confirmed immunohistochemically, and the amount of GPx8 was determined using densitometry. We found that GPx8 is dispersed in the cytoplasm of oocytes, while after fertilization, it is concentrated in granules. From 4-cell stage till blastocyst, GPx8 reaction was found in the perinuclear region. In the ovary, GPx8 was seen in granulosa-lutein cells, in plasma of blood vessels, and inside Graafian follicles. In oviduct, GPx8 was detected in the plasma and in the extracellular matrix (ECM). Moreover, epithelial cells of isthmus were positive. In uterus, GPx8 was observed in the uterine glands, in the plasma, and in ECM. On D5, the enzyme disappeared from the uterine glands and appeared in fibroblasts. Densitometry revealed that the highest amount of GPx8 was on D1 and subsequently declined. To our knowledge, this is the first paper describing GPx8 presence in the oocytes, preimplantation embryos, and female genital organs in mammals. Our results improve the understanding of antioxidant enzymes presence during pregnancy in defense against oxidative stress, which is considered to be one of the main causes of infertility.

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Section: Discussionmentioning

confidence: 99%

GPx8 Expression in Rat Oocytes, Embryos, and Female Genital Organs During Preimplantation Period of Pregnancy

Mihálik

Kreheľová

Kovaříková

et al. 2020

IJMS

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“…We have recently shown that total progestin (progesterone plus 20a-hydroxypregn-4-en-3-one) secretion rates in the rat fall from 32 pglhr per ovary on day 16 to 10 pglhr per ovary on the morning (1100 hr) of day 22 (day 22 AM) and rise again to 23 pglhr per ovary in the afternoon (1500 hr) of the same day (day 22 PM). These changes are not accompanied by any comparable changes in CL volume (Waddell et al, 1989) or in the amount and surface areas of steroidogenic organelles (Dharmarajan et al, 1991). The present work therefore was carried out to test whether changes in transport structures would more closely reflect progestin secretion rates and the increase in total ovarian and CL blood flow observed over days 16 to 22 (Bruce et al, 1984).…”

Section: Introductionmentioning

confidence: 94%

“…These changes are not accompanied by any comparable changes in CL volume (Waddell et al, 1989) or in the amount and surface areas of steroidogenic organelles (Dharmarajan et al, 1991). The present work therefore was carried out to test whether changes in transport structures would more closely reflect progestin secretion rates and the increase in total ovarian and CL blood flow observed over days 16 to 22 (Bruce et al, 1984).…”

Section: Introductionmentioning

confidence: 94%

Changes in ultrastructure of transport systems and in rates of progestin secretion in the corpus luteum during late pregnancy in the rat

Dharmarajan¹,

Bruce²,

Waddell³

1991

Am. J. Anat.

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Morphometric studies have confirmed that the corpus luteum (CL) of the pregnant rat contains luteal cells with numerous microvilli which directly face an extensive network of sinusoidal capillaries. From this it has been suggested that extensive development of transport structures is necessary to support progesterone synthesis and secretion. The present study was carried out to determine whether these transport structures could be related quantitatively to different rates of total progestin (progesterone plus 20 alpha-hydroxypregn-4-en-3-one) secretion reported to be 32, 10, and 23 micrograms/hr per ovary on day 16 and the morning (AM) and afternoon (PM) of day 22, respectively. Histological analysis was carried out on two CL, fixed by immersion, from each of five rats, at each stage of gestation. The important findings to emerge were that when the progestin secretion rate was greater, there was a significant increase in surface specializations on the luteal cell and a thickening of the capillary walls. There was also a greater volume of interstitial space between luteal cells and capillaries. However, due to the development of microvilli and unevenness in the capillary wall, the physiological diffusion distance (harmonic distance) between luteal cell cytoplasm and blood was not increased. Collectively, these results show that changes in the rate of progestin secretion are accompanied by significant, although disproportionate, changes in transport structures and suggest that the latter are important in supporting luteal function.

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“…The corpus luteum (CL) is a fully differentiated structural and functional unit that undergoes apoptosis following the cyclic withdrawal of tropic support [6]. CL apoptosis is best characterized by the loss of steroidogenic potential [7,8] and luteal cell death [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Role of Tumor Necrosis Factor-Alpha and the Modulating Effect of the Caspases in Rat Corpus Luteum Apoptosis1

Abdo¹,

Hisheh²,

Dharmarajan³

2003

Biology of Reproduction

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Tumor necrosis factor-alpha (TNF␣) is a pleiotropic cytokine that has been implicated in apoptosis of many cell systems. However, the signal transduction of TNF␣ during the structural and functional regression of the corpus luteum (CL) is largely unknown. In this study, we investigate the role of TNF␣ in rat CL apoptosis and the involvement of monocyte chemoattractant protein-1 (MCP-1) and the modulating effect of the caspases in this process. An in vivo study of CL during pregnancy and postpartum using immunohistochemistry and Western blot analysis indicated that increases in TNF␣ correspond with luteal apoptosis approaching term (Day 22) and at postpartum (Day 3). CL apoptosis was further investigated using a whole-CL culture model of tropic withdrawal. An increase was observed in both low molecular weight (MW) DNA fragmentation and TUNEL staining from 0 h to 8 h in culture. CL apoptosis in vitro was associated with increased protein expression of both TNF␣ and MCP-1 as measured by immunohistochemistry and Western blot analysis. Using a whole-CL culture model, apoptosis was induced in vitro by TNF␣ as demonstrated by a dose-dependent increase in DNA fragmentation. Treatment of luteal cells with TNF␣ and both specific caspase inhibitors (Z-DEVD-FMK, Z-VEID-FMK, Z-IETD-FMK) or a general caspase inhibitor (Boc-D-FMK) prevented the effect of TNF␣. CL regression involves the apoptotic deletion of luteal cells; the results of this study suggestthat TNF␣ is possibly involved in this process. The observed increases in MCP-1 expression suggest the coordination of TNF␣ expression with the infiltration and activation of macrophages. Furthermore, the results demonstrate the importance of the caspases in the TNF␣ signal transduction pathway and suggest a hierarchy within the caspase family.

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Quantitative changes in steroidogenic organelles in the corpus luteum of the pregnant rat in relation to progestin secretion on day 16 and in the morning and afternoon of day 22

Cited by 5 publications

References 31 publications

GPx8 Expression in Rat Oocytes, Embryos, and Female Genital Organs During Preimplantation Period of Pregnancy

GPx8 Expression in Rat Oocytes, Embryos, and Female Genital Organs During Preimplantation Period of Pregnancy

Changes in ultrastructure of transport systems and in rates of progestin secretion in the corpus luteum during late pregnancy in the rat

Role of Tumor Necrosis Factor-Alpha and the Modulating Effect of the Caspases in Rat Corpus Luteum Apoptosis1

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