scholarly journals METABOLIC AND ULTRASTRUCTURAL CHANGES IN THE FROG OVARIAN FOLLICLE IN RESPONSE TO PITUITARY STIMULATION

1970 ◽  
Vol 46 (3) ◽  
pp. 491-504 ◽  
Author(s):  
John Walberg Anderson ◽  
Milton B. Yatvin
Keyword(s):  
Epithelial Cells ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Ovarian Tissue ◽  
Ovarian Follicle ◽  
Ovarian Follicles ◽  
Ultrastructural Changes ◽  
Surface Epithelium

Frog ovarian fragments were prevented from ovulating in vitro by the addition of actinomycin D up to 3 hr following pituitary stimulation; but addition of Actinomycin D 6 hr after stimulation was far less effective. Puromycin, on the other hand, effectively inhibited ovulation when added as late as 6 hr after pituitary stimulation. Although actinomycin D reduced uptake of uridine-3H, and puromycin reduced uptake of leucine-3H and lysine-14 by pituitary-stimulated ovarian tissue minus oocytes (OTMO) in vitro, it was found that pituitary stimulation did not significantly increase uptake of these compounds by OTMO. Radioautographs of ovarian follicles fixed 6 hr after the addition of pituitary extract and uridine-3H in vitro revealed increased RNA synthesis in the peritoneal surface epithelium, compared with unstimulated controls, while the ovarian sac epithelium showed no increase. Gross ultrastructural changes occurred in the peritoneal area of ovarian follicles following pituitary stimulation in vivo, including loss of collagen fibrils, and general disorganization of the connective tissue theca. Changes in the rough endoplasmic reticulum of the peritoneal epithelial cells, while frequently encountered, were less pronounced. None of these changes was observed in the ovarian sac area, or in the interfollicular region. The above data are consistent with the hypothesis that pituitary stimulation of the frog ovary results in increased synthesis of RNA and protein by the peritoneal epithelial cells, and that the protein may be collagenase.

Synthesis of acid-soluble spore proteins by Bacillus subtilis

1982 ◽  
Vol 152 (3) ◽  
pp. 1117-1125
Author(s):  
J M Leventhal ◽  
G H Chambliss
Keyword(s):  
Bacillus Subtilis ◽  
Maximum Rate ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Spore Proteins ◽  
Major Acid

The major acid-soluble spore proteins (ASSPs) of Bacillus subtilis were detected by immunoprecipitation of radioactively labeled in vitro- and in vivo-synthesized proteins. ASSP synthesis in vivo began 2 h after the initiation of sporulation (t2) and reached its maximum rate at t7. This corresponded to the time of synthesis of mRNA that stimulated the maximum rate of ASSP synthesis in vitro. Under the set of conditions used in these experiments, protease synthesis began near t0, alkaline phosphatase synthesis began at about t2, and refractile spores were first observed between t7 and t8. In vivo- and in vitro-synthesized ASSPs comigrated in sodium dodecyl sulfate-polyacrylamide gels. Their molecular weights were 4,600 (alpha and beta) and 11,000 (gamma). The average half-life of the ASSP messages was 11 min when either rifampin (10 micrograms/ml) or actinomycin D (1 microgram/ml) was used to inhibit RNA synthesis.

ACTION OF KI, THYROXINE AND CYCLIC AMP ON [3H]URIDINE INCORPORATION INTO THE RNA OF THYROID SLICES

1976 ◽  
Vol 83 (2) ◽  
pp. 313-320 ◽  
Author(s):  
Mario A. Pisarev ◽  
Leonardo O. Aiello ◽  
Diana L. Kleiman de Pisarev
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Action ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Protein Biosynthesis ◽  
Rna Degradation ◽  
Precursor Pool ◽  
Rna Precursor

ABSTRACT Potassium iodide (KI) has been shown to impair thyroid protein biosynthesis both in vivo and in vitro. The present study was performed in order to clarify its mechanism of action. Ribonucleic acid (RNA) synthesis was studied in beef thyroid slices with either [32P] or [3H]-uridine as labelled precursors. Both KI and thyroxine (T4) at 10−5 m significantly decreased RNA labelling under our conditions. In other experiments RNA degradation was examined in pulse-labelled and actinomycin D-treated slices. KI did not modify the degradation of the [3H]-RNA thus indicating that it interferes with the biosynthesis rather than with the degradation of RNA. Taking the perchloric acid soluble radioactivity as a rough index of the precursor pool the present results would indicate an action at this level. Both KClO4 and methylmercapto-imidazole relieved the gland from the inhibitory action of KI, supporting the view that an intracellular and organified form of iodine is responsible for this action. Since T4 also reproduced the effects of KI on RNA synthesis we would like to propose iodothyronines as the intermediates of this action. Cyclic AMP has been shown to stimulate thyroid protein biosynthesis. The present results demonstrate an action at the RNA level. Cyclic AMP increased both the PCA-soluble and RNA-linked radioactivity, thus suggesting an effect at the RNA precursor pool. KI at 10−5 m blocked the action of 2 mm cyclic AMP.

scholarly journals Epidermal growth factor reduces autophagy in intestinal epithelium and in the rat model of necrotizing enterocolitis

2010 ◽  
Vol 299 (3) ◽  
pp. G614-G622 ◽  
Author(s):  
Andrew A. Maynard ◽  
Katerina Dvorak ◽  
Ludmila Khailova ◽  
Holly Dobrenen ◽  
Kelly M. Arganbright ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epithelial Cells ◽  
Necrotizing Enterocolitis ◽  
Intestinal Epithelium ◽  
Beclin 1 ◽  
Ultrastructural Changes ◽  
Epidermal Growth

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Epidermal growth factor (EGF) is one of the most promising candidates in NEC prophylaxis. Autophagy regulates cell homeostasis, but uncontrolled activation of autophagy may lead to cellular injury. The aim was to evaluate the effects of EGF on intestinal autophagy in epithelial cells and in the rat NEC model and measure autophagy in NEC patients. Intestinal epithelial cells (IEC-6) and the rat NEC model were used to study the effect of EGF on intestinal autophagy. Protein levels of Beclin 1 and LC3II were measured in the intestinal epithelium in both in vivo and in vitro models. Ultrastructural changes in intestinal epithelium were studied by electron microscopy. Expression of Beclin 1, LC3II, and p62 protein was evaluated in biopsies from NEC patients. Autophagy was induced in IEC-6 cells and inhibited by adding EGF into the culture. In the rat NEC model, EGF treatment of NEC reduced expression of Beclin 1 and LC3II in ileal epithelium. Morphologically, typical signs of autophagy were observed in the epithelium of the NEC group, but not in the EGF group. A strong signal for Beclin 1 and LC3II was detected in the intestine from patients with NEC. Autophagy is activated in the intestinal epithelium of NEC patients and in the ileum of NEC rats. Supplementation of EGF blocks intestinal autophagy in both in vivo and in vitro conditions. Results from this study indicate that EGF-mediated protection against NEC injury is associated with regulation of intestinal autophagy.

scholarly journals Initial and Cyclic Recruitment of Ovarian Follicles*

2000 ◽  
Vol 21 (2) ◽  
pp. 200-214 ◽  
Author(s):  
Elizabeth A. McGee ◽  
Aaron J. W. Hsueh
Keyword(s):  
Ovarian Follicle ◽  
Ovarian Follicles ◽  
Follicle Development ◽  
Ovarian Follicle Development ◽  
Branching Points ◽  
Reproductive Techniques ◽  
Recruitment And Selection ◽  
Cyclic Recruitment

Abstract Mammalian ovaries consist of follicles as basic functional units. The total number of ovarian follicles is determined early in life, and the depletion of this pool leads to reproductive senescence. Each follicle develops to either ovulate or, more likely, to undergo degeneration. The dynamics of ovarian follicle development have interested endocrinologists and developmental biologists for many years. With the advent of assisted reproductive techniques in humans, the possibility of regulating follicle development in vivo and in vitro has gained clinical relevance. In this review, we focus upon key branching points during the development of ovarian follicles as well as factors involved in determining the eventual destiny of individual follicles. We discuss inconsistencies in the literature regarding the definitions of follicle recruitment and selection and propose to name the two major steps of follicle development as initial and cyclic recruitment, respectively. Because some of these disparities have arisen due to differences in the animal systems studied, we also compare the development of the ovarian follicles of both humans and rats. We also review the status of knowledge of several puzzling clinical issues that may provide important clues toward unlocking the mechanisms of follicle development.

scholarly journals INTRACELLULAR SYNTHESIS, TRANSPORT, AND PACKAGING OF PROTEINACEOUS YOLK IN OOCYTES OF ORCONECTES IMMUNIS

1972 ◽  
Vol 52 (2) ◽  
pp. 420-437 ◽  
Author(s):  
L. R. Ganion ◽  
R. G. Kessel
Keyword(s):  
Amino Acids ◽  
Endoplasmic Reticulum ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Maternal Blood ◽  
Blood Proteins ◽  
Yolk Granules ◽  
Early Phases

The incorporation of leucine-3H into either ovarian or oocyte proteins occurs throughout vitellogenesis, but is at a maximum during early phases of this process. The labeling of ovarian and oocyte proteins is inhibited with cycloheximide. Oocytes are permeable to actinomycin D, and this drug does not affect the incorporation of amino acids into oocyte proteins but does block oocyte RNA synthesis. By means of both light microscope and high resolution radioautography, it has been demonstrated that the initial incorporation of leucine-3H under both in vitro and in vivo conditions occurs in elements of the rough-surfaced endoplasmic reticulum in the oocyte. Under pulse-chase conditions, the label subsequently becomes associated with intracisternal (precursor yolk) granules now aggregated within the cisternae of the connected smooth-surfaced endoplasmic reticulum. By 7 days, mature yolk globules are extensively labeled. The results of experiments designed to assess the possible contribution of maternal blood proteins to yolk deposition indicate that such a contribution is minimal. It is concluded that the crayfish oocyte is programmed for and capable of synthesizing the massive store of proteinaceous yolk present in the egg at the end of oogenesis.

scholarly journals Anti-Müllerian Hormone Attenuates the Effects of FSH on Follicle Development in the Mouse Ovary

Endocrinology ◽  
2001 ◽  
Vol 142 (11) ◽  
pp. 4891-4899 ◽  
Author(s):  
Alexandra L. L. Durlinger ◽  
Maria J. G. Gruijters ◽  
Piet Kramer ◽  
Bas Karels ◽  
T. Rajendra Kumar ◽  
...  
Keyword(s):  
Ovarian Follicle ◽  
Inhibitory Effect ◽  
Ovarian Follicles ◽  
Follicle Development ◽  
Wild Type ◽  
Follicle Growth ◽  
Primordial Follicles ◽  
Ovarian Follicle Development

Abstract Although ovarian follicle growth is under the influence of many growth factors and hormones of which FSH remains one of the most prominent regulators. Therefore, factors affecting the sensitivity of ovarian follicles to FSH are also important for follicle growth. The aim of the present study was to investigate whether anti-Müllerian hormone (AMH) has an inhibitory effect on follicle growth by decreasing the sensitivity of ovarian follicles to FSH. Furthermore, the combined action of AMH and FSH on ovarian follicle development was examined. Three different experiments were performed. Using an in vitro follicle culture system it was shown that FSH-stimulated preantral follicle growth is attenuated in the presence of AMH. This observation was confirmed by an in vivo experiment showing that in immature AMH-deficient females, more follicles start to grow under the influence of exogenous FSH than in their wild-type littermates. In a third experiment, examination of the follicle population of 4-month-old wild-type, FSHβ-, AMH-, and AMH-/FSHβ-deficient females revealed that loss of FSH expression has no impact on the number of primordial and preantral follicles, but the loss of inhibitory action of AMH on the recruitment of primordial follicles in AMH-deficient mice is increased in the absence of FSH. In conclusion, these studies show that AMH inhibits FSH-stimulated follicle growth in the mouse, suggesting that AMH is one of the factors determining the sensitivity of ovarian follicles for FSH and that AMH is a dominant regulator of early follicle growth.

scholarly journals Distinct Signaling Pathways Distinguish in vivo From in vitro Growth in Murine Ovarian Follicle Activation and Maturation

2021 ◽  
Vol 9 ◽  
Author(s):  
Mahboobeh Amoushahi ◽  
Karin Lykke-Hartmann
Keyword(s):  
Ovarian Tissue ◽  
Ovarian Follicle ◽  
Primordial Follicle ◽  
Ovarian Tissue Cryopreservation ◽  
Ros Production ◽  
Primordial Follicles ◽  
Expression Of Genes ◽  
Follicle Activation

Women with cancer and low ovarian reserves face serious challenges in infertility treatment. Ovarian tissue cryopreservation is currently used for such patients to preserve fertility. One major challenge is the activation of dormant ovarian follicles, which is hampered by our limited biological understanding of molecular determinants that activate dormant follicles and help maintain healthy follicles during growth. Here, we investigated the transcriptomes of oocytes isolated from dormant (primordial) and activated (primary) follicles under in vivo and in vitro conditions. We compared the biological relevance of the initial molecular markers of mature metaphase II (MII) oocytes developed in vivo or in vitro. The expression levels of genes involved in the cell cycle, signal transduction, and Wnt signaling were highly enriched in oocytes from primary follicles and MII oocytes. Interestingly, we detected strong downregulation of the expression of genes involved in mitochondrial and reactive oxygen species (ROS) production in oocytes from primordial follicles, in contrast to oocytes from primary follicles and MII oocytes. Our results showed a dynamic pattern in mitochondrial and ROS production-related genes, emphasizing their important role(s) in primordial follicle activation and oocyte maturation. The transcriptome of MII oocytes showed a major divergence from that of oocytes of primordial and primary follicles.

scholarly journals Ribonucleic acid synthesis in vitro in primary spermatocytes isolated from rat testis

1977 ◽  
Vol 168 (1) ◽  
pp. 23-31 ◽  
Author(s):  
J. Anton Grootegoed ◽  
Anne H. Grollé-Hey ◽  
Focko F. G. Rommerts ◽  
Henk J. Van Der Molen
Keyword(s):  
Electrophoretic Mobility ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Marked Change ◽  
Acid Synthesis ◽  
Specific Pattern ◽  
28S Rrna ◽  
Phenol Extraction

The incorporation of [3H]uridine into RNA was studied quantitatively (by incorporation of [3H]uridine into acid-precipitable material) and qualitatively (by phenol extraction and electrophoretic separation of RNA in polyacrylamide gels) in preparations enriched in primary spermatocytes, obtained from testes of rats 26 or 32 days old. The rate of incorporation of [3H]uridine into RNA of isolated spermatocytes was constant during the first 8h of incubation, after which it decreased, but the decreased rate of incorporation was not reflected in a marked change in electrophoretic profiles of labelled RNA. In isolated spermatocytes, [3H]uridine was incorporated mainly into heterogeneous RNA with a low electrophoretic mobility. Most of this RNA was labile, as shown when further RNA synthesis was inhibited with actinomycin D. Spermatocytes in vivo also synthesized heterogeneous RNA with a low electrophoretic mobility. A low rate of incorporation of [3H]uridine into rRNA of isolated spermatocytes was observed. The cleavage of 32S precursor rRNA to 28S rRNA was probably retarded in spermatocytes in vitro as well as in vivo. RNA synthesis by preparations enriched in early spermatids or Sertoli cells was qualitatatively different from RNA synthesis by the spermatocyte preparations. It is concluded that isolated primary spermatocytes maintain a specific pattern of RNA synthesis, which resembles RNA synthesis in spermatocytes in vivo. Therefore isolated spermatocytes of the rat can be used for studying the possible regulation of RNA synthesis during the meiotic prophase.

scholarly journals Regulation of fibrillins and modulators of TGFβ in fetal bovine and human ovaries

Reproduction ◽  
2016 ◽  
Vol 152 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Nicole A Bastian ◽  
Rosemary A Bayne ◽  
Katja Hummitzsch ◽  
Nicholas Hatzirodos ◽  
Wendy M Bonner ◽  
...  
Keyword(s):  
Growth Factors ◽  
Gestational Age ◽  
Ovarian Development ◽  
Ovarian Tissue ◽  
Culture Cell ◽  
Surface Epithelium ◽  
Tgfβ Signaling ◽  
Regulation Of Expression

Fibrillins 1–3 are stromal extracellular matrix proteins that play important roles in regulating TGFβ activity, which stimulates fibroblasts to proliferate and synthesize collagen. In the developing ovary, the action of stroma is initially necessary for the formation of ovigerous cords and subsequently for the formation of follicles and the surface epithelium of the ovary. FBN3 is highly expressed only in early ovarian development and then it declines. In contrast, FBN1 and 2 are upregulated in later ovarian development. We examined the expression of FBN1–3 in bovine and human fetal ovaries. We used cell dispersion and monolayer culture, cell passaging and tissue culture. Cells were treated with growth factors, hormones or inhibitors to assess the regulation of expression of FBN1–3. When bovine fetal ovarian tissue was cultured, FBN3 expression declined significantly. Treatment with TGFβ-1 increased FBN1 and FBN2 expression in bovine fibroblasts, but did not affect FBN3 expression. Additionally, in cultures of human fetal ovarian fibroblasts (9–17weeks gestational age), the expression of FBN1 and FBN2 increased with passage, whereas FBN3 dramatically decreased. Treatment with activin A and a TGFβ family signaling inhibitor, SB431542, differentially regulated the expression of a range of modulators of TGFβ signaling and of other growth factors in cultured human fetal ovarian fibroblasts suggesting that TGFβ signaling is differentially involved in the regulation of ovarian fibroblasts. Additionally, since the changes in FBN1–3 expression that occur in vitro are those that occur with increasing gestational age in vivo, we suggest that the fetal ovarian fibroblasts mature in vitro.

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