Inter-relationships between nonapeptide hormones and cyclic nucleotides within cultured porcine granulosa cells

1996 ◽  
Vol 150 (2) ◽  
pp. 343-348 ◽  
Author(s):  
A V Sirotkin
Keyword(s):  
Granulosa Cells ◽  
Cyclic Nucleotides ◽  
Hormone Secretion ◽  
Feedback Mechanism ◽  
The Other ◽  
Vasopressin Release ◽  
Negative Feedback Mechanism ◽  
Other Hand ◽  
Porcine Granulosa Cells ◽  
Camp And Cgmp

Abstract The reciprocal control of nonapeptide hormone (oxytocin, vasopressin) and cyclic nucleotide (cAMP, cGMP) release by porcine granulosa cells was studied. In particular, the influence of vasopressin and oxytocin treatment (10–10 000 ng/ml) on basal and LH-induced cAMP and cGMP output, as well as the effects of dibutyryl cAMP (dbcAMP; cAMP analogue) and forskolin (a stimulator of cAMP formation; 0·1–1000 ng/ml) on vasopressin and oxytocin secretion by cultured porcine granulosa cells were examined. It was observed that the addition of arginine-8-vasopressin or oxytocin stimulated both cAMP and cGMP output from granulosa cells. Moreover, both vasopressin and oxytocin also increased LH-stimulated cAMP and cGMP release. On the other hand, both dbcAMP and forskolin decreased vasopressin secretion. Oxytocin release was stimulated under the influence of dbcAMP. The same stimulating effect occurred with forskolin given at a low dose (1 ng/ml), whilst higher doses of forskolin (10 or 1000 ng/ml) were inhibitory. The present observations demonstrate the reciprocal influence of nonapeptide hormones and cyclic nucleotides in porcine ovarian cells. Oxytocin and vasopressin, like LH, exert their action on the ovary via the activation of cAMP- and cGMP-dependent intracellular mechanisms. cAMP in turn inhibits vasopressin release through a negative feedback mechanism. On the other hand, a reciprocal stimulation of oxytocin and cAMP output in granulosa cells is suggested. Thus, cyclic nucleotides can be both regulators of nonapeptide hormone secretion and mediators of their action within porcine ovaries. Journal of Endocrinology (1996) 150, 343–348

Cyclic nucleotides regulate oocyte meiotic maturation and quality in mammals

2020 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Anumegha Gupta ◽  
Meenakshi Tiwari ◽  
Alka Sharma ◽  
Ashutosh N. Pandey ◽  
Pramod K. Yadav ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Cyclic Nucleotides ◽  
Polar Body ◽  
The Other ◽  
Meiotic Maturation ◽  
Fetal Life ◽  
Other Hand ◽  
Oocyte Meiosis ◽  
First Polar Body ◽  
High Level

Oocyte meiosis is a prolong series of events that are comprised several intermittent channels in mammals. Oocyte meiosis starts during fetal life and then gets arrested at diplotene stage of first meiotic prophase in follicular oocyte. The continuous transfer of cyclic adenosine 3’, 5’-monophosphate (cAMP) and cyclic guanosine 3’, 5’-monophosphate (cGMP) from encircling granulosa cells to the oocyte through gap junctions helps in the maintenance of their high level required to achieve the long-lasting diplotene arrest so-called germinal vesicle stage. Phosphodiesterase inhibitors have been used to elevate intracellular level of both cyclic nucleotides and prevent spontaneous resumption of meiosis in oocytes under in vitro culture conditions. On the other hand, disruption of gap junction either by pituitary gonadotropin or by physical removal of encircling granulosa cells interrupts transfer of these nucleotides to the oocyte. As a result, intraoocyte cAMP as well as cGMP levels are decreased drastically that initiate downstream pathways to destabilize maturation-promoting factor (MPF). The destabilized MPF initiates meiotic resumption from diplotene arrest in mammalian oocytes. Oocyte meiosis further progresses from metaphase I to metaphase II stage and extrudes first polar body to get converted into haploid female gamete at the time of ovulation. Indeed, high level of cAMP as well as cGMP levels maintains diplotene arrest for a long time in follicular oocytes. On the other hand, transient decrease of their levels drives resumption from diplotene arrest, thereby meiotic maturation process, which enables oocyte to achieve developmental competency. Any defect in this process directly affects oocyte quality and thereby reproductive outcome in mammals including human.

scholarly journals Transcriptional, Mitochondrial Activity, and Viability of Egyptian Buffalo’s Granulosa Cells In Vitro Cultured under Heat Elevation

2021 ◽  
Vol 11 (2) ◽  
pp. 193-201
Author(s):  
Nasser Ghanem ◽  
Marwa Said Faheem ◽  
Romysa Samy ◽  
Ashraf Hesham Barkawi
Keyword(s):  
Heat Stress ◽  
Granulosa Cells ◽  
Transcriptional Activity ◽  
The Other ◽  
Control Group ◽  
Mitochondrial Activity ◽  
Fluorescent Intensity ◽  
Stressed Group ◽  
Other Hand

It is documented that heat stress caused impairment on the reproductive performance of dairy animals. However, there are few reports that have focused on the molecular and intracellular responses of in vitro cultured buffalo granulosa cells during heat elevation. The present study was conducted to investigate the effect of heat elevation during in vitro culture of buffalo granulosa cells on their viability, quality, mitochondrial activity, and transcriptional activity. Granulosa cells were harvested after aspiration of cumulus-oocytes complexes that were collected from abattoir ovaries. The granulosa cells were cultured in vitro either at a normal physiological temperature suitable for oocyte maturation and embryo development (38.5°C) or exposed to the elevated temperature of 40.5°C on day 3 of culture (the first two days were for confluence) for two hours of culture then continued at 38.5°C up to day 7 of culture. The viability of granulosa cells was measured using trypan blue and quality was estimated by measuring the level of intracellular reactive oxygen species (ROS) on day 7. Moreover, metabolic activity was performed by measuring the fluorescent intensity of mitochondria. Moreover, transcriptional activity was done by profiling four selected candidate genes using quantitative real-time PCR. The results indicated that the granulosa cells viability rate significantly decreased in the heat stress group (25.1 ± 3.7), compared to the control group (36.6 ± 5.3) on confluence day (day 3). In addition, the viability rate on the last day of culture (day 7) decreased in heat stress, compared to control (83.7 ± 4.5 and 97.4 ± 0.4, respectively). On the other hand, there was a nonsignificant difference in ROS profile between the control (21.7*104 ± 1.3) and the heat-stressed group (15.7 ± 0.7) on day 7 of culture. However, the mitochondrial fluorescent intensity was higher in the control (21.9 ± 1.9) than in the heat-stressed group (15.4 ± 0.8) on day 7 of culture. The expression of cellular defense (HSF1) and apoptosis-inducing gene (P53) were significantly up-regulated in granulosa cells exposed to heat elevation, compared to the control group. On the other hand, the steroidogenesis-regulating gene (StAR) was down-regulated in granulosa cells cultured under heat shock, compared to the control group. In conclusion, heat stress reduced the viability of granulosa cells by inducing the expression of an apoptosis-related gene (P53) and compromised expression of genes regulating the steroid biosynthesis, which resulted in up-regulation of cell defense gene (HSF1) in an attempt to ameliorate the deleterious effect of heat stress on the biological activity of the granulosa cells.

Distribution of ornithine decarboxylase in ovaries of rat and hamster during pro-oestrus

1986 ◽  
Vol 113 (3) ◽  
pp. 403-409 ◽  
Author(s):  
Lo Persson ◽  
Karin Isaksson ◽  
Elsa Rosengren ◽  
Frank Sundler
Keyword(s):  
Ornithine Decarboxylase ◽  
Granulosa Cells ◽  
Physiological Function ◽  
The Other ◽  
Interstitial Tissue ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Other Hand ◽  
Rat Ovary ◽  
Rate Limiting

Abstract. The biosynthesis of polyamines is dramatically increased in the ovaries of rat and hamster during the evening of pro-oestrus. In an attempt to shed some light on the physiological function of this biosynthesis ornithine decarboxylase (ODC), which catalyzes the rate-limiting step in the biosynthesis of the polyamines, was immunohistochemically localized in the ovaries from rat and hamster during pro-oestrus. At dioestrus, only a few immunoreactive cells were found in the ovaries. During the evening of pro-oestrus, on the other hand, numerous immunoreactive cells were observed in the ovaries. These cells were confined to the internal thecal layer of Graafian as well as smaller follicles and to the interstitial tissue of the ovary. The granulosa cells appeared to be devoid of immunoreactive ODC. The hamster ovary, which during this time exhibited considerably higher levels of ODC activity than the ovaries from the rat, did accordingly contain more immunoreactive cells than the rat ovary.

Risk Factors of HHV6 Reactivation and Relationship Between Syndrome of Inappropriate Antidiuretic Hormone Secretion After Stem Cell Transplantation in Pediatric Patients

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4580-4580
Author(s):  
Ryoji Kobayashi ◽  
Naohisa Toriumi ◽  
Makoto Yoshida ◽  
Akihiro Iguchi ◽  
Takeo Sarashina ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Antidiuretic Hormone ◽  
Cell Transplantation ◽  
Pediatric Patients ◽  
Hormone Secretion ◽  
The Other ◽  
Inappropriate Antidiuretic Hormone Secretion ◽  
Antidiuretic Hormone Secretion ◽  
Other Hand

Abstract Abstract 4580 Many reports were seen about reactivation of human herpes virus 6 (HHV6) after stem cell transplantation (SCT) in adult patients, and this reactivation sometimes induce severe condition of patients. However, few reports were seen about pediatric patients. Therefore, we examined HHV 6 reactivation after stem cell transplantation in patients with children, retrospectively. The cases were 80 patients, 48 male, 32 female, and the median age was 6 years old (range 0–20 years old). Transplantations were 23 related bone marrow transplantations (BMT) or peripheral blood stem cell transplantations (PBSCT), 18 unrelated BMT, one related cord blood transplantation (CBT), 31 unrelated CBT, and seven autologous BMT or PBSCT. We analyzed HHV6 DNA samples of serum with these patients before SCT, 20 days and 40 days after SCT using PCR method. In addition, we analyzed relationship between HHV6 reactivation and syndrome of inappropriate antidiuretic hormone secretion (SIADH). In samples of 20 days after SCT, 35.0% of samples were positive for HHV6 DNA. On the other hand, 2.5% and 5.0% were positive before SCT and 40 days after SCT, respectively. From 24 out of 28 samples, over 10E3 of HHV6 DNA were detected in positive samples. Factors associated with HHV6 reactivation were CBT, unrelated donor, malignant diseases, use of total body irradiation as conditioning, cyclosporine and methyl prednisolone as GVHD prophylaxis, acute GVHD (>grade 2), chronic GVHD and use of steroid using univariate analysis. Moreover, CBT was an only risk factor of HHV6 reactivation using multivariate analysis. In 14 patients with SIADH, 78.6% of patients had HHV6 reactivation. On the other hand, 25.8% of patients had HHV6 reactivation in 66 patients without SIADH. This result was statistically significant (p<0.001). From this analysis, we can understand HHV6 reactivation was seen in many patients with children. In addition, we thought about the possibility of SIADH is one symptom of the encephalopathy by the HHV6 reactivation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Prenatal Influence of an Androgen Agonist and Antagonist on the Differentiation of the Ovine Sexually Dimorphic Nucleus in Male and Female Lamb Fetuses

Endocrinology ◽  
2014 ◽  
Vol 155 (12) ◽  
pp. 5000-5010 ◽  
Author(s):  
Charles E. Roselli ◽  
Radhika C. Reddy ◽  
Charles T. Estill ◽  
Melissa Scheldrup ◽  
Mary Meaker ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Receptor Antagonist ◽  
Critical Period ◽  
Hormone Secretion ◽  
Feedback Mechanism ◽  
Sexually Dimorphic ◽  
Negative Feedback Mechanism ◽  
Androgen Receptor Antagonist ◽  
Reproductive Axis ◽  
Sexually Dimorphic Nucleus

The ovine sexually dimorphic nucleus (oSDN) is 2 times larger in rams than in ewes. Sexual differentiation of the oSDN is produced by testosterone exposure during the critical period occurring between gestational day (GD)60 and GD90 (term, 147 d). We tested the hypothesis that testosterone acts through the androgen receptor to control development of the male-typical oSDN. In experiment 1, pregnant ewes received injections of vehicle, androgen receptor antagonist flutamide, or nonaromatizable androgen dihydrotestosterone (DHT) propionate during the critical period. Fetuses were delivered at GD135. Both antagonist and agonist treatments significantly reduced mean oSDN volume in males but had no effects in females. Experiment 2, we analyzed the effect of treatments on the fetal hypothalamic-pituitary-gonadal axis to determine whether compensatory changes in hormone secretion occurred that could explain the effect of DHT. Pregnant ewes were injected with vehicle, flutamide, or DHT propionate from GD60 to GD84, and fetuses were delivered on GD85. Flutamide significantly increased LH and testosterone in males, whereas DHT significantly decreased both hormones. In females, LH was unaffected by flutamide but significantly reduced by DHT exposure. DHT significantly decreased pituitary gonadotropin and hypothalamic kisspeptin mRNA expression in males and females. These results suggest that androgen receptor mediates the effect of testosterone on oSDN masculinization, because this process was blocked by the androgen receptor antagonist flutamide in eugonadal males. In contrast, the reduction of oSDN volume observed after DHT exposure appears to be mediated by a negative feedback mechanism exerted on the hypothalamus to reduce LH and testosterone secretion. The reduced androgen exposure most likely accounted for the decreased oSDN volume. We conclude that, during the critical period, the male reproductive axis in long gestation species, such as sheep, is sufficiently developed to react to perturbations in serum androgens and mitigate disruptions in brain masculinization.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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