MODIFICATIONS DES CELLULES GONADOTROPES ET DU CONTENU EN FSH DE LA GLANDE PITUITAIRE DANS LES CONDITIONS DE LA PONTE PROVOQUEE CHEZ LA RATTE

1969 ◽  
Vol 62 (4) ◽  
pp. 607-623 ◽  
Author(s):  
J. Roos
Keyword(s):  
Synergistic Action ◽  
The Other ◽  
Female Rats ◽  
List Type ◽  
Β Cells ◽  
Other Hand

ABSTRACT The action exerted by an early mating on the pituitary β and γ cells and on the pituitary FSH content has been studied in 4-day cyclic female rats which were mated at 5–6 p. m. on dioestrus 2 after being injected with oestradiol (10 μg) at 10–11 p.m. on dioestrus 1. The following results were obtained: Oestradiol alone induces, on one hand, a highly significant decrease with respect to control animals of the percentage of the γ cells, on the other hand, an increase of the granular content of the β cells. Ovulation only occurs in 5 % of these oestrogenized rats. After early mating a further diminution of the percentage of the γ cells was observed concomitantly with a strong degranulation of the β cells; this early coitus triggered ovulation in 52 % of the females. The pituitary FSH bioassay evidenced a stockage of FSH in oestrogenized females with respect to control animals and on the contrary a FSH release under the influence of coitus. It was therefore concluded that early ovulation as well as spontaneous ovulation in the rat require the synergistic action of both FSH and LH gonadotrophic hormones.

scholarly journals Predominant androgenic component in the stimulatory effect of dehydroepiandrosterone on bone mineral density in the rat

1998 ◽  
Vol 157 (3) ◽  
pp. 433-442 ◽  
Author(s):  
C Martel ◽  
A Sourla ◽  
G Pelletier ◽  
C Labrie ◽  
M Fournier ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Bone Mineral ◽  
Bone Volume ◽  
The Other ◽  
Female Rats ◽  
Trabecular Bone Volume ◽  
A Value ◽  
Other Hand ◽  
Dhea Treatment ◽  
Trabecular Number

In order to assess the relative roles of the androgenic and/or estrogenic components in the stimulatory effect of dehydroepiandrosterone (DHEA) on bone mineral content (BMC) and density (BMD), ovariectomized (OVX) female rats received DHEA administered alone or in combination with the antiandrogen flutamide (FLU) or the antiestrogen EM-800 for 12 months. We also evaluated, for comparison, the effect of estradiol (E2) and dihydrotestosterone (DHT) constantly released by Silastic implants as well as medroxyprogesterone acetate (MPA) released from poly(lactide-co-glycolide) microspheres. Femoral BMD was decreased by 11% 1 year after OVX, but treatment of OVX animals with DHEA increased BMD to a value 8% above that of intact animals. The administration of FLU reversed by 76% the stimulatory effect of DHEA on femoral BMD and completely prevented the stimulatory effect of DHEA on total body and lumbar spine BMD. Similar results were obtained for BMC. On the other hand, treatment with the antiestrogen EM-800 did not reduce the action of DHEA on BMD or BMC. At the doses used, MPA, E2 and DHT increased femoral BMD, but to a lesser degree than observed with DHEA. Bone histomorphometry measurements were also performed. While DHEA treatment partially reversed the marked inhibitory effect of OVX on the tibial trabecular bone volume, the administration of FLU inhibited by 51% (P < 0.01) the stimulatory effect of DHEA on this parameter. The addition of EM-800 to DHEA, on the other hand, increased trabecular bone volume to a value similar to that of intact controls. DHEA administration markedly increased trabecular number while causing a marked decrease in the intertrabecular area. The above stimulatory effect of DHEA on trabecular number was reversed by 54% (P < 0.01) by the administration of FLU, which also reversed by 29% the decrease in intertrabecular area caused by DHEA administration. On the other hand, the addition of EM-800, while further decreasing the intertrabecular space achieved by DHEA treatment, also led to a further increase in trabecular number to a value not significantly different from that of intact control animals, suggesting an additional effect of EM-800 over that achieved by DHEA. Treatment with DHEA caused a 4-fold stimulation of serum alkaline phosphatase, a marker of bone formation, while the urinary excretion of hydroxyproline, a marker of bone resorption, was decreased by DHEA treatment. Treatment with DHEA and DHEA + EM-800 decreased serum cholesterol levels by 22 and 65% respectively, while the other treatments had no significant effect on this parameter. The present data indicate that the potent stimulatory effect of DHEA on bone in the rat is mainly due to the local formation of androgens in bone cells and their intracrine action in osteoblasts.

scholarly journals Application of the Electrical (Geophysical) Method for the Identification of the Sealed Bevel in the Coastal Region of Walidia Province of el Jadida – Morocco

2018 ◽  
Vol 37 ◽  
pp. 05003
Author(s):  
H. Elfjiji ◽  
A. Boukdir ◽  
A. Zitouni
Keyword(s):  
Salt Water ◽  
Coastal Region ◽  
Upper Jurassic ◽  
The Other ◽  
List Type ◽  
Mineral Salts ◽  
Marine Invasion ◽  
Roof Structure ◽  
Other Hand ◽  
The One

The Walidia area knows a great development of agricultural, industrial, maritime activities and a very great demographic expansion. This development is accompanied by a growing demand for water. On the other hand, any intense abstraction of fresh water at a coastal aquifer capture field causes a decrease in groundwater flow and a lowering of the piezometric surface. There is therefore a danger of advancing towards the land of the saltwater bevel and salinization of groundwater which is gradually loaded into mineral salts and can reach abnormally high levels. This work deals with the application of geophysics by electrical sounding method to the in-depth study of the freshwater-salt water interface (salted bevel) on the one hand and the study of the lateral and vertical evolution of the geometry of the different aquifers. The principle of the method is, when performing an electrical survey, to research how varies, at a given point on the surface, the resistivity of the subsoil vertically. For this one executes in a same place a succession of measurements, increasing each time the dimensions of the device and thus the depth of investigation which is proportional to them. At this site, we explore a slice of ground increasingly thick and thus highlights the changes in geological constitution along the vertical. The electrical soundings were carried out with the classic Schlumberger device. The interpretation and the exploitation of the data of the electric soundings carried out made it possible to : Follow the evolution of the salted bevel roof, Draw the upstream limit (marine invasion) of salted bevel Hauterivian, on the one hand, and Valanginian and Jurassic on the other hand, Follow the roof structure of Dridrat limestone (Hauterivien) and limestones of Valanginien and Upper Jurassic, Draw the map of the marl roof of Safi (Hauterivian) constituting the impermeable substratum of Dridrat limestones.

The Importance of Mesenchymal Factors in the Differentiation of Chick Epidermis

Development ◽  
1961 ◽  
Vol 9 (3) ◽  
pp. 370-384
Author(s):  
C. B. McLoughlin
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Squamous Epithelium ◽  
The Other ◽  
Β Cells ◽  
Preen Gland ◽  
Other Hand ◽  
Stratified Squamous Epithelium

It is well established that in the developing chick the underlying mesenchyme initiates the appearance of specific epidermal derivatives, e.g. feathers (Sengel, 1956), claws (Cairns & Saunders, 1954), and the preen gland (Gomot, 1958). On the other hand, it is not yet known to what extent the epidermis is independent of mesenchymal intervention for its basic differentiation into a stratified, squamous epithelium. Sobel's (1958) work on the 8-day chick pituitary suggests that the differentiation and multiplication of certain epithelial cells cannot proceed in the absence of mesenchymal elements. She found that the isolated epithelial cells of the hypophysial rudiment survived but were unable to differentiate or multiply; when associated with perichondrial fibroblasts, however, they resumed mitosis and produced typical α and β cells. In the first part of the present investigation, experiments were made to see whether the embryonic epidermis, like the hypophysial epithelium, requires the resence of fibroblasts to enable it to grow and differentiate, or whether it can proliferate, acquire its characteristic squamous structure and keratinize, when isolated and cultivated in the absence of connective tissue.

THE UPTAKE OF 17β-OESTRADIOL IN BREAST TISSUE OF FEMALE RATS

1968 ◽  
Vol 58 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Sten Sander
Keyword(s):  
Skeletal Muscle ◽  
Direct Effect ◽  
Breast Tissue ◽  
The Other ◽  
Female Rats ◽  
Competitive Effect ◽  
Simultaneous Injection ◽  
Other Hand ◽  
Uptake Pattern ◽  
Wet Weight

ABSTRACT The uptake of radioactivity in breast tissue after the injection of tritiated oestradiol in rats has been studied. The breast tissue accumulates more radioactivity per unit wet weight than skeletal muscle and fat, for at least 4 hours. The uptake of radioactivity does not, however, reach the high levels observed in the uterus. On the other hand, the uptake pattern found in the breast tissue corresponds to previous findings in other oestrogen responsive organs. The uptake of radioactivity by breast tissue in castrated rats is higher than in control animals with their ovaries intact. It is also found that simultaneous injection of non-radioactive oestradiol reduces the uptake of radioactivity. These findings may be explained as a competitive effect between non-labelled and labelled oestradiol. The accumulation of oestradiol observed may be consistent with the idea of a direct effect on breast tissue.

scholarly journals 6-Carboxymethyl genistein: a novel selective oestrogen receptor modulator (SERM) with unique, differential effects on the vasculature, bone and uterus

2002 ◽  
Vol 173 (3) ◽  
pp. 415-427 ◽  
Author(s):  
D Somjen ◽  
Y Amir-Zaltsman ◽  
B Gayer ◽  
T Kulik ◽  
E Knoll ◽  
...  
Keyword(s):  
Molecular Modelling ◽  
Oestrogen Receptor ◽  
Specific Activity ◽  
The Other ◽  
Female Rats ◽  
Rat Tissues ◽  
Receptor Modulator ◽  
Other Hand ◽  
Selective Oestrogen Receptor Modulator

The novel genistein (G) derivative, 6-carboxymethyl genistein (CG) was evaluated for its biological properties in comparison with G. Both compounds showed oestrogenic activity in vitro and in vivo. On the other hand G and CG differed in the following parameters: (i) only CG displayed mixed agonist-antagonist activity for oestrogen receptor (ER) alpha in transactivation assays and (ii) only CG was capable of attenuating oestrogen (E(2))-induced proliferation in vascular smooth muscle cells and of inhibiting oestrogen-induced creatine kinase (CK) specific activity in rat tissues. On the other hand only G enhanced the stimulatory effect on CK specific activity in the uterus. In comparison to the selective oestrogen receptor modulator (SERM) raloxifene (RAL), CG showed the same selectivity profile as RAL in blocking the CK response to E(2) in tissues derived from both immature and ovariectomized female rats. Molecular modelling of CG bound to the ligand binding domain (LBD) of ERbeta predicts that the 6-carboxymethyl group of CG almost fits the binding cavity. On the other hand, molecular modelling of CG bound to the LBD of ERalpha suggests that the carboxyl group of CG may perturb the end of Helix 11, eliciting a severe backbone change for Leu 525, and consequently induces a conformational change which could position Helix 12 in an antagonist conformation. This model supports the experimental findings that CG can act as a mixed agonist-antagonist when E(2) is bound to its receptors. Collectively, our findings suggest that CG can be considered a novel SERM with unique effects on the vasculature, bone and uterus.

Breeding

1939 ◽  
Vol 12 (1-2) ◽  
pp. 27-55
Keyword(s):  
The Other ◽  
List Type ◽  
Type Number ◽  
Other Hand ◽  
Average Production ◽  
Eye Colour ◽  
White Leghorns ◽  
The One ◽  
Different Strains

The connection between the Colour of the Eyes, the Mortality, and the Production of White Leghorns. Het Verband tusschen de oogkleur van Witte Leghorns en de Herfte en de productie. Dr. J. B. van der Meulen. Landbouwkundig Tijdschrift, Vol. 50, 1938, p. 868.An investigation, in which 406 White Leghorns of two different strains were used, on the connection between the colour of the eyes of normal healthy pullets at the beginning of the laying period on the one hand and the production and mortality during the pullet year on the other hand, led to the following conclusions:—1.The mortality amongst hens with abnormal colour of the eyes, (brown-grey and/or blue) is considerably higher than that amongst birds with normal orange coloured eyes, and the production of the former is on the average lower than that of the latter.2.Birds with one normal and one abnormal coloured eyes, correspond to birds with normal coloured eyes as far as mortality is concerned, but their average production resembles more than that of birds with two abnormal eyes.3.Not only an abnormal eye colour but also an abnormal shape of the pupil seems to point to higher mortality and the highest mortality is probable amongst birds which have both an abnormal colour, as well as an abnormal shape of the pupil.

The ARLIS International Conference on Art Periodicals

1976 ◽  
Vol 1 (2) ◽  
pp. 4-9
Author(s):  
Anne Dallett
Keyword(s):  
Contemporary Art ◽  
Effective Action ◽  
The Other ◽  
List Type ◽  
Subscription Rate ◽  
International Conference ◽  
Little Magazines ◽  
Other Hand ◽  
To Come

Each of the 120-odd delegates to the International Conference went away with a different impression. Anne Dallet’s report draws on one of these; it will, we hope, refresh readers’ memories of their conference, as well as informing those who could not attend.Certain themes threaded the whole weekend. The significance of the art periodical, especially in recording contemporary art in the context of its times, for that time and for times to come, was continuously reaffirmed; on the other hand, the problems of publishing and acquiring those ‘little’ magazines which can play such an important part in this process, were raised time and time again. But also, some specific proposals won the approval of the conference, and deserve to be noted here whether or not they are capable of achievement. (Some may be more likely to be translated into effective action if the spirit of the conference can be embodied by an international organisation representing art librarians everywhere). These were (1)that a comprehensive bibliography of art periodicals, and union lists of library subscriptions to and holdings of art magazines, should be compiled;(2)that art librarians should bring periodicals in need of reprinting to the notice of publishers;(3)that art librarians should join in persuading magazine publishers to refrain from extracting from libraries a considerably higher subscription rate than that offered to individuals;(4)that a periodicals subscriptions agency is needed, which will specialise in art, and with whom art librarians could confidently place all their orders (including orders for ‘little’ magazines).

Mechanisms of action of testosterone propionate on LH and FSH release by the pituitary gland in cyclic female rats

1980 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
J. Roos ◽  
S. Plas-Roser ◽  
Cl. Aron
Keyword(s):  
Pituitary Gland ◽  
Sharp Increase ◽  
Testosterone Propionate ◽  
Sharp Decrease ◽  
Mechanisms Of Action ◽  
The Other ◽  
Female Rats ◽  
Corpora Lutea ◽  
Other Hand ◽  
Lh Release

Abstract. The aim of this work was to determine whether changes in pituitary responsiveness to LRH could account for the effect of testosterone propionate (TP) on the gonadotrophic function of the pituitary in 4-day cyclic female rats. Doses of 250, 500 and 1000 ng LRH were injected ip on pro-oestrus at 15.30 h in rats either pre-treated with 5 mg TP on dioestrus II at 10.00 h or injected with 30 mg/kg pentobarbital (PB) at 13.00 h. LH release induced within 30 min by LRH was higher in PB than in TP-treated rats. Even by using 250 ng LRH full ovulation was observed on the morning of oestrus in PB-treated rats. On the other hand, only partial ovulation occurred whatever the dose of LRH used in TP-treated rats; a great number of luteinized follicles was shown to be constantly associated with post-ovulatory corpora lutea. While LRH caused a significant FSH release (30 min later) in TP-treated rats, no FSH release could be shown in PB-treated rats. The pituitary FSH content appeared to be decreased and the pituitary LH content remained unchanged while a sharp increase in both blood FSH and LH concentrations occurred following injection of 1000 ng LRH in TP-treated rats. Concomitantly a sharp decrease in the number of pituitary gonadotrophs (AB-PAS+) was observed. A significant decrease in the number of the small roundshaped PAS positive cells was also observed. The mechanisms whereby TP influences the function of the pituitary-ovarian axis are discussed in the light of these results.

scholarly journals Effects of the loss of estrogen on the heart’s hypertrophic response to chronic left ventricle volume overload in rats

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7924 ◽  
Author(s):  
Elisabeth Walsh-Wilkinson ◽  
Catherine Beaumont ◽  
Marie-Claude Drolet ◽  
Ève-Marie Roy ◽  
Charlie Le Houillier ◽  
...  
Keyword(s):  
Gene Expression ◽  
Left Ventricle ◽  
Natriuretic Peptide ◽  
Systolic Function ◽  
Volume Overload ◽  
The Other ◽  
Female Rats ◽  
Hypertrophic Response ◽  
Other Hand ◽  
Ovx Rats

Aortic valve regurgitation (AR) can result in heart failure from chronic overloading of the left ventricle (LV). Little is known of the role of estrogens in the LV responses to this condition. The aim of the study was to compare LV remodeling in female rats with severe AR in absence of estrogens by ovariectomy (Ovx). In a first study, we investigated over 6 months the development of hypertrophy in four groups of female Wistar rats: AR or sham-operated (sham) and Ovx or not. Ovx reduced normal heart growth. As expected, volume overload (VO) from AR resulted in significant LV dilation (42% and 32% increase LV end-diastolic diameter in intact and Ovx groups vs. their respective sham group; p < 0.0001). LV weight was also significantly and similarly increased in both AR groups (non-Ovx and Ovx). Increase in stroke volume or cardiac output and loss of systolic function were similar between AR intact and AR Ovx groups compared to sham. We then investigated what were the effects of 17beta-estradiol (E2; 0.03 mg/kg/day) treatment on the parameters studied in Ovx rats. Ovx reduced uterus weight by 85% and E2 treatment restored up to 65% of the normal weight. E2 also helped normalize heart size to normal values. On the other hand, it did not influence the extent of the hypertrophic response to AR. In fact, E2 treatment further reduced LV hypertrophy in AR Ovx rats (41% over Sham Ovx + E2). Systolic and diastolic functions parameters in AR Ovx + E2 were similar to intact AR animals. Ovx in sham rats had a significant effect on the LV gene expression of several hypertrophy markers. Atrial natriuretic peptide (Nppa) gene expression was reduced by Ovx in sham-operated females whereas brain natriuretic peptide (Nppb) expression was increased. Alpha (Myh6) and beta (Myh7) myosin heavy chain genes were also significantly modulated by Ovx in sham females. In AR rats, LV expression of both Nppa and Nppb genes were increased as expected. Ovx further increased it of AR rats for Nppa and did the opposite for Nppb. Interestingly, AR in Ovx rats had only minimal effects on Myh6 and Myh7 genes whereas they were modulated as expected for intact AR animals. In summary, loss of estrogens by Ovx in AR rats was not accompanied by a worsening of hypertrophy or cardiac function. Normal cardiac growth was reduced by Ovx in sham females but not the hypertrophic response to AR. On the other hand, Ovx had important effects on LV gene expression both in sham and AR female rats.

scholarly journals Modals and negation: A semantic explanation of the modal suppletion strategy in Chinese

2015 ◽  
Vol 4 (2) ◽  
pp. 163-193 ◽  
Author(s):  
Carlotta Sparvoli
Keyword(s):  
The Other ◽  
List Type ◽  
Semantic Property ◽  
Semantic Account ◽  
Other Hand ◽  
The Subject ◽  
Epistemic Modalities ◽  
Source Orientation ◽  
Standard Chinese ◽  
Negative Form

AbstractThis paper aims at providing a semantic account of the mechanism informing the use of negative modals in standard Chinese. Based on the notion of modal suppletion and negation placement strategies (de Haan 1997), it will be shown that: (i)in the negative form each modal takes on its prominent value;(ii)this prominent modal value displays the normative source orientation (Hsieh 2005), where the Situation-oriented normative source can include the Speaker-oriented normative source and, in particular cases in the domain of Possibility, also the Subject-oriented one;(iii)a negative modal admits different modal meanings only if there is no pragmatic conflict between them, as in the case of epistemic and non-epistemic modalities.Moreover, I will show that in non-epistemic modalities the suppletion mechanism is related to the need for normative disambiguation and is characterized by pragmatic exclusion and semantic inclusion (respectively in the Necessity and Possibility domains). In the epistemic area, on the other hand, the mandatory suppletion of the Speaker-oriented adverbs fulfills the condition of semantic well-formedness of the sentence and, for the other epistemic items, a major role is played by the strategy of negation placement (with the result that the syntactic negation mirrors the semantic property of this modality).

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