Independence of ovarian progesterone secretion rate from arterial progesterone concentrations in the pregnant rat

1982 ◽  
Vol 94 (1) ◽  
pp. 61-67 ◽  
Author(s):  
B. J. Waddell ◽  
N. W. Bruce ◽  
J. K. Olynyk
Keyword(s):  
Secretion Rate ◽  
Separate Experiment ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
Fivefold Increase ◽  
The Face ◽  
Arterial Plasma ◽  
The Stability

We have sought to determine whether the rate of ovarian progesterone secretion in pregnant rats is inversely related to the arterial plasma progesterone concentrations. For this purpose, rates of ovarian progesterone secretion were measured on day 16 of pregnancy in seven progesterone-treated and eight untreated rats. Treated rats received once-daily s.c. injections of 63·6 μmol progesterone in peanut oil on days 13 to 16. In a separate experiment, this treatment was found to produce a relatively stable fivefold increase in plasma progesterone concentrations. The rate of ovarian blood flow was increased in treated animals (mean ± s.e.m.; treated, 0·63± 0·08 ml/min; untreated, 0·43± 0·08 ml/min) but the progesterone secretion rate was unchanged (treated, 1·13 ± 0·20 μmol/day per ovary; untreated, 1·05 ± 0·15 μmol/day per ovary). The stability of the progesterone secretion rate in the face of a fivefold increase in plasma progesterone concentration implies a lack of negative feedback from progesterone in plasma in the regulation of ovarian progesterone secretion.

The acute effect of placentectomy and hysterectomy on peripheral plasma progesterone levels and ovarian progesterone secretion in the pregnant rat

1983 ◽  
Vol 98 (1) ◽  
pp. 71-77 ◽  
Author(s):  
J. K. Olynyk ◽  
N. W. Bruce ◽  
B. J. Waddell
Keyword(s):  
Acute Effect ◽  
Initial Experiment ◽  
Direct Role ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Progesterone Secretion ◽  
And Control

The role of placental luteotrophins in modulating plasma progesterone concentrations and ovarian progesterone secretion was examined in 16-day pregnant rats. In an initial experiment rats were placentectomized and their plasma progesterone concentrations monitored for 24 h; the rats were conscious within 30 min of placentectomy. Relative to control values, progesterone concentrations fell significantly within 0·5 h. A venous outflow technique was then used to monitor rates of progesterone secretion from ovaries of hysterectomized and control rats maintained under anaesthesia. Hysterectomy had no apparent effect on either progesterone secretion or plasma progesterone concentrations for at least 2 h. A final experiment was carried out to compare the effects of hysterectomy on plasma progesterone concentrations in conscious rats with those of placentectomized rats of the first experiment. Progesterone concentrations did not change significantly in hysterectomized rats for 4 h but fell to very low values by 24 h. These results suggest that placental luteotrophins do not have an acute, direct role in the control of plasma progesterone levels but are needed to maintain progesterone secretion in the longer term and possibly inhibit uterine luteolysin release.

PLASMA PROLACTIN AND PROGESTERONE RESPONSES TO MATING ARE ALTERED IN AGED RATS

1981 ◽  
Vol 90 (2) ◽  
pp. 179-191 ◽  
Author(s):  
S. HENDRICKS ◽  
C. A. BLAKE
Keyword(s):  
Plasma Concentrations ◽  
External Jugular Vein ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Aged Rats ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
The One ◽  
The Right

The effects of varying amounts of copulatory stimulation on patterns of plasma concentrations of prolactin and progesterone were evaluated in 3- and 12-month-old female rats. The 12-month-old group included rats which still exhibited oestrous cycles and rats in persistent vaginal oestrus (PVO). The extent of copulatory stimulation was defined by the number of intromissions received during mating: ≤5,15 or > 50. Blood samples were drawn over the 8 days after mating through a cannula inserted into the right external jugular vein. Plasma from the samples was assayed for prolactin and progesterone. In aged but still cyclic rats, pregnancy rates were positively correlated with the number of intromissions received during mating. Only one rat in PVO became pregnant. All animals which became pregnant and rats in PVO which, after mating, exhibited a disruption of the pattern of PVO, showed the nocturnal surge of plasma prolactin characteristic of pregnant and pseudopregnant rats. While these surges persisted until day 8 after mating in pregnant animals, they were absent by this time in the rats in PVO. Prolactin surges were present in some but not all of the aged rats which did not become pregnant. Progesterone concentrations were raised in all pregnant animals except the one pregnant rat in PVO and, while not related to the number of intromissions, concentrations were higher 8 days after mating in young compared with those in aged pregnant rats. Plasma progesterone was low in rats in PVO regardless of disruption of the pattern of PVO. We have concluded that the failure of limited copulatory stimulation to induce pregnancy in older rats results, at least in part, from its failure to initiate nocturnal prolactin surges. Nevertheless, our data suggest that matings which are not experimentally limited should provide ample stimulation to establish such surges. Although reduced plasma concentrations of prolactin and progesterone at pro-oestrus and reduced plasma progesterone through part of gestation may contribute to decreasing fertility in aged rats, other unidentified factors appear to be involved in mediating the capacity of extensive copulatory stimulation to induce pregnancy in these animals.

EFFECT OF LUTEINIZING HORMONE ANTISERUM ON PROGESTERONE AND 20α-DIHYDROPROGESTERONE SECRETION IN THE PREGNANT RAT

1972 ◽  
Vol 52 (3) ◽  
pp. 413-418 ◽  
Author(s):  
N. R. MOUDGAL ◽  
H. R. BEHRMAN ◽  
R. O. GREEP
Keyword(s):  
Luteinizing Hormone ◽  
Cholesteryl Ester ◽  
Corpus Luteum ◽  
Free Cholesterol ◽  
Single Injection ◽  
Cholesterol Content ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Progesterone Secretion ◽  
Cholesteryl Ester Content

SUMMARY The effect of a single injection of luteinizing hormone (LH) antiserum on ovarian progesterone and 20α-dihydroprogesterone in day-8 and day-15 pregnant rats was studied. Within 24 h of an injection of LH antiserum, progesterone secretion was reduced by 80% in day-8 and by 25% in day-15 pregnant rats. The 20α-dihydroprogesterone levels after antiserum treatment were markedly increased in rats which were 8 days pregnant but reduced in rats which were 15 days pregnant. The free cholesterol content of the ovary did not change after antiserum injection but the cholesteryl ester content markedly increased. It is thus apparent that neutralization of endogenous LH resulted in a significant reduction in the progesterone secretion of the corpus luteum of the pregnant rat. The significance of these results is discussed.

Potentiation by prolactin of the luteotrophic effect of oestradiol in the pregnant rat

1982 ◽  
Vol 101 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Richard G. Rodway ◽  
David R. Garris
Keyword(s):  
Sampling Period ◽  
Daily Treatment ◽  
Serum Prolactin ◽  
Renal Capsule ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Luteal Function ◽  
Progesterone Secretion

Abstract. The luteotrophic effects of elevated prolactin levels with or without concomitant oestradiol treatment were investigated in the pregnant rat after hysterectomy or hysterectomy plus hypophysectomy. On day 2 of pregnancy, rats were given a single pituitary transplant beneath the renal capsule and were subsequently hysterectomised on day 12. This treatment delayed the next ovulation (as judged by vaginal di-oestrus length) compared to sham-transplanted controls, but did not prevent the fall in serum progesterone concentrations (i.e. luteolysis) resulting from hysterectomy. The administration of 1 or 2 pituitary homo-transplants on day 12 at the time of hysterectomy again prolonged the di-oestrus length but did not prevent subsequent luteolysis. However, daily treatment with 100 μg of oestradiol given to rats which received 2 pituitary transplants on day 2 and which were then hysterectomised on day 12, did result in a maintenance of serum progesterone levels compared to those of oil-treated controls. In a separate study, pregnant rats were hysterectomised and hypophysectomised on day 12. Administration of either 1 or 2 pituitary transplants failed to maintain luteal function. However, concomitant daily treatment with 100 μg of oestradiol from day 12 onward prevented luteolysis and re-instated the day 12–16 rise in serum progesterone common to the intact pregnant rat. Progesterone levels then declined slowly until the end of the sampling period (day 23). Serum prolactin concentrations rose steadily for the first 10 days after insertion of pituitary transplants on day 12 of pregnancy. These data indicate that prolactin and oestradiol can act synergistically to stimulate progesterone secretion from the rat corpus luteum but only in the absence of the in situ pituitary; the effect is not seen unless hypophysectomy has been performed.

scholarly journals OBSERVATIONS ON THE PREGNANT RAT INJECTED WITH NEPHROTOXIC RABBIT ANTI-RAT PLACENTA SERUM AND DESOXYCORTICOSTERONE ACETATE

1949 ◽  
Vol 89 (3) ◽  
pp. 287-293 ◽  
Author(s):  
Emily N. Loeb ◽  
Abbie I. Knowlton ◽  
Herbert C. Stoerk ◽  
Beatrice C. Seegal
Keyword(s):  
Blood Pressure ◽  
Renal Damage ◽  
Concomitant Administration ◽  
Termination Of Pregnancy ◽  
Daily Administration ◽  
Renal Hypertrophy ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
The Face ◽  
Desoxycorticosterone Acetate

1. Pregnancy enhances the susceptibility of the rat to intercurrent renal damage produced by anti-placenta serum. This is manifested by the development of renal hypertrophy and nephritis in a number of these animals. Both renal hypertrophy and nephritis are consistently intensified by the concomitant administration of DCA. 2. Hypertension develops in both pregnant and non-pregnant rats treated with the anti-placenta serum employed together with the daily administration of DCA. 3. Termination of pregnancy, in the face of continued DCA administration, fails to lower the blood pressure or to arrest the nephritic process.

Em transe-to

2020 ◽  
Vol 2 (1) ◽  
pp. 32-55
Author(s):  
Natalia Christofoletti Barrenha
Keyword(s):  
The Face ◽  
The Stability ◽  
The City

This text seeks to explore the Argentine films Castro (Alejo Moguillansky, 2009) and El asaltante (Pablo Fendrik, 2007) from within the displacement of their characters through the city. This transit configures the organising element of the plots, determining the direction and rhythm of events. The escape motto will structure the film analyses, which are also twinned by the sensory apprehension that comes from the spaces they travel through. The notion of escape, as explored by Esteban Dipaola in Argentine cinema of the 1990s, continues to throb in mid-to-late 2000s production, and in these films represents the means by which the protagonists deploy critical attitudes—sometimes radical and explosive, sometimes silent—in the face of fixed notions, suggesting some scepticism about the “stability” and “order” that they (dis)encounter in normality. RESUMEN Este texto busca explorar los largometrajes argentinos Castro (Alejo Moguillansky, 2009) y El asaltante (Pablo Fendrik, 2007) a partir del desplazamiento de sus personajes por la ciudad. El transitar se configura como elemento organizador de las tramas, determinando la dirección y el ritmo de los acontecimientos. El tema de la fuga irá estructurando los análisis de las películas, las cuales también están relacionadas por la aprehensión sensorial que hacen de los espacios que recorren. La noción de fuga, tal y como fue explorada por Esteban Dipaola en el cine argentino de los años 90, continúa vigente en la producción de mediados/fines de la primera década del siglo XXI, y en estas películas es el recurso por medio del cual los protagonistas despliegan actitudes críticas – a veces radicales y explosivas, y a veces silenciosas – frente a nociones convencionales, lo cual hace pensar que existe un cierto escepticismo con relación a la “estabilidad” y al “orden” que ellos (des)encuentran en la normalidad. RESUMO Este texto busca explorar os longas-metragens argentinos Castro (Alejo Moguillansky, 2009) e El asaltante (Pablo Fendrik, 2007) a partir do deslocamento de seus personagens pela cidade. O transitar configura-se como elemento organizador das tramas, determinando a direção e o ritmo dos acontecimentos. O mote da fuga estruturará as análises dos filmes, os quais também se irmanam pela apreensão sensorial que fazem dos espaços que percorrem. A noção de fuga, conforme explorada por Esteban Dipaola no cinema argentino da década de 1990, continua a pulsar na produção de meados/fins dos anos 2000, e é, nestes filmes, o recurso através do qual os protagonistas desdobram atitudes críticas – às vezes radicais e explosivas, às vezes silenciosas – diante de noções fixas, sugerindo certo ceticismo em relação à “estabilidade” e à “ordem” que eles (des)encontram na normalidade.

PROGESTERONE IN THE HUMAN PERIPHERAL BLOOD IN THE PREOVULATORY PERIOD OF THE MENSTRUAL CYCLE

1967 ◽  
Vol 55 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Benno Runnebaum ◽  
Josef Zander
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
Graafian Follicle ◽  
The Mean ◽  
Mean Concentration

ABSTRACT Progesterone was determined and identified in human peripheral blood during the preovulatory period of the menstrual cycle, by combined isotope derivative and recrystallization analysis. The mean concentration of progesterone in 1.095 ml of plasma obtained 9 days before ovulation was 0.084 μg/100 ml. However, the mean concentration of progesterone in 1.122 ml of plasma obtained 4 days before ovulation was 0.279 μg/100 ml. These data demonstrate a source of progesterone secretion other than the corpus luteum. The higher plasma-progesterone concentration 4 days before ovulation may indicate progesterone secretion of the ripening Graafian follicle of the ovary.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

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