LUTEOLYTIC EFFECTS OF OESTRADIOL AFTER HYPOPHYSECTOMY OR PITUITARY STALK SECTION IN CYCLING SHEEP

1973 ◽  
Vol 73 (4) ◽  
pp. 635-642 ◽  
Author(s):  
R. Denamur ◽  
G. Kann
Keyword(s):  
Pituitary Gland ◽  
Life Span ◽  
Corpus Luteum ◽  
Direct Action ◽  
The Other ◽  
Pituitary Stalk ◽  
Relative Importance ◽  
Luteal Regression ◽  
Other Hand ◽  
Oestradiol Benzoate

ABSTRACT Experiments were carried out with a view to determining the relative importance of the pituitary gland and the uterus for the luteolytic action of oestradiol in the cycling ewe. The influence of the pituitary was modified by stalk section or hypophysectomy and that of the uterus by hysterectomy. Oestradiol (0.5 mg twice daily) caused an increase in ghe life-span of the corpus luteum (CL) if treatment began on day 3 of the cycle, and a decrease when injections commenced on days 9 or 11. Pituitary stalk sections performed on days 3 or 11 caused little change in CL weight on day 14. However, in either case, oestradiol administration from day 11 resulted in a large fall in CL weight, indicating that intact pituitary connections to the hypothalamus were not essential for the luteolytic action of oestradiol. Luteal regression following hypophysectomy on day 11 was accelerated by oestradiol benzoate injected from day 11. On the other hand, hysterectomy on day 11 always resulted in maintenance of the CL to day 20, whether or not stalk section or oestradiol administration had taken place. This indicated that the presence of the uterus was essential for the luteolytic effects of oestradiol. These experiments show that the luteolytic properties of oestradiol reflect mainly a direct action of this hormone on the uterus.

CHANGES IN PLASMA LEVELS OF PROLACTIN AND LH INDUCED BY LUTEOLYTIC OR LUTEOTROPHIC TREATMENT IN INTACT CYCLING SHEEP AFTER SECTION OF THE PITUITARY STALK

1973 ◽  
Vol 73 (4) ◽  
pp. 625-634 ◽  
Author(s):  
G. Kann ◽  
R. Denamur
Keyword(s):  
Pituitary Gland ◽  
Plasma Levels ◽  
Limit Of Detection ◽  
Oestrous Cycle ◽  
The Other ◽  
Pituitary Stalk ◽  
Similar Treatment ◽  
Luteal Regression ◽  
Gonadotrophin Secretion ◽  
Major Increase

ABSTRACT Oestradiol has been shown to cause either premature luteal regression or prolonged luteal maintenance depending on whether it is administered early or late in the oestrous cycle. Although these effects are not observable in the absence of the uterus, it was considered desirable to examine the possibility that the pituitary gland as well as the uterus may be involved in this phenomenon. Accordingly, plasma LH and prolactin concentrations were studied in sheep treated with oestradiol from day 3 (luteotrophic action) or day 11 (luteolytic action) with and without pituitary stalk section. Plasma LH fell below the limit of detection (0.3 ng/ml) in the plasma of sheep after pituitary stalk section, whether or not oestradiol had been administered. In the intact ewe, oestradiol given from day 3 resulted in luteal maintenance associated with a significant increase in the secretion of plasma LH and prolactin. However, similar treatment in the stalk sectioned ewe also resulted in luteal maintenance without any major increase in gonadotrophin secretion. On the other hand, when oestradiol was given from day 11, there was no evidence either from the intact or the stalk sectioned sheep that the pituitary contributed to the luteolytic action of oestradiol may possibly have a pituitary component, the luteolytic action is probably mediated solely by the oestrogenic action on the uterus.

The Relative Importance of the Different Relationship Platforms (Physical and Virtual) in the Consumer Experience of Luxury Brands

2016 ◽  
pp. 133-154
Author(s):  
Paola Peretti ◽  
Mohanbir Sawhney
Keyword(s):  
The Other ◽  
Relative Importance ◽  
Luxury Brands ◽  
Consumer Experience ◽  
Physical Relationship ◽  
Luxury Brand ◽  
Luxury Branding ◽  
Other Hand ◽  
Consumer Experiences ◽  
The One

Managing luxury brands nowadays is complex (Wiedmann & Hennigs, 2012). On the one hand, luxury brands built their development through a strategic use of physical relationship platforms, making the customer experience inside points of sale an indispensable element for their growth. On the other hand, over the past 10 years, we have seen leading global luxury brands embrace virtual platforms in various ways to re-imagining consumer experiences. Blending these new elements can present challenges. The purpose of this chapter is to understand the relative importance of the different relationship platforms (physical and virtual) in the consumer experience of luxury brands and how has it changed. Results are able on the one hand to expand the theory of luxury branding and on the other hand to highlight some key implications for luxury brand managers.

scholarly journals Century Bonds: Debt Or Equity Securities?

2011 ◽  
Vol 19 (3) ◽  
Author(s):  
Kam C. Chan ◽  
P.V. Viswanath ◽  
Annie Wong
Keyword(s):  
Systematic Risk ◽  
Tax Avoidance ◽  
The Other ◽  
Formal Structure ◽  
Relative Importance ◽  
Firm Characteristics ◽  
Font Size ◽  
Other Hand ◽  
Equity Securities

<p class="MsoBlockText" style="margin: 0in 0.5in 0pt;"><span style="font-style: normal; mso-bidi-font-style: italic;"><span style="font-size: x-small;"><span style="font-family: Times New Roman;">In this study, we examine the characteristics of firms that have issued century bonds and the debt-versus-equity classification of these bonds.<span style="mso-spacerun: yes;">&nbsp; </span>Although it is commonly assumed that such bonds are issued for tax-avoidance purpose, an examination of firm characteristics suggests that firms have non-tax related motives in issuing century bonds.<span style="mso-spacerun: yes;">&nbsp; </span>The formal structure of century bonds also suggests that century bonds are similar to debt.<span style="mso-spacerun: yes;">&nbsp; </span>On the other hand, our analysis of the systematic risk of issuing firm's equity shows that century bonds are more similar to equity than to debt.<span style="mso-spacerun: yes;">&nbsp; </span>Thus, ultimately, the relative importance of these three factors will have to determine whether they are to be considered debt or equity.<span style="mso-spacerun: yes;">&nbsp; </span></span></span></span></p>

Plasma prolactin in the rat during suckling without prior separation from pups

1985 ◽  
Vol 108 (4) ◽  
pp. 468-474 ◽  
Author(s):  
John A. M. Mattheij ◽  
Hans J. M. Swarts ◽  
Simone van Mourik
Keyword(s):  
Pituitary Gland ◽  
The Other ◽  
Plasma Prolactin ◽  
Low Level ◽  
Litter Removal ◽  
Other Hand ◽  
Plasma Prl ◽  
Secretory Capacity

Abstract. The relation between suckling and plasma prolactin (Prl) was studied in the rat, without prior separation of the dam from its pups. When the pups were replaced by a hungry foster litter, upon renewed suckling plasma Prl showed episodic increases and decreases in individual rats. When, subsequent to litter removal, similar rats were injected with perphenazine, a significant increase of plasma Prl was observed. This indicates that a decline of plasma Prl during suckling was not caused by exhaustion of Prl stores in the pituitary. In 22 individual rats blood was sampled every other minute while observations were made on nursing behaviour of the dams. During apparent suckling, increases as well as decreases of plasma Prl occurred. However, in most cases suckling did not affect plasma Prl, i.e. it remained stable at a high or a relatively low level. On the other hand, a considerable rise of plasma Prl was frequently observed when a dam was away from the nest. The data indicate that in the physiological situation Prl secretion from the pituitary is not directly related suckling activity, though episodes of suckling are essential to maintain a high Prl secretory capacity of the pituitary gland.

Life-Span Determinants of Work in Retirement Years

1988 ◽  
Vol 27 (2) ◽  
pp. 125-140 ◽  
Author(s):  
Nancy Morrow-Howell ◽  
Joel Leon
Keyword(s):  
Life Span ◽  
Path Analysis ◽  
Labor Force ◽  
Structural Characteristics ◽  
The Other ◽  
Lower Income ◽  
Work Effort ◽  
Other Hand ◽  
Successful Employment ◽  
Work Histories

This article presents the results of a path analysis to clarify the life-span determinants of work effort in postretirement years. It was found that personal and structural characteristics are different between a group of retirees who did not work in the three years after retirement and those that worked more than 300 hours annually. Those that participated in the labor force after retirement experienced more successful employment histories before retirement. On the other hand, people with more marginal work histories were less likely to sustain work efforts after retirement, despite lower income.

The effect of oestradiol benzoate (ODB) or a synthetic gonadotropin releasing hormone (GnRH) used at the start of a progesterone treatment on onset and synchrony of oestrus in cattle

2001 ◽  
Vol 26 (2) ◽  
pp. 475-478
Author(s):  
E.A. Lane ◽  
E.J. Austin ◽  
M.A. Crowe ◽  
J.F. Roche
Keyword(s):  
Treatment Group ◽  
Life Span ◽  
Corpus Luteum ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Oestrous Cycle ◽  
Beef Heifers ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate ◽  
Vaginal Device

AbstractFixed time insemination requires both the functional life span of the corpus luteum to be regulated and follicle wave status to be synchronised in all animals, irrespective of the stage of oestrous cycle or follicle wave. The objective of this experiment was to compare the oestrous response in heifers given either GnRH or ODB at the start of a progesterone treatment. Treatments were initiated at emergence or dominance of the first follicle wave (days 2 and 5 of the oestrous cycle, respectively) or at emergence or dominance of the second follicle wave (days 10 and 13, respectively). The second objective was to compare the oestrous response in heifers given a luteolytic agent one day before the end of a progesterone treatment of 8 days duration with ODB at the start of treatment compared with a progesterone treatment of 10 days duration with ODB at the start of treatment and without using a luteolytic agent. Charolais cross-bred beef heifers (n=134) were randomly assigned to one of 3 treatments; 0.75 mg ODB given at insertion of a progesterone releasing intra-vaginal device (PRID) treatment of 10 days duration (10dE2), 0.75 mg ODB at insertion of a PPJD treatment of 8 days duration with 15mg luprostiol given one day before PRID removal (8dE2) or 250 fig GnRH at insertion of a PRID treatment of 8 days duration with 15 mg luprostiol given one day before PRID removal (8dGnRH), initiated on days 2, 5, 10 or 13 of the oestrous cycle. Oestrous detection was carried out six times daily from 24 hours after PRID removal. The proportion of heifers detected in oestrus was higher (P<0.05) for heifers in the 8dE2 treatment (40/40) compared with heifers in the GnRH treatment (38/42) and tended to be higher (P=0.08) compared with heifers in the 10dE2 treatment (38/41). The day of cycle on which treatment was initiated did not affect (P>0.05) the proportion of heifers that were detected in oestrus. The median onset of oestrus was earlier (P<0.05) for heifers in the 10dE2 treatment group (median 41 h, range 92 h) compared with either the 8dE2 (median 49 h, range 64 h) or 8dGnRH heifers (median 49 h, range 92 h). The variation in onset of oestrus tended to be decreased (P=0.075) in 8dE2 heifers compared with the 10dE2 heifers but was not different (P>0.05) to heifers in the 8dGnRH treatment group. In conclusion, 0.75 mg ODB given at insertion of a progesterone treatment of 8 days duration with 15 mg luprostiol given one day before progesterone removal increased the proportion of heifers detected in oestrus compared with heifers given 250 μg GnRH at the start of treatment. There was no difference in the efficacy of ODB or GnRH given at insertion of a progesterone treatment of 8 days duration to synchronise oestrus in beef heifers. The use of a luteolytic agent given one day before removal of a progesterone treatment of 8 days duration was more effective to synchronise oestrus than a progesterone treatment of 10 days duration without the use of a luteolytic agent.

SPERM DISTRIBUTION IN FEMALE RABBITS: THE EFFECT OF OVARIAN STEROIDS

1974 ◽  
Vol 76 (4) ◽  
pp. 765-772 ◽  
Author(s):  
D. B. Morton ◽  
R. J. Fitzpatrick ◽  
T. D. Glover
Keyword(s):  
Cervix Uterus ◽  
Hormonal Treatment ◽  
The Other ◽  
Sperm Transport ◽  
Ovarian Steroids ◽  
Other Hand ◽  
Oestradiol Benzoate

ABSTRACT Oestradiol benzoate, progesterone and 20α-hydroxy-4-pregnen-3-one (20α-OH) were injected into ovariectomized rabbits and after either 4 or 5 days the rabbits were inseminated with a standardized inseminate, killed at 2 and 10 h after insemination and the number of spermatozoa in the vagina, cervix, uterus and oviducts was evaluated. The oestrogen increased the number of spermatozoa recovered from the cervix, uterus and oviduct compared with the control ovariectomized group receiving no hormonal treatment. The progestagens, on the other hand, tended to inhibit sperm transport through the cervix depending on the amount given. Injection of both oestrogen and progesterone simultaneously, illustrated their antagonistic actions. The effect of circulating progestagens on sperm transport during oestrus and pseudopregnancy is discussed, as well as their effects on the formation of the cervical reservoir.

scholarly journals XIII. On the action of light upon plants, and of plants upon the atmosphere

1836 ◽  
Vol 126 ◽  
pp. 149-175 ◽  
Keyword(s):  
Carbonic Acid ◽  
Direct Action ◽  
The Other ◽  
Chemical Changes ◽  
Specific Stimulus ◽  
Metallic Oxides ◽  
Other Hand ◽  
Vital Functions ◽  
Saline Solutions

The researches of Priestley, Ingenhousz, Senebier, Ellis, and above all of the younger Saussure, have long put us in possession of the leading facts appertaining to the influence of light upon the green parts of plants; and Professor Decandolle has embodied the substance of all that had been ascertained on this subject, up to the year 1831, in his admirable work on Vegetable Physiology. But there appear, by the confession of this latter naturalist, to remain certain subordinate questions respecting this same function, which, though perhaps occasionally touched upon by the above-cited experimentalists and by others, can scarcely be said to have as yet obtained a satisfactory reply. The first of these questions relates to the nature of the influence which, in the cases alluded to, is assignable to light. As this agent often produces chemical changes by its direct action upon inorganic bodies, decomposing saline solutions, discolouring oils, and reducing metallic oxides, so it may be supposed to operate directly upon the air, and to possess the power of decomposing carbonic acid, when this substance is presented to it within the pores of the vegetable tissue. And, on the other hand, as light appears to be a specific stimulus to the vital functions of animals, so it may be imagined to act in a similar manner on those of plants, thus enabling them to secrete from the carbonic acid presented to them the carbon required for their nutrition.

HYPOPHYSECTOMY IN PREGNANT GOATS, AND SECTION OF THE PITUITARY STALK IN PREGNANT GOATS AND SHEEP

1963 ◽  
Vol 28 (1) ◽  
pp. 93-NP ◽  
Author(s):  
A. T. COWIE ◽  
P. M. DANIEL ◽  
MARJORIE M. L. PRICHARD ◽  
J. S. TINDAL
Keyword(s):  
Anterior Lobe ◽  
The Other ◽  
Pituitary Stalk ◽  
Gestation Period ◽  
Other Hand ◽  
Pregnant Sheep

SUMMARY Pregnant goats hypophysectomized between the 38th and 120th days of the gestation period aborted 3–9 days after operation. Pregnant goats subjected to section of the pituitary stalk between the 44th and 129th days of gestation aborted between the 6th and 17th days after operation. On the other hand, section of the pituitary stalk in pregnant sheep between the 42nd and the 90th days of gestation did not interfere with the pregnancy. In both goats and sheep the operation of stalk section included the insertion of a plate to form a barrier between the cut ends of the stalk. The only goats which did not abort were two of the hypophysectomized group in which some anterior lobe tissue, adjacent to the stalk, had not been removed, and one stalk-sectioned goat in which the plate had moved after insertion, allowing the cut ends of the stalk to join up.

scholarly journals Sexual Dimorphic Distribution of Hypothalamic Tachykinin1 Cells and Their Innervations to GnRH Neurons in the Zebrafish

2021 ◽  
Vol 11 ◽  
Author(s):  
Satoshi Ogawa ◽  
Priveena Nair Ramadasan ◽  
Rachel Anthonysamy ◽  
Ishwar S. Parhar
Keyword(s):  
Direct Action ◽  
Brain Regions ◽  
The Other ◽  
Neurokinin A ◽  
Male And Female ◽  
Other Hand ◽  
Neural Processes ◽  
Confocal Images ◽  
Female Zebrafish

Substance P (SP) and neurokinin A (NKA), encoded by TAC1/Tac1 gene are members of the tachykinin family, which exert their neuromodulatory roles in vertebrate reproduction. In mammals, SP and NKA have been shown to regulate gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion via kisspeptin neurons. On the other hand, the role of SP/NKA in the regulation of reproduction in non-mammalian vertebrates is not well known. In the present study, we first localized expression of tac1 mRNA in the brain of male and female zebrafish, Danio rerio. Next, using an antibody against zebrafish tachykinin1 (Tac1), we examined the neural association of SP/NKA neural processes with GnRH3 neurons, and with kisspeptin (kiss2) neurons, in the brains of male and female zebrafish. In situ hybridization showed an apparent male-dominant tac1 expression in the ventral telencephalic area, the anterior and posterior parts of the parvocellular preoptic nucleus, and the suprachiasmatic nucleus. On the other hand, there was female-dominant tac1 expression in the ventral periventricular hypothalamus. Confocal images of double-labeled zebrafish Tac1 and GnRH3 showed associations between Tac1-immunoreactive processes and GnRH3 neurons in the ventral telencephalic area. In contrast, there was no apparent proximity of Tac1 processes to kiss2 mRNA-expressing neurons in the hypothalamus. Lastly, to elucidate possible direct action of SP/NKA on GnRH3 or Kiss2 neurons, expression of SP/NKA receptor, tacr1a mRNA was examined in regions containing GnRH3 or Kiss2 neurons by in situ hybridization. Expression of tacr1a mRNA was seen in several brain regions including the olfactory bulb, preoptic area and hypothalamus, where GnRH3 and Kiss2 cells are present. These results suggest that unlike in mammals, Tac1 may be involved in male reproductive functions via direct action on GnRH3 neurons but independent of kisspeptin in the zebrafish.

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