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Hypothalamic-pituitary-adrenal axis suppression in asthmatic children on corticosteroidsZollner, Ekkehard Werner Arthur 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Although the effect of inhaled corticosteroids (ICS) on the hypothalamic- pituitary-adrenal
axis (HPA) has been regarded as a “benign physiological response”, a survey published in
2002 suggested that adrenal crisis is more common in asthmatic children on ICS than
previously thought. Relying on clinical features to detect chronic adrenal insufficiency
secondary to corticosteroids may not be wise, as these are non-specific and can therefore
easily be missed. Accurate biochemical assessment of the whole axis to detect subclinical
HPA suppression (HPAS) is thus desirable. A review of the literature indicates that basal
adrenal function tests, including plasma cortisol profiles, do not identify which children can
appropriately respond to stress. There is no evidence to suggest that the degree of the
physiological adjustment of the HPA to ICS and/or nasal steroids (by reducing basal cortisol
production), predicts HPAS. Cortisol profiles should therefore only be used to demonstrate
differences in systemic activity of various ICS and delivery devices. Only two tests,
considered as gold standard adrenal function tests [the insulin tolerance test (ITT) and the
metyrapone test] can assess the integrity of the whole axis. / AFRIKAANSE OPSOMMING: Die outeurs van ´n opname wat in 2002 gepubliseer is stel voor dat ´n bynierkrisis meer
algemeen by asmatiese kinders, wat inhalasie kortikosteroïede ontvang, voorkom as wat
voorheen gedink is. Dit is strydig met die gevestigde opvatting dat die effek van IKS op die
hipotalamiese-hipofise-bynier-as (HHB) ’n “goedaardige fisiologiese reaksie” is. Die kliniese
kenmerke van kroniese bynierontoereikendheid sekondêr tot die gebruik van kortikosteroïede
(KS) is nie-spesifiek en gevolglik onbetroubaar. ´n Akkurate biochemiese toets van
subkliniese HBB onderdrukking (HHBO) sou gevolglik waardevol wees. ´n Literatuur oorsig
toon dat toetse van basale bynierfunksie, insluitend plasma kortisol (K) profiele, nie kinders
uitken wat toepaslik op stres sal reageer nie. Daar is geen bewyse dat die graad van
fisiologiese aanpassing van die HHB, soos aangedui deur laer K-vlakke, na die gebruik van
IKS en/of nasale steroïede (NS), HHBO voorspel nie. Serum K profiele is dus slegs van
waarde om die sistemiese aktiwiteit van verskillende IKS en toedieningsstelsels te ondersoek.
Slegs twee toetse, naamlik die insulien toleransie toets (ITT) en die metyrapone -(MTP)-toets
(wat beide as die goue standaard van bynier funksie beskou word), kan die integriteit van die
hele as meet.
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Effects of steroids and releasing hormones on LH production in cultures of adult turkey pituitary cellsBirrenkott, Glenn, January 1978 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 44-48).
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EFFECTS OF LIGHT DEPRIVATION ON PROLACTIN REGULATION IN THE GOLDEN SYRIAN HAMSTER (PINEAL, ESTROUS CYCLE, BLINDING, MESSENGER-RNA, SYNTHESIS).MASSA, JOHN SAMUEL. January 1986 (has links)
Pineal-mediated depressions in prolactin cell activity after light deprivation were studied in the male and female Golden Syrian hamster. Prolactin cell activity was determined by measuring radioimmunoassayable prolactin, newly synthesized prolactin and prolactin mRNA levels in the pituitary. Serum prolactin was also measured by radioimmunoassay. Use of the recombinant DNA plasmid, pPRL-1, which contains the rat prolactin complimentary DNA sequence, was validated in this dissertation for measuring prolactin mRNA in the hamster. Male hamsters blinded for 11, 21, or 42 days showed significant and progressively greater declines in prolactin mRNA levels which were completely prevented by pinealectomy. The decline seen after 11 days is the earliest depression in prolactin cell activity reported after light deprivation in the hamster. Female hamsters blinded for 28 days, however, showed no such decreases in prolactin cell activity if they continued to display estrous cyclicity. This supports the hypothesis that, unlike the male, there is not a gradual decline in prolactin cell activity after blinding in the female hamster and that loss of estrous cyclicity may precede or possibly accompany declines in prolactin cell activity. After 12 weeks of blinding, females were acyclic and had dramatically depressed levels of prolactin cell activity. However, pinealectomy did not completely prevent this decline due to blinding unless the females continue to display estrous cyclicity. Thus, when pinealectomy was ineffective in preventing the loss of estrous cyclicity due to blinding, it was also ineffective in preventing declines in prolactin cell activity. In ovariectomized females, blinding caused a decline in prolactin cell activity. Pinealectomy was not consistently effective in preventing this decline after 12 weeks of treatment, although, in females blinded for 4 weeks (at which time all animals were cycling) and then ovariectomized for an additional 4 weeks, pinealectomy completely prevented this decline in prolactin cell activity. In a separate study, significant changes in prolactin cell activity during the estrous cycle were seen in untreated normally cycling female hamsters. These changes in prolactin mRNA, prolactin synthesis, and radioimmunoassayable prolactin in the pituitary were measured in the morning, when, consistent with other reports, no differences in serum prolactin were observed.
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DOPAMINE AS A DYNAMIC REGULATOR OF PROLACTIN SECRETION.FINDELL, PAUL RICHARD. January 1983 (has links)
To test the hypothesis that the hypothalamic tuberoinfundibular dopaminergic neuronal system plays a role in the dynamic regulation of pituitary prolactin secretion, its activity was correlated with experimentally-induced prolactin secretory episodes in the male rat. Direct estimates of tuberoinfundibular neuronal activity were made by measuring its rates of dopamine and norepinephrine synthesis or release. Prolactin secretion was assessed in vivo by measuring radioimmunoassayable prolactin levels in peripheral blood and the pituitary and in vitro by measuring prolactin concentrations released into incubation media. The anesthetic urethane and a substance isolated from the pineal gland were both demonstrated to inhibit prolactin secretion. Significant elevations of newly synthesized tuberoinfundibular dopamine were observed concomitant with this decreased prolactin secretion suggesting that acute increases in tuberoinfundibular dopaminergic neuronal activity were perhaps causally related to acute decreases in prolactin secretion since these substances were without a direct effect on the pituitary in vitro. Conversely, acute decreases in tuberoinfundibular neuronal activity induced by dopamine biosynthesis inhibition or mimicked by pituitary receptor blockade induced acute increases in prolactin secretion. As another prerequisite for its involvement in the dynamic regulation of prolactin secretion, the tuberoinfundibular neuronal system was demonstrated to be involved in the negative feedback control of prolactin over its own secretion. Elevated circulating prolactin levels produced by pituitary homografts transplanted beneath the kidney capsule accelerated tuberoinfundibular dopaminergic neuronal activity. In two unrelated experimental conditions, rats rendered blind and anosmic or hyperprolactinemic, the chronic inhibition of prolactin secretion was not associated with the maintenance of an increased tuberoinfundibular neuronal activity, but rather with a supersensitivity of the anterior pituitary to the prolactin-release-inhibitory action of dopamine. Long-lasting alterations in tuberoinfundibular dopaminergic neuronal activity appeared to induce this pituitary supersensitivity to dopamine. The tuberoinfundibular neuronal system appears to have the capacity to modulate prolactin secretory episodes via the alteration of its dopaminergic activity. Long-lasting alterations in this activity may induce changes in anterior pituitary sensitivity to dopamine essential for the chronic inhibition of pituitary prolactin secretion.
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The relationship of vitamin E to pituitary gland functionSnow, Milton Richard. January 1950 (has links)
Call number: LD2668 .T4 1950 S666 / Master of Science
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Effect of hormonal interaction on desensitization of the adrenocorticotropin response to arginine vasopressin in ovine anterior pituitary cells : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry at the University of Canterbury /Fan, Shujun. January 1900 (has links)
Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). "June 2006." Includes bibliographical references (leaves 67-75). Also available via the World Wide Web.
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The aggressive and water spitting behaviours in Canthigaster valentiniPan, Tai-An 04 September 2003 (has links)
The sharpnose pufferfish Canthigaster valentini is widespread over the Indo-Pacific tropical coral-reef region. The social system contains territorial male, non-territorial male, and territorial female. Territorial male always occupy a fixed territory and own several territorial females forming a harem in its territory. Previous researches were concerned about field observations or laboratory tests for agonistic respondences towards self-mirror stimuli. Research on dyad interaction is rarely seen in literature. The first objective of this study focuses on the agonistic interactions between two individuals from different combinations of the abovementioned (i.e., male-male and female-female) social categories under a more spacious laboratory condition. Characteristics for intra-individual behavioral sequences were described and compared. Besides, attentions were also paid to the possible factors (e.g., sex, social status) controlling the major aggressive display (i.e., Circling). The second objective is to conduct research on the water spitting behavior of this species that I had discovered. Factors including body size, presence of food and depth of water were tested to see if any of them is the releasing factor for this behavior. The amount of information transmitted in an intra-individual behavior sequence for a male winner was highest, whereas that for a female winner was lowest. Except for Circling, FRD, FLD, and HD were the other major aggressive behaviors. The average number of aggressive behavior in an intra-individual behavior sequence and display time for male were higher than that for female. More attacks were launched in female pairs than in male pairs. For female pairs, attacks were performed by both contestants , whereas only the winners attacked its opponent in male pairs. Male tended to launch the first attack after the longest Circling but that situation did not hold for female. Circling , a agonistic behavior nor quantitatively described in other studies, can be classified into S-type and C-type. The probability of occurrences for these two types of circling were not significant different. Cycle number was higher in the early phase of an aggressive interaction in male pairs. And male spent more time in circling during an aggressive interaction. Under the experimental setting of this study, body length did not affect the outcomes of a aggressive contest. For male pairs, ratio of body high/body length played a role in determining the outcomes. Presence of food , water depth, and movement of objects above the holding aquarium were all releasing factors for the water spitting behavior and presence of food might be the most important one.
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Desensitisation of the pituitary vasopressin receptor : development of a model system to assess involvement of G protein-coupled receptor kinase 5 : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry, University of Canterbury /Gatehouse, Michelle. January 2008 (has links)
Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 143-152). Also available via the World Wide Web.
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Isolation and developmental expression of growth hormone-releasing hormone (GRF), pituitary adenylate cyclase-activating polypeptide (PACAP) and their receptors in the zebrafish, Danio rerioFradinger, Erica Aileen 16 August 2018 (has links)
The growth and development of an organism requires the coordinated
actions of many factors. During development individual cells undergo
proliferation, migration and differentiation to form the adult organism. Two
structurally related members of the glucagon superfamily, growth hormone releasing
hormone (GRF) and pituitary adenylate cyclase-activating polypeptide
(PACAP), are thought to modulate vertebrate development. In mammals, GRF
modulates the development of pituitary somatotrophs and the release of fetal
growth hormone. In contrast, PACAP appears to have a more general role during
development. PACAP may be involved in the patterning of the embryonic axis and
in the development of the neural tube. The objectives of my study were to isolate
GRF, PACAP and their receptors from the zebrafish, characterize their expression
in the developing embryo and adult embryo and examine the role of PACAP during
brain development.
To study the role of GRF and PACAP, I isolated a genomic clone encoding
the GRF and PACAP peptides from the zebrafish genomic library and
characterized its gene copy number and adult tissue expression pattern. The GRF-PACAP
gene isolated from the zebrafish was comprised of five exons with the
GRF peptide encoded on the fourth exon and the PACAP peptide encoded on the
fifth exon. This gene structure is similar to that found in other non-mammalian
vertebrates and supports the hypothesis that the gene duplication leading to the
encoding of the GRF and PACAP peptides on separate genes occurred later in
evolution. In addition, the zebrafish genome was found to contain only one copy of
the GRF-PACAP gene. The GRF-PACAP gene was widely expressed in the adult
zebrafish in tissues developmentally derived from all three germ layers, suggesting
that the gene may be widely expressed in the embryo as well.
To examine the functional significance of the co-expression of GRF and
PACAP in zebrafish, I isolated the GRF and PACAP receptors and characterized
their expression pattern. I isolated three distinct cDNAs from zebrafish encoding
the GRF receptor, the PACAP specific PAC1 receptor and the shared vasoactive
intestinal peptide/PACAP receptor VPAC1. In addition, four isoforms of the PAC1
receptor were isolated from zebrafish including a novel isoform found in the gill.
All three receptors were widely expressed in adult zebrafish and receptors for both
GRF and PACAP were found in most tissues. This indicates that GRF and PACAP
may modulate each other’s function.
To determine the developmental role of GRF and PACAP, I characterized
the expression pattern of the GRF-PACAP gene and the GRF, PAC1 and VPAC1
receptors in the zebrafish embryo. The GRF and PAC1 receptors are the earliest to
be expressed in development starting at the cleavage stage. Later, the GRF-PACAP
gene and the VPAC1 receptor are first expressed at the late blastula/early gastrula
stage in the zebrafish and are expressed throughout the developmental period.
Strong expression of the GRF, PACAP and their receptors during mid gastrulation
indicates that these peptides may be involved in modulating the formation of the
embryonic axis. During the segmentation period the GRF-PACAP gene is widely
expressed in the zebrafish embryo and the PAC1 receptor short and hop isoforms
are differentially expressed. Therefore, PACAP may regulate cell cycle exit or cell
proliferation through activation of different PAC1 receptor isoforms during the
segmentation stage. In the subsequent pharyngula period, the GRF-PACAP
transcript is localized mainly to the hatching gland. However, expression is seen
also in tissues that undergo differentiation during this stage. Therefore, the timing
of the expression of the GRF-PACAP gene indicates that it may be involved in early
patteming events and promoting cell cycle exit prior to differentiation. To
investigate the role of GRF and PACAP in the developing brain, I localized the
expression of GRF, PACAP and the PAC1 receptor in neuroblasts derived from an
embryonic day 3.5 chick. PACAP was found to stimulate the cAMP pathway in
these cells, indicating that PACAP may modulate brain development. This work
indicates that GRF and PACAP play an important role in vertebrate development. / Graduate
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Developmental expression and evolution of growth hormone-releasing hormone and pituitary adenylate cyclase-activating polypeptide in teleost fishes, rainbow trout (Oncorhynchus mykiss) and zebrafish (Danio rerio)Krueckl, Sandra Lea 06 July 2018 (has links)
Growth hormone-releasing hormone (GRF) and pituitary adenylate cyclase-activating
polypeptide (PACAP) are members of the PACAP/Glucagon superfamily. The
family is proposed to have developed from an ancestral PACAP-like molecule in
invertebrates. Through successive exon, gene and genome duplications the family has
grown to include seven other members. In mammals GRF and PACAP are located on
different genes, but in fish, amphibians and birds they are located on the same gene. The
main function of GRF is the release of growth hormone (GH) from the pituitary. Also,
during development GRF influences the fetal pituitary and stimulates GH release during
late gestation. In contrast, the functions of PACAP are extremely varied. PACAP is the
newest member of the superfamily and there is still much work to be done before its
actions are well understood. Like GRF, PACAP is a releasing hormone acting on the
pituitary and in addition, the adrenal gland, pancreas and heart, as well as other organs.
Also, PACAP regulates smooth muscle in the vascular system, gut, respiratory tract and
reproductive tract During development PACAP affects proliferation, differentiation and
apoptosis.
GRF and PACAP are expressed throughout development in fish, beginning during
the blastula period in rainbow trout and at the end of gastrulation in zebrafish (earliest stage
examined). In rainbow trout the grf/pacap gene is expressed as two transcripts, a short and
a long transcript. The short transcript is produced by alternative splicing of the gene and
does not include the fourth exon which codes for GRF. The long transcript includes the coding regions for both GRF and PACAP. By this means PACAP can be regulated
separately from GRF. With the extensive role PACAP appears to play in development,
separate regulation of the hormone may be necessary. Expression of the grf/pacap gene in
zebrafish is widespread early in development and gradually becomes localized. Of particular interest is the expression of the grf/pacap transcript in regions associated with the
prechordal plate, an important organizing center in development. Although it is not yet
confirmed, there is evidence to suggest GRF and PACAP are expressed in the prechordal
plate and its derivatives in the gut and hatching gland. In addition, expression of the
grf/pacap transcript is observed in the neuroectoderm (eye, brain and spinal cord) and the
developing heart. Considering the expression pattern of GRF and PACAP, I propose that
one of both of these hormones may be involved in patterning during vertebrate
embryogenesis.
The evolution of gene families is thought to occur through successive exon, gene and genome duplications. Duplicate exons or genes become differentiated and eventually
gain new functions or become functionless. During evolution of the grf/pacap lineage,
several duplication events have occurred. Analysis of rainbow trout leads me to think that
this fish and other salmonids possess two copies of the grf/pacap gene. This is not
unexpected considering the tetraploid nature of salmonids. Present day mammals encode
GRF and PACAP on separate genes. At some point during the evolution of this lineage a
duplication event has occurred, possibly in early mammals or prior to the divergence of
birds. The study of multigene families is a useful way to understand evolutionary
processes. To this end I examined three members of multigene families from sockeye
salmon. Therefore, in addition to the evolutionary mechanisms and pathways that directed
grf/pacap gene evolution, I examined the ferritin-H subunit, the alpha-tubulin subunit and
the beta-globin subunit. These cDNA sequences are similar to their counterparts in other
teleost. The evolution of the ferritin gene family is particularly interesting because it
involves the addition or deletion of DNA sequences that affect regulation and cytosolic
location. / Graduate
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