scholarly journals Maternal photoperiod programs hypothalamic thyroid status via the fetal pituitary gland

2017 ◽  
Vol 114 (31) ◽  
pp. 8408-8413 ◽  
Author(s):  
Cristina Sáenz de Miera ◽  
Béatrice Bothorel ◽  
Catherine Jaeger ◽  
Valérie Simonneaux ◽  
David Hazlerigg
Keyword(s):  
Pituitary Gland ◽  
Thyroid Stimulating Hormone ◽  
Day Length ◽  
Ependymal Cells ◽  
Pars Tuberalis ◽  
Phenotypic Flexibility ◽  
Calendar Time ◽  
Wild Mammals ◽  
Melatonin Production

In wild mammals, offspring development must anticipate forthcoming metabolic demands and opportunities. Within species, different developmental strategies may be used, dependent on when in the year conception takes place. This phenotypic flexibility is initiated before birth and is linked to the pattern of day length (photoperiod) exposure experienced by the mother during pregnancy. This programming depends on transplacental communication via the pineal hormone melatonin. Here, we show that, in the Siberian hamster (Phodopus sungorus), the programming effect of melatonin is mediated by the pars tuberalis (PT) of the fetal pituitary gland, before the fetal circadian system and autonomous melatonin production is established. Maternal melatonin acts on the fetal PT to control expression of thyroid hormone deiodinases in ependymal cells (tanycytes) of the fetal hypothalamus, and hence neuroendocrine output. This mechanism sets the trajectory of reproductive and metabolic development in pups and has a persistent effect on their subsequent sensitivity to the photoperiod. This programming effect depends on tanycyte sensitivity to thyroid stimulating hormone (TSH), which is dramatically and persistently increased by short photoperiod exposure in utero. Our results define the role of the fetal PT in developmental programming of brain function by maternal melatonin and establish TSH signal transduction as a key substrate for the encoding of internal calendar time from birth to puberty.

scholarly journals Molecular basis for regulating seasonal reproduction in vertebrates

2016 ◽  
Vol 229 (3) ◽  
pp. R117-R127 ◽  
Author(s):  
Taeko Nishiwaki-Ohkawa ◽  
Takashi Yoshimura
Keyword(s):  
Thyroid Hormone ◽  
Pituitary Gland ◽  
Environmental Changes ◽  
Thyroid Stimulating Hormone ◽  
Day Length ◽  
Adaptive Behaviors ◽  
Seasonal Reproduction ◽  
Pars Tuberalis ◽  
Light Detection ◽  
Stimulating Hormone

Animals that inhabit mid- to high-latitude regions exhibit various adaptive behaviors, such as migration, reproduction, molting and hibernation in response to seasonal cues. These adaptive behaviors are tightly regulated by seasonal changes in photoperiod, the relative day length vs night length. Recently, the regulatory pathway of seasonal reproduction has been elucidated using quail. In birds, deep brain photoreceptors receive and transmit light information to the pars tuberalis in the pituitary gland, which induces the secretion of thyroid-stimulating hormone. Thyroid-stimulating hormone locally activates thyroid hormone via induction of type 2 deiodinase in the mediobasal hypothalamus. Thyroid hormone then induces morphological changes in the terminals of neurons that express gonadotropin-releasing hormone and facilitates gonadotropin secretion from the pituitary gland. In mammals, light information is received by photoreceptors in the retina and neurally transmitted to the pineal gland, where it inhibits the synthesis and secretion of melatonin, which is crucial for seasonal reproduction. Importantly, the signaling pathway downstream of light detection and signaling is fully conserved between mammals and birds. In fish, the regulatory components of seasonal reproduction are integrated, from light detection to neuroendocrine output, in a fish-specific organ called the saccus vasculosus. Various physiological processes in humans are also influenced by seasonal environmental changes. The findings discussed herein may provide clues to addressing human diseases, such as seasonal affective disorder.

Posttraumatic Anterior Hypopituitarism—Revisited: The Role of TRH Provocative Release of Prolactin in the Confirmation of Anterior Pituitary Damage

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 948-950
Author(s):  
David R. Brown ◽  
J. Michael McMillin
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Thyroid Stimulating Hormone ◽  
Anterior Pituitary Gland ◽  
Serum Prolactin ◽  
Pituitary Insufficiency ◽  
Closed Head Trauma ◽  
One Year ◽  
Stimulating Hormone

We have previously reported a case of anterior pituitary insufficiency in a 14-year-old girl following closed head trauma.1 Endocrine evaluation one year after her accident revealed hypopituitarism manifested by cachexia, hypothyroidism, hypogonadism, and hypoadrenocorticism. Laboratory studies demonstrated deficiencies of adrenocorticotropic hormone, thyroid-stimulating hormone (TSH), growth hormone, and gonadotropic hormones (follicle-stimulating hormone and luteinizing hormone). We postulated that her hypopituitarism was due to anterior pituitary gland destruction rather than stalk section or hypothalamic damage. We have recently measured her serum prolactin concentrations following provocative stimulation with thyrotropin-releasing hormone (TRH), and these results strengthen the evidence for direct anterior pituitary gland destruction and provide a more complete delineation of her endocrinologic function.

Pituitary tumours

2019 ◽  
pp. 299-320
Author(s):  
Kanna Gnanalingham ◽  
Zsolt Zador ◽  
Tara Kearney ◽  
Federico Roncaroli ◽  
H. Rao Gattamaneni
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Horizontal Plane ◽  
Third Ventricle ◽  
Sella Turcica ◽  
Thyroid Stimulating Hormone ◽  
Posterior Lobe ◽  
Recommended Treatment ◽  
Stimulating Hormone

The pituitary gland occupies the sella turcica, approximately 5 cm posterior to the tip of the nose in the midline of the skull base. It is closely related to the hypothalamus and third ventricle superiorly, chiasm and lamina terminalis anterosuperiorly, sphenoid sinus anteroinferiorly, cavernous sinus and cavernous segment of the carotid artery laterally, the posterior clinoids and clivus posteriorly. There are two distinct components to the pituitary gland, the anterior and posterior lobe, which are derived from the ectoderm and neuroectoderm, respectively. The anterior pituitary constitutes 80% of the gland mass and in the horizontal plane it is distributed into two lateral wings. The hormones produced by the anterior pituitary are adrenocorticotropic hormone, prolactin, growth hormone, thyroid-stimulating hormone, follicle-stimulating hormone, and luteinizing hormone. This chapter looks in detail at the role of the pituitary gland, what happens when it becomes tumorous, and the recommended treatment avenues.

The Pituitary Gland: Embryology, Physiology, and Pathophysiology

2000 ◽  
Vol 19 (2) ◽  
pp. 9-17 ◽  
Author(s):  
Angela Dorton
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Pars Intermedia ◽  
Pituitary Hormone ◽  
Pars Tuberalis ◽  
Pars Distalis ◽  
Stimulating Hormone

The pituitary gland, the “master gland” of the body, is composed of endocrine cells, which secrete hormones essential for homeostasis. The gland consists of the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary), two unique structures that differ anatomically and functionally.The neurohypophysis is innervated by nerve cells in the hypothalamus and forms the connection between it and the pituitary gland. The hypothalamus stimulates release and inhibition of pituitary hormones. The neurohypophysis secretes oxytocin and antidiuretic hormone.The adenohypophysis is composed of three structures: the pars distalis, the pars intermedia, and the pars tuberalis. The anterior pituitary (pars distalis) is responsible for the release of hormones that include growth hormone, prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, and melanocyte-stimulating hormone.Disorders of the pituitary are predominately those of insufficient hormone release and may have profound effects on the neonate. The potential causes of and clinical symptomatology that may accompany pituitary hormone insufficiency in the neonatal period are explored.

scholarly journals Clocks for all seasons: unwinding the roles and mechanisms of circadian and interval timers in the hypothalamus and pituitary

2014 ◽  
Vol 222 (2) ◽  
pp. R39-R59 ◽  
Author(s):  
Shona Wood ◽  
Andrew Loudon
Keyword(s):  
Third Ventricle ◽  
Day Length ◽  
Ependymal Cells ◽  
Pars Tuberalis ◽  
Molecular Events ◽  
Timing System ◽  
Molecular Signals ◽  
The Brain ◽  
Sustained Increase

Adaptation to the environment is essential for survival, in all wild animal species seasonal variation in temperature and food availability needs to be anticipated. This has led to the evolution of deep-rooted physiological cycles, driven by internal clocks, which can track seasonal time with remarkable precision. Evidence has now accumulated that a seasonal change in thyroid hormone (TH) availability within the brain is a crucial element. This is mediated by local control of TH-metabolising enzymes within specialised ependymal cells lining the third ventricle of the hypothalamus. Within these cells, deiodinase type 2 enzyme is activated in response to summer day lengths, converting metabolically inactive thyroxine (T4) to tri-iodothyronine (T3). The availability of TH in the hypothalamus appears to be an important factor in driving the physiological changes that occur with season. Remarkably, in both birds and mammals, the pars tuberalis (PT) of the pituitary gland plays an essential role. A specialised endocrine thyrotroph cell (TSH-expressing) is regulated by the changing day-length signal, leading to activation of TSH by long days. This acts on adjacent TSH-receptors expressed in the hypothalamic ependymal cells, causing local regulation of deiodinase enzymes and conversion of TH to the metabolically active T3. In mammals, the PT is regulated by the nocturnal melatonin signal. Summer-like melatonin signals activate a PT-expressed clock-regulated transcription regulator (EYA3), which in turn drives the expression of the TSHβ sub-unit, leading to a sustained increase in TSH expression. In this manner, a local pituitary timer, driven by melatonin, initiates a cascade of molecular events, led byEYA3, which translates to seasonal changes of neuroendocrine activity in the hypothalamus. There are remarkable parallels between this PT circuit and the photoperiodic timing system used in plants, and while plants use different molecular signals (constans vsEYA3) it appears that widely divergent organisms probably obey a common set of design principles.

The Role of Zinc in Thyroid Hormones Metabolism

2019 ◽  
Vol 89 (1-2) ◽  
pp. 80-88 ◽  
Author(s):  
Juliana Soares Severo ◽  
Jennifer Beatriz Silva Morais ◽  
Taynáh Emannuelle Coelho de Freitas ◽  
Ana Letícia Pereira Andrade ◽  
Mayara Monte Feitosa ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Scientific Evidence ◽  
Thyroid Stimulating Hormone ◽  
Zinc Transporters ◽  
Serum Concentrations ◽  
Metabolic Adaptations ◽  
Serum T3 ◽  
Regulatory Effects ◽  
Shed Light

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

Primary Amenorrhoea with Pituitary Dwarfism: A rare case report

2016 ◽  
Vol 2 (2) ◽  
pp. 145-147
Author(s):  
Siva S ◽  
Divya Gopineni ◽  
Shafi P ◽  
Chandra Sekhar
Keyword(s):  
Pituitary Gland ◽  
General Medicine ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Primary Amenorrhea ◽  
Pituitary Dwarfism ◽  
Primary Amenorrhoea ◽  
Sexual Characteristics ◽  
Loss Of Appetite ◽  
Secondary Sexual

Females with pituitary dwarfism and a multiple deficiency of pituitary hormones show ovarian dysfunction due to hypogonadotropism. Primary amenorrhea can be diagnosed if a patient has normal secondary sexual characteristics but no menarche by 16 years of age. A 16 year-old female patient admitted in general medicine department with chief complaints of shortness of breath on exertion since 15 days, swelling of both legs since 10 days, loss of weight since 5 months, loss of appetite since 3 months, history of pain during swallowing. Pelvis scan examination reveals that uterus measures 3.2×0.5×0.5cm; uterus is hypo plastic, ovaries not visualized. Patient parents reveled that from patient birth to 11years of age her growth and other developments were normal, after that her growth is stopped and no changes were observed in development since 5 years. Patient has hypothyroidism so pituitary gland make an important role to maintain hormone levels, pituitary gland produces thyroid stimulating hormone (TSH) which stimulates thyroid gland to produce thyroid hormones. Primary Amenorrhea, short stature and poorly developed secondary sexual characters which could have been contributed and should be subjected for karyotyping. This type of Pituitary Dwarfism is very difficult to manage.

Role of Panchakarma in the management of Hypothyroidism

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Dr.Suraj Kumbar ◽  
Dr.Lohith BA ◽  
Dr.Ashvinikumar M ◽  
Dr. Amritha R ◽  
Dr. Shameem Banu
Keyword(s):  
Metabolic Rate ◽  
Pituitary Gland ◽  
Life Style ◽  
The Body ◽  
Management Guidelines ◽  
Quality Of Food ◽  
Sedentary Life ◽  
Sedentary Life Style

We are in technical era where there is more of sedentary life style and stress along with this urbanization is affecting our quality of food and health. This is leading to many lifestyle disorders and hormonal imbalances in our body. Hypothyroidism one among the endocrinal disorder. Thyroid is an endocrinal gland secrets T3 and T4 hormones regulated by TSH which is secreted by Pituitary gland. These hormones have two major effects on the body, 1) To increase the overall metabolic rate in the body 2) To stimulate growth in children. Hypothyroidism is common health issue in India. The highest prevalence of hypothyroidism (13.1%) is noted in people aged 46-54yrs old. With people aged 18-35 yrs being less affected (7.5%). To prevent these hazards Panchakarma is beneficiary to maintain metabolic rate. Here an attempt is made to diagnose hypothyroidism in the light of Ayurveda and management guidelines through Panchakarma.

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