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Evaluation and Investigation of Pituitary Disease
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
The pituitary gland sits within the sella turcica of the sphenoid bone, inferior to the hypothalamus and optic chiasm. It is surgically accessible transnasally via the sphenoid sinus. The gland is composed of two lobes. The anterior pituitary (adenohypophysis) secretes luteinising hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), and prolactin. The posterior pituitary (neurohypophysis) is not a gland in itself, but a projection of the hypothalamus, and it releases antidiuretic hormone (ADH) and oxytocin. It is connected to the hypothalamus above by the pituitary stalk (infundibulum), which passes through the diaphragm that forms the roof of the sella. The function of the anterior pituitary is controlled chiefly by hypothalamic hormonal control; the hypothalamic-pituitary-peripheral axis is regulated by multiple feedback loops.
Principles of Pathophysiology of Infertility Assessment and Treatment*
Published in Asim Kurjak, Ultrasound and Infertility, 2020
Joseph G. Schenker, Aby Lewin, Menashe Ben-David
The adenohypophysis is an intermediate member in a dynamic relationship between the hypothalamus and the peripheral gonadal glands. The adenohypophysis modulates the function of both the gonads and the hypothalamus via a “short loop” mechanism. In turn, the pituitary is affected by hormonal signals from both the hypothalamus and the peripheral gonads. The pituitary is affected not only by the hypothalamic Gn-RH, but also by the hypothalamic dopamine, which in turn regulate the synthesis and release of FSH, LH, and prolactin, each of which can affect gonadal function.
The Pituitary Gland Eva Nagy
Published in Istvan Berczi, Pituitary Function and Immunity, 2019
The pituitary gland is located in the base of the skull in the sella turcica, a cavity within the sphenoid bone, and is attached to the hypothalamus with a stalk. The pituitary is a small organ; it weighs about 0.5 g in man and it may approach 1 g in weight during pregnancy. We distinguish the anterior lobe of pituitary that is also called adenohypophysis, and the posterior lobe, or neurohypophysis, and an intermediate portion or pars intermedia. The anterior lobe amounts to approximately 75% of the total weight of the gland. The pars intermedia is missing or is present in traces (2%) in man. The pituitary gland is embryologically derived from cells of both stomodeal ectoderm (Rathke’s pouch) and neural ectoderm of the floor of the forebrain.5 By the 12th week of intrauterine life, the pituitary is identifiable macroscopically, secretory granules appear in the cytoplasm of adenohypophyseal cells, and pituitary hormones can be detected by radioimmunoassay.
Histopathological evaluation of the effects of dexmedetomidine against pituitary damage ınduced by X-ray irradiation
Published in Biomarkers, 2023
Filiz Mercantepe, Levent Tumkaya, Tolga Mercantepe, Sema Rakici
In neurohypophyseal tissues of rats in the radiation group of our study; vascular congestion, oedematous areas, and neurons with pyknotic nuclei were observed. Similarly, extensive oedematous areas, vascular congestion, and chromophobic and chromophilic cells with pyknotic nuclei were observed in the pars distalis of the adenohypophysis. To our knowledge, there are no histopathological studies in the literature that have investigated radiation-induced pituitary damage. However, there are publications in the literature reporting that radiation causes dysfunction of one or more pituitary hormones in the HPA (Samaan et al.1982, Lıttley et al.1989, Lebaron-Jacobs et al.2004, Agha et al.2005, Darzy 2009, 2013, Appelman-Dijkstra et al.2011, Sathyapalan and Dixit 2012, Xu et al.2020). Radiation-induced pituitary damage may occur after cranial irradiation in which the pituitary enters the radiation field, as well as anterior pituitary hormone deficiencies after whole-body irradiation before bone marrow transplantation used to treat childhood leukemias (Darzy 2009, 2013, Sathyapalan and Dixit 2012). In the present study, especially the whole-body irradiation method was preferred due to the increasing application of bone marrow transplantation.
Growth hormone improved oxidative stress in follicle fluid by influencing Nrf2/Keap1 expression in women of advanced age undergoing IVF
Published in Gynecological Endocrinology, 2022
Zhaoyan Nie, Na Zhang, Lina Guo, Cuiting Lv, Yi Zhang, Congmin Wang, Haifeng Wu
Growth Hormone (GH), secreted by adenohypophysis cells, has attracted significant attention due to the possibility that GH might enhance fertility. GH binds to the GH receptor (GHR), which augments the effects of gonadotropin (Gn) on GCs and thecal cells and improves follicle development [5]. For this reason, GH has been widely applied to treat pathologies associated with OS. GH exerted beneficial effects by enhancing antioxidant defenses and reducing oxidative stress in myocardial cells in rats [6]. GH acts as an antioxidant that contributes to ovarian health [7]. GH showed a radioprotective effect and rescued the ovarian reserve by counteracting oxidative stress-mediated apoptosis [8]. GH protects against GC apoptosis by alleviating oxidative stress and enhancing mitochondrial function [9]. In poor ovarian responders, GH alleviates OS and improves the IVF outcome [10]. Studies have shown that GH administration improves oocyte quality and IVF outcome in older women and/or patients with poor ovarian response [11]. GH supplementation may improve the pregnancy rate and endometrial receptivity in women aged more than 40 years undergoing IVF-ET [12]. However, the mechanisms by which GH improves IVF outcomes in advanced age have not yet been clarified.
The neuro control of the ovarain cycle – a hypothesis
Published in Gynecological Endocrinology, 2018
It was only in 1955 that Harris showed through a series of elegant experiments that ‘the hypothalamo–hypophysial portal vasculature is necessary for the maintenance and control of normal activity of the anterior pituitary’. He proposed that ‘that nerve fibers from the hypothalamus liberate some humoral substance(s) into the capillaries of the primary plexus in the median eminence [8]. Harris stated three requirements that must be met for a compound to be accepted as a releasing factor of adenohypophysial hormones:(a) show this substance is present in the blood in the hypophysial portal vessels in greater amount than in systemic blood,(b) show that the concentrations of this substance in the blood of the hypophysial portal vessels varies according to electrical or reflex activation of the hypothalamic nerve tracts,(c) demonstrate that activity of the adenohypophysis is correlated with this varying concentration.