Developmental Anatomy of the Pituitary Fossa
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
There is a saccular depression in the roof of the stomodeum immediately in front of the oropharyngeal membrane. This saccular depression evaginates to form the pouch of Rathke. This area remains in close contact with the ventral surface of the forebrain. The pouch of Rathke develops into the adenohypophysis. The anterior part becomes the pars anterior and the posterior part, in contact with the forebrain, becomes the pars intermedia. The section of the forebrain in close contact with the pars intermedia becomes the neurohypophysis (Figure 54.1). In foetal life and childhood the vestige of Rathke’s pouch remains as the hypophyseal cleft separating the pars anterior and pars intermedia. The pars intermedia is rudimentary in humans and is of little functional significance. Remnants of Rathke’s pouch may persist below the sphenoid in the roof of the nasopharynx forming a pharyngeal pituitary. The clivus and the dorsum sellae of the future sphenoid bone are formed from mesenchymal condensations surrounding the hypophysis.1 The cavernous sinus is derived from the primary head vein (Figure 54.1).
Endocrine Glands
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Loss of anterior pituitary cell mass can occur under circumstances of reduced demand, and this loss may be associated with reduced weight. Aging in rats is associated with a reduction in the hypothalamic content of releasing hormones and the capacity of the pituitary to synthesize or release FSH, LH, and TSH; these differences may be partly due to differences in pituitary tumor incidence and their space occupying effects (Bedrak et al. 1983; Chen 1984). Physiological alterations that result in increased activity of the hypothalamus, such as water deprivation or lactation, may result in involution of the pars intermedia. Rats administered with bromocriptine, a dopamine receptor agonist, decreased the cell number and thickness of the pars intermedia in association with reduction in synthesis of pro-opiomelanocortin–derived peptides and mRNA (Chronwall et al. 1987).
Corticotropin and Melanotropin
Paul V. Malven in Mammalian Neuroendocrinology, 2019
The hormonal secretions of the pars intermedia have been studied most extensively in submammalian species, especially fish, amphibians, and reptiles. It has been known for many years that the pars intermedia of these species secretes melanocyte-stimulating hormone which, for purposes of uniform nomenclature in this book, will be called melanotropin and abbreviated MSH. The bioactivity of MSH involves activation of melanocyte cells in the dermis of the skin. MSH acts to disperse intracellular granules of melanin within melanocytes, which results in a darkening of the skin.
Nonclinical safety evaluation, pharmacokinetics, and target engagement of Lu AF82422, a monoclonal IgG1 antibody against alpha-synuclein in development for treatment of synucleinopathies
Published in mAbs, 2021
Lone Fjord-Larsen, Annemette Thougaard, Karen Malene Wegener, Joan Christiansen, Frank Larsen, Lise Maj Schrøder-Hansen, Marianne Kaarde, Dorte Kornerup Ditlevsen
The pars nervosa of the pituitary showed positive staining in most samples where present, and positive staining of the pars intermedia was seen in rats. This is in line with previous reporting of alpha-synuclein expression in the pituitary.35 Other cells with previous reporting of alpha-synuclein expression and showing specific staining with at least one of the two antibodies included chromaffin cells of the adrenal medulla in humans and cynomolgus monkeys (expression reported in the adrenal gland36), scattered cells of the splenic red pulp in humans and cynomolgus monkeys (immunostaining in spleen previously described37), isolated incidences of positive staining in sinus cells of the lymph nodes in cynomolgus monkeys, scattered cells of the bone marrow in rats and basal epidermal cells in human skin (consistent with previous reports of alpha-synuclein expression in skin and bone marrow37). Though the staining observed in non-nervous tissues was not necessarily seen in all species or with both antisera used, the previous reporting of alpha-synuclein expression in these tissues suggest that the observed staining represent expression of alpha-synuclein.
Aplasia of the Optic Nerve: A Report of Seven Cases
Published in Neuro-Ophthalmology, 2020
Yujia Zhou, Maura E. Ryan, Marilyn B. Mets, Hawke H. Yoon, Bahram Rahmani, Sudhi P. Kurup
A 2-month-old, full-term girl presented with irregular pupils and asymmetric eyes. Pregnancy was notable for maternal smoking during the second and third trimesters. Bilaterally, there was a glial opacity with abnormal vessels around the rim in the typical location of the optic nerve head. The fundus also displayed scattered, lacunae-like chorioretinal coloboma (Figure 1h). Both eyes were microphthalmic with microcornea with associated haze and thick pachymetry (Figure 1d). On the MRI, there was a small pars intermedia cyst, favoured to be incidental, and a hypoplastic dorsal C1 arch with associated craniovertebral junction stenosis. She underwent posterior fossa decompression at the age of 10 months. Surveillance showed an unchanged pituitary cyst size, and she has had no endocrinologic dysfunction. Aicardi syndrome was ruled out due to the patient’s normal chromosomal microarray and absence of dermatological findings and seizures. Neurologic evaluation noted delays in visual-dependent skills. At the time of this report, the patient was healthy at 5 years old and has had subsequent imaging demonstrating an unremarkable skull base.
Photoperiod-dependent changes in oxidative stress markers in the blood of Shetland pony mares and stallions involved in recreational horseback riding
Published in Chronobiology International, 2022
Natalia Kurhaluk, Oleksandr Lukash, Halyna Tkachenko
The physiological mechanisms of season-induced dependencies are defined as follows. One is associated with the time of year, when the length of day (or photoperiod) is mediated by the effects of the epiphysis hormone melatonin. Equally important is the second factor corresponding to endogenous annual rhythms (Paul et al. 2008). These rhythms are modified by environmental signals, adapting to seasonal processes with changes in the photoperiod or other external environmental signals. Melatonin levels are determined by species-specific genetic mechanisms (Guillaume et al. 2006; Singh et al. 2019). Many hormonal signals take part in homeostasis in different seasons. For instance, the nocturnal rises in plasma melatonin concentrations vary across seasons at the winter and summer solstices and in autumn and spring (Haritou et al. 2008); concentrations of other circadian markers (serotonin, dopamine, and cortisol) in peripheral plasma were determined also in the case of equine pituitary pars intermedia dysfunction.
Related Knowledge Centers
- Pituitary Gland
- Colloid
- Cyst
- Basophil Cell
- Chromophobe Cell
- Rathke'S Pouch
- Fetus
- Melanocyte-Stimulating Hormone