China
Africa
Explore chapters and articles related to this topic
Summation of Basic Endocrine Data
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
The pituitary gland is at the base of the brain, in a depression called the sella turcica. It is connected to the hypothalamus above by a hypophyseal stalk. The gland is divided into an anterior lobe (adenohypophysis) and a posterior lobe (neurohypophysis), and between them a small structure called the pars intermedia. The posterior lobe hormones are manufactured first in the hypothalamus and then transported through a neurosecretory pathway to the posterior lobe where they are stored.
Corticotropin and Melanotropin
Published in Paul V. Malven, Mammalian Neuroendocrinology, 2019
Hormonal secretion from the pars intermedia (primarily α-MSH and acetylated forms of β-endorphin) is under the inhibitory influence of the hypothalamus mediated by secretomotor innervation involving dopamine and perhaps other aminergic neurotransmitters (Jackson and Lowry, 1983). Surgical disconnection of the hypothalamus and hypophysis in sheep increased the quantities of MSH and acetylated β-endorphin in the neurointermediate lobe which included the pars intermedia. Administration of dopamine agonist drugs to such operated sheep partially reversed the effects of hypothalamic disconnection (Smith et al., 1989). Many of the dopaminergic axons that innervate the pars intermedia originate in the periventricular area of the hypothalamus (Goudreau et al., 1992). In summary, synthesis and secretion of POMC-derived peptides in the pars intermedia appears to be tonically inhibited by hypothalamic axons that release dopamine at their terminals. Secretomotor innervation to regulate these cells is consistent with the poorly vascularized nature of the pars intermedia tissue relative to the extreme vascularity of the pars anterior tissue. Moreover, adrenocortical hormones from the adrenal gland which feedback and inhibit corti- cotroph cells of the pars anterior do not regulate the POMC cells of the pars intermedia.
Major Digestive and Endocrine Glands
Published in George W. Casarett, Radiation Histopathology: Volume II, 2019
The pars intermedia contains basophile cells, which extend into the neural lobe, and chromophobe cells. The abundant capillaries of this part are continuous with the capillary bed of the neural lobe and with the sinusoids of the anterior lobe. The pars intermedia secretes under neural control a hormone called intermedin, which causes expression of melanocytes and darkening of the skin. The pars tuberalis contains cords of cuboidal columnar cells of no known hormonal function and some acidophile and basophile cells.
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.
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.