Neuroendocrine Morphology
Paul V. Malven in Mammalian Neuroendocrinology, 2019
The unique morphological aspects of the hypophysis (also known as the pituitary gland) provided some of the earliest clues to the discipline that would become known as Neuroendocrinology. Moreover, the following descriptions of hypophysial morphology in different species (Purves, 1961) will provide the basis for later understanding of neuroendocrine mechanisms. The hypophysis is divided into neurohypophysis and adenohypophysis based on embryological development from neural and epithelial substrates, respectively. Adenohypophysial tissue (pars tuberalis, pars intermedia, and pars anterior) develops specifically from an outgrowth of ectodermal epithelium of the primitive oral cavity called Rathke’s pouch. The neural tissue denoted in Figure 2-1 represents the entire neurohypophysis consisting of pars eminens and pars nervosa. Although these neural tissues could be categorized as either hypothalamus or hypophysis, most modem authors classify pars nervosa as part of the hypophysis and pars eminens as part of the hypothalamic infundibulum, where it is also known as the median eminence. The demarcation between pars eminens and pars nervosa cannot be precisely defined, but it occurs somewhere in the hypophysial stalk.
The endocrine system
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella in Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
As discussed previously, the neurohypophysis has a direct anatomical connection to the hypothalamus. Therefore, the hypothalamus regulates the release of hormones from the neurohypophysis by way of nerve signals. Action potentials generated by the neurosecretory cells originating in the hypothalamus are transmitted down the neuronal axons to the nerve terminals in the neurohypophysis and stimulate the release of the hormones into the blood. The tracts formed by these axons are referred to as the hypothalamic-hypophyseal tracts (see Figure 11.2). The action potentials are initiated by various forms of sensory input to the hypothalamus. Specific forms of sensory input that regulate the release of ADH and oxytocin are described in subsequent Section 11.9, Neurohypophysis.
Physiology of the Pituitary Gland
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
The posterior lobe of the pituitary gland, the neurohypophysis, consists of nerve fibres originating from the supraoptic and paraventricular nuclei of the hypothalamus. The supraoptic and paraventricular nuclei synthesize two cyclic nonapeptides. The resulting hormones are known as arginine vasopressin (AVP, previously known as antidiuretic hormone, ADH) and oxytocin, respectively (Figure 56.10). The hormones are transported to the posterior lobe of the pituitary gland via the pituitary stalk, loosely bound to their carrier protein neurophysin. Within the posterior lobe of the pituitary, nerve axon terminals are located close to blood vessels. Upon activation, the secretory granules rapidly release the hormones by a calcium-dependent exocytic process,2 allowing them to diffuse into the local capillary network. The role of AVP in rapid ACTH release has been well described.2
Pre- and post-clinical–radiological and surgical evaluation of patients with pituitary adenoma and metabolic syndrome
Published in International Journal of Neuroscience, 2023
R. Flores-Rabasa, J. A. González-Almazán, A. P. Cortés-Contreras, L. A. Méndez-García, F. Velasco, J. L. Navarro-Olvera, G. Aguado-Carrillo, A. Benítez-Gasca, J. D. Carrillo-Ruiz
In the Department of Pathology, tumor samples were stained with hematoxylin–eosin. Reticulin staining was used in this study. Subsequently, a classic immunohistochemistry (IHC) test was performed using synaptophysin. The neurofilament-labeling technique was used to confirm the presence of the posterior pituitary. Regarding the adenohypophyseal hormones required for PAs subtyping, IHC panels for antibodies to prolactin (PRL), growth hormone (GH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid stimulating hormone (TSH) were used. Finally, the prognostic markers Ki-67, mitotic count, and p53 tumor suppressor gene positivity were added for the pathological study of the samples, according to the French five-tiered classification.
Complete and Uneventful Recovery in a Case of Lymphocytic Hypophysitis Causing a Third Nerve Palsy
Published in Neuro-Ophthalmology, 2023
Jamie M. Nord, Paras P. Shah, Rashmi Verma
The most common symptoms of LH are related to mass effect. Headache is the most reported early symptom, which 60% of patients report on diagnosis.11 These headaches may be severe, generalised, retro-orbital, or bitemporal. Forty percent of patients have visual field deficits due to optic chiasm compression.3 Patients also describe symptoms of adenohypophyseal hypofunction including fatigue, lethargy, loss of libido, amenorrhoea, dizziness, nausea and vomiting. ACTH is the most common hormone deficiency, occurring in 65% of patients.12 Thirty percent of patients experience hyperprolactinaemia, which can result in amenorrhoea or galactorrhoea in women and sexual dysfunction in men.13 However, given that most women present in pregnancy or the postpartum period, these symptoms are difficult to identify. Some patients also have symptoms of neurohypophysis involvement from diabetes insipidus.1,14
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
On examination of sections stained with haematoxylin and eosin under a light microscope, the pituitary tissues of the control group had adenohypophysis tissue composed of normal chromophobic acidophilic and basophilic cells. We also observed normal pituicytes and neurohypophysis tissue with non-myelinated axons (Figure 1a and b, Table 2, HHS: 0.5(0-1)). In contrast, in sections obtained from the x-ray irradiation group, we observed many necrotic chromophobic and chromophilic cells in adenohypophysis tissue accompanied by diffuse vacuolar accumulation in the cytoplasm. Similarly, we determined necrotic pituicytes with diffuse vacuolar content in the neurohypophysis. In addition, there were extensive oedematous areas and vascular congestions caused by necrotic cells in both the adenohypophysis and neurohypophysis (Figure 1c and d, Table 2, HHS: 6(6-7)). On examination of the pituitary tissue sections of the dexmedetomidine treatment group under a light microscope, we observed necrotic chromophobic, chromophilic cells in adenohypophysis tissue and cells with fewer necrotic pituicytes in neurohypophysis tissue. We also determined a reduction in oedematous areas and vascular congestion in both the adenohypophysis and neurohypophysis (Figure 1e and f, Table 2, HHS: 2(1-2)).
Related Knowledge Centers
- Anterior Pituitary
- Axon
- Oxytocin
- Paraventricular Nucleus of Hypothalamus
- Supraoptic Nucleus
- Endocrine System
- Vasopressin
- Pituitary Gland
- Hypothalamus
- Neurohypophysial Hormone
- Paraventricular Nucleus of Hypothalamus