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Endocrine Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Gonadotropin-releasing hormone (GnRH) stimulates LH and FSH synthesis/secretion from gonadotrophs, regulating normal ovarian function (Figure 12.6) and testicular function (Figure 12.7).
Hormonal Regulation in the Treatment of Fibroids
Published in John C. Petrozza, Uterine Fibroids, 2020
Victoria Fitz, Steven L. Young
Given the previously described role of estrogen in promoting leiomyoma growth, investigators have targeted suppression of the hypothalamic-pituitary-ovarian axis as a potential therapy to reduce leiomyoma size and associated bulk symptoms as well as AUB-L. The first agents used to reduce estrogen production were gonadotropin releasing hormone agonists (GnRHa). These agents induce a hypoestrogenic state by downregulating GnRH receptor function in pituitary gonadotroph cells, resulting in little to no FSH stimulation of ovarian estrogen production. GnRHa treatment is effective: Leuprolide acetate treatment for 3–6 months has been found to stop AUB-L in up to 80% of women and reduce both uterine and fibroid volume by about 36%–50% compared with placebo [20,21]. Side effects of therapy with GnRHa include hot flushes and other menopausal symptoms and are observed in 60%–95% of patients treated with this medication. Long-term side effects include a marked reduction in bone density. Thus, therapy with GnRHa is primarily a short-term bridge to surgical management or menopause. It is also important to note that GnRHa can lead to fibroid degeneration, and subsequent acute hemorrhage, though incidence is likely low.
Regulation of the Pituitary Gland by Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
Gonadotrophs are found throughout the anterior pituitary, alone or in groups, often in close contact with blood capillaries [59]. They are oval in shape with prominent, often eccentrically located, nuclei. They have noticeable rough endoplasmic reticulum, well-developed Golgi complexes and many secretory granules, that stain strongly for both LH and FSH. An issue that has long been debated, but remained unsettled, is whether subpopulations of gonadotrophs are monohormonal, i.e., produce only LH or FSH. Neither number nor morphology of the gonadotrophs is constant, but change with physiologic conditions. Castration, for example, induces a 2- to 3-fold increase in the number of gonadotrophs, presumably due the removal of negative feedback by gonadal hormones and increased cell number. It also results in the appearance of “castration cells,” hypertrophied gonadotrophs characterized by dilation of the endoplasmic reticulum and the presence of large vacuoles.
Subclinical hemorrhagic nonfunctionning pituitary adenoma: pituitary gland function status, endoscopic endonasal transsphenoidal surgery, and outcomes
Published in British Journal of Neurosurgery, 2023
Ming Wang, Yugang Jiang, Yang Cai, Huixuan Wu, Yong Peng
The following tests were used for assessing the pituitary hormonal status on admission in all patients: serum levels of thyroid-stimulating hormone (TSH) and free thyroxine for the thyrotroph axis; morning plasma adrenocorticotropic hormone (ACTH) and serum cortisol levels for the corticotroph axis; serum levels of prolactin (PRL) for hyperprolactinemia, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone or estradiol for the gonadotroph axis; growth hormone (GH), insulin-like growth factor 1 (IGF-1) for the somatotroph axis. For a better assessment of the pituitary functions, some patients underwent a pituitary stimulation testing, including ACTH stimulation test for the corticotroph axis; Gonadotropin-releasing hormone stimulation tests for the gonadotroph axis; insulin hypoglycemia tests or arginine-loading tests for the somatotroph axis. The diagnoses of pituitary function pre- and postoperative were made by endocrinologists. Patients’ preoperatively pituitary dysfunction were categorized according to each identified pituitary hormonal abnormality, including hypoadrenalism, hypothyroidism, hypogonadism, ‘stalk compression’ hyperprolactinemia (non-prolactinoma), and diabetes insipidus (DI). Diabetes insipidus was diagnosed on the basis of urine specific gravity 1.005 and urine volume was great than 200 mL/h for at least three consecutive hours. If there were three or more kinds of hormonal deficiency, the condition was classified as panhypopituitarism.
Post-operative vision loss: analysis of 587 patients undergoing endoscopic surgery for pituitary macroadenoma
Published in British Journal of Neurosurgery, 2022
John W. Rutland, Jonathan T. Dullea, Eric K. Oermann, Rui Feng, Dillan F. Villavisanis, Shivee Gilja, William Shuman, Travis Lander, Satish Govindaraj, Alfred M. C. Iloreta, James Chelnis, Kalmon Post, Joshua B. Bederson, Raj K. Shrivastava
A 45-year-old, right-handed male presented to the senior author’s institution with a 1-month history of blurry vision (R > L), acuity loss (R > L), fatigue, and decreased libido. An ophthalmological examination showed corrected visual acuities of 20/70 (OS) and 20/200 (OD), and dense bitemporal hemianopsia (R > L). Neuroophthalmological exam included optical coherence tomography (OCT), which revealed bilateral retinal nerve fibre layer (RNFL) thinning (OS: 70 μm, OD: 69 μm). An MRI scan revealed a 30.5 cm3 macroadenoma with suprasellar extension and compression of the optic chiasm and left optic nerve. The patient underwent endoscopic transsphenoidal surgery with the use of interoperative augmented reality guidance. The sellar floor and dura were opened to expose a fibrous tumour that was adherent to the optic chiasm. The tumour was centrally debulked with an ultrasonic aspirator. The capsule edge was defined, and the diaphragm was opened to facilitate sharp dissection along the optic nerve and chiasm. There was potentially a small amount of residual unresected tumour left along the medial wall of the cavernous sinus. A resultant CSF leak was repaired with an autologous tensor fascia lata graft. The surgery was completed without complication. Total surgical time was ∼180 min which is within the normal range expected for these surgeries at our institution. Histopathology confirmed a gonadotroph (LH Type) pituitary adenoma.
Stress and steroid interaction modulates expression of estrogen receptor alpha in the brain, pituitary, and testes of immature Gallus gallus domesticus
Published in Stress, 2021
Kalpana Baghel, Rashmi Srivastava
In avian pituitary gland, the expression of ERα was eminent in gonadotrophs, lactotrophs, and somatotrophs as estrogen directly stimulates the pituitary cells to synthesize gonadotropins hormones (LH and FSH) which stimulate the gonads to synthesize sex steroids hormones (testosterone in male and estrogen in female, respectively) (Friend et al., 1995; Li et al., 1994). Besides this, EB followed by FR also produces oxidative stress in the brain and testes by elevating corticosterone and lowering estrogen in blood which finally alters the expression of estrogen receptor alpha (ERα). The stress induces the hypersecretion of glucocorticoids from adrenal gland under the influence of ACTH. These elevated concentrations of glucocorticoids decreases the production and secretion of GnRH mediated by binding with the glucocorticoids receptors (GRs), in hypothalamic region. Subsequently, FSH and LH secretion get reduced which further inhibit gonadal steroidogenesis (Fallahsharoudi et al., 2015; Joseph & Whirledge, 2017) thereby reducing ERα expression is observed in both nucleus and cytoplasm of brain, pituitary, and testicular cells. However, EB simultaneously with FR influences the development and produces adverse effect on the male HPG-axis.