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Androgens and bone function
Published in Barry G. Wren, Progress in the Management of the Menopause, 2020
That estrogens are the main sex steroids for the maintenance of bone density has been suggested by the findings of osteopenia in a male with normal T and a defective ER21, and an aromatase deficiency in a male with elevated circulating T22. In these studies the men were tall (both 204 cm) with a juvenile hone age and normal or elevated T and free T levels (Table 1). The man with the E receptor mutation had a significantly reduced BMD at the lumbar spine when compared with young adults, but had borderline osteopenia when his bone density was compared with that of boys of the same biological age. The young man with aromatase deficiency22 had osteoporosis of the distal radius when compared with young adults, but in fact had BMDs of the lumbar spine and hip region well within the normal range. Interestingly, both young men studied demonstrated increases in the serum markers of bone formation, namely alkaline phosphatase, bone-specific alkaline phosphatase and osteocalcin, indicative of enhanced bone-forming activity.
Variation of sex differentiation
Published in Joseph S. Sanfilippo, Eduardo Lara-Torre, Veronica Gomez-Lobo, Sanfilippo's Textbook of Pediatric and Adolescent GynecologySecond Edition, 2019
Anne-Marie Amies Oelschlager, Margarett Shnorhavorian
Aromatase converts testosterone to estradiol and androstenedione to estrone. Aromatase deficiency is an autosomal recessive condition and results in virilization of the 46,XX infant due to reduced placental ability to convert precursors to estrogens, with high levels of placental testosterone and androstenedione. Adolescents may present with hypergonadotropic hypogonadism and progressive virilization.11 Additionally, the mother may experience virilization during pregnancy.
Introduction to Human Cytochrome P450 Superfamily
Published in Shufeng Zhou, Cytochrome P450 2D6, 2018
Given the important role of CYPs in the metabolism of a series of endogenous compounds, CYP-mediated diseases comprise those caused by aberrant steroidogenesis, defects in fatty acid, cholesterol and bile acid pathways, vitamin D dysregulation, and retinoid (as well as putative eicosanoid) dysregulation during fertilization, implantation, embryogenesis, fetogenesis, and neonatal development (Nebert et al. 2013; Rowland and Mangoni 2014). These diseases include the following: 21-Hydroxylase deficiencyAlzheimer’s diseaseAromatase deficiencyAromatase excess syndromeAutoimmune Addison diseaseBietti’s crystalline dystrophyCerebrotendinous xanthomatosisCongenital adrenal hyperplasia attributed to 11β-hydroxylase deficiencyCorticosterone methyloxidase deficiencyEarly-onset glaucomaEssential hypertensionFamilial hyperaldosteronismGhosal hematodiaphyseal dysplasiaHereditary spastic paraplegia type 5Multiple sclerosisPeters anomalyVitamin D–dependent rickets
A rare case of Seymour fracture in an adult with non-fused growth plates
Published in Case Reports in Plastic Surgery and Hand Surgery, 2021
The underlying reason for this discrepancy between actual and bone age was better determined by growth plate anatomy and factors affecting fusion. Growth plate in children has three zones (resting, proliferative, hypertrophic) located between epiphysis and metaphysis. Each zone has chondrocytes differentiation at a variable pace particularly during pubertal growth spurt. Other processes including extracellular matrix secretion, osteoblast differentiation and vascular invasion also occur. The exact mechanism of epiphyseal fusion and growth plate arrest at the end of puberty is still not completely understood. The delay in fusion is noted in those with oestrogen deficiency and precocious puberty [5]. Male patients with oestrogen resistance and aromatase deficiency showed incomplete epiphyseal closure. It highlights that oestrogen plays a role in stimulating growth plate maturation and epiphyseal fusion via a poorly understood mechanism. One of the important cellular factors is the differentiation and ageing of chondrocytes in the growth plate. Various paracrine factors play a role in chondrocyte differentiation, vascularisation and osteoblast ossification [7]. Various medical reasons may contribute to the delay in the fusion of growth plates till adulthood. We highlight the need to engage in a well-informed discussion about this diagnosis with the patient and refer to endocrinology team for further investigations accordingly.
Molecular diagnostics of disorders of sexual development: an Indian survey and systems biology perspective
Published in Systems Biology in Reproductive Medicine, 2019
MR Nagaraja, Satya Prakash Gubbala, C. R. Wilma Delphine Silvia, Ramars Amanchy
AR and SRD5A2 mutations were the commonly reported amongst cases of 46,XY DSD from Indian clinics. Mutations in AR, SRD5A2, MAMLD1, WT1, and MAP3K1 often presented hypospadias as one of the or as a soul dysmorphic feature. Deficits in testis-promoting, differentiation, and/or maintenance genes (such as SRY, WT1, DHH, NR5A1, and DMRT1) led to distinct dysmorphic phenotypes causing GD. SRY mutations were reported in patients diagnosed with gonadoblastoma, infertility, and hypogonadism. STAR and DAX1 mutations led to congenital lipoid adrenal hyperplasia and adrenal hypoplasia, respectively. In addition, a rare case of 46,XX DSD harbored CYP19A1 missense mutation that led to aromatase deficiency was reported.
Estrogen – serotonin interaction and its implication on insulin resistance
Published in Alexandria Journal of Medicine, 2019
Estrogen is a female sex steroid hormone that plays important roles in both reproductive and non-reproductive functions [22]. E2, as a predominant form of estrogen, is synthesis by P450 aromatase (Aro) enzyme from testosterone (T) [11,22]. Early ontogeny of Aro is detected as early as embryonic day 9 (E9) with the optimal peak at E13-14 in mouse brain [23]. Similarly, high expression of brain aromatase (AroB) is detected at 48 hours post-fertilizations (hpf) in zebrafish, indicating that locally produced E2 in the brain is necessary for brain development and functions [24]. Expression of Aro in the brain is mainly localized in the amygdala, preoptic area, and hypothalamus [25,26]. While Aro is detected in the neuron and glial cells in mammals [27], fish Aro (brain type, AroB) only detected in glial cells, which later able to differentiate into neurons [28]. Previously, it is reported that healthy male treated with anastrozole (aromatase inhibitor, AI) for 6 weeks with 2 weeks washout periods exhibited a reduction of peripheral insulin sensitivity [29]. Indeed, homeostasis model assessment-insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) confirmed that the administration of E2 improved insulin sensitivity in male patients with aromatase deficiency [30]. However, it seems that the low level of E2 is not the only factor in developing IR, rather than the ratio between E2 and T [30]. Similarly, mice lacking Aro (ArKO) displayed glucose intolerance and IR [31] and E2 enhanced insulin sensitivity by stimulating phosphorylation levels of protein kinase B (Akt), downstream signaling pathways of insulin [32].