Steroid Dynamics under Steady-State Conditions

Dt, Baird; Horton, Richard; Longcope, Christopher; Jf, Tait

doi:10.1016/b978-0-12-571125-8.50017-x

Cited by 170 publications

(108 citation statements)

References 118 publications

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“…The testis directly secretes 5% of total oestrone and 15% of oestradiol. 1,12,13 Oestrone sulphate 27±29 is not secreted by the adrenal or gonads but is synthesized peripherally almost exclusively from oestradiol and oestrone in almost equal proportions. The amount of oestrone sulphate produced per day is similar to the amounts of oestrone and oestradiol (150± 300 nmol/day) but, because of its low metabolic clearance rate (less than 10% of that of oestrone and oestradiol), it has a much longer half-life (5 h) and has a serum concentration ten times that of oestrone.…”

Section: ±19mentioning

confidence: 99%

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Endocrinology of gynaecomastia

Ismail¹,

Barth²

2001

Ann Clin Biochem

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Gynaecomastia is the most common disorder of the male breast. It can occur at any age, and for this reason laboratory investigations may be requested by clinicians from many specialties. Gynaecomastia may occur transiently in neonates. It may also occur transiently during puberty, when it is common and generally benign. It must, however, be regarded as unusual in prepubertal children and all young and middle-aged men. Although iatrogenic and benign gynaecomastia are common in the elderly, further investigations may still be justi®ed since breast cancer or other neoplasm must be ruled out. Biochemical investigations, when warranted, are aimed at establishing an underlying cause. Endocrine investigations might include serum oestradiol (or oestrone if available), testosterone, luteinizing hormone, sex-hormone-binding globulin, human chorionic gonadotrophin, prolactin and thyroid function tests. In this review, the source and role of oestrogens in men, the androgen±oestrogen dynamics, the causes and clinical entities of gynaecomastia, and interpretation of laboratory tests are described.

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Section: ±19mentioning

confidence: 99%

“…Direct secretion of oestrogen by the adrenals is negligible. 12,13 Approximately 80% of oestrogen is produced extragonadally by peripheral aromatization of androgens. In contrast, testosterone is largely secreted by the testes (> 90%) with little extragonadal conversion from precursors derived from the adrenals.…”

Section: Adulthoodmentioning

confidence: 99%

Endocrinology of gynaecomastia

Ismail¹,

Barth²

2001

Ann Clin Biochem

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“…This protein was first described by Mercier et al [3] and purification has been attempted in various laboratories [l] . The physiological function of SBP is still unknown but it has been suggested that the protein may serve a role in keeping testosterone in the circulation [4,5].…”

Section: Introductionmentioning

confidence: 99%

A filter assay for the sex steroid binding protein (SBP) of human serum

1974

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“…immature rats, the ovary in females (Meijs-Roelofs et al 1973) and the adrenal gland in females and males (Baird et al 1969, Weisz & Gunsalus 1973 have been postulated for a long time as the source of E 2 ; however, it is difficult to explain the developmental change of serum E 2 levels. Recently, it was reported that the stomach is one of the extraovarian tissues synthesized and secreted by E 2 , and the E 2 levels in the portal vein are over ten times higher than those in the artery in normal conditions of adult male rats (Ueyama et al 2002, 2004, Kobayashi et al 2013.…”

Section: Discussionmentioning

confidence: 99%

Postnatal development of gastric aromatase and portal venous estradiol-17β levels in male rats

Kobayashi

Yoshida

Sun

et al. 2013

Journal of Endocrinology

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Gastric parietal cells synthesize and secrete estradiol-17b (E 2 ) into gastric veins joining the portal vein, and a large amount of gastric E 2 first binds to its receptors in the liver. However, the role of the gastric E 2 is not entirely clear during postnatal development. The objective of this study was to reveal the onset of aromatase and other steroid-synthesizing enzymes in the gastric mucosa; to determine the period of rising E 2 levels in the portal vein; and to further understand the relationship between gastric E 2 and liver estrogen receptor a (ERa). The immunoblot bands and the immunohistochemistry of gastric mucosa revealed that aromatase protein began to express itself at 20 days and then increased in the levels of aromatase protein from 20 days onward. Expression of mRNAs for gastric aromatase (Cyp19a1) and other steroid-synthesizing enzymes, 17a-Hydroxylase (Cyp17a1) and 17b-hydroxysteroid dehydrogenase (HSD17b3), also increased similar to the increment of aromatase protein. Portal venous E 2 levels were elevated after 20 days and increased remarkably between 23 and 30 days, similar to gastric aromatase mRNA levels. The E 2 level was approximately three times higher at 40 days than that at 20 days. The liver weight and Esr1 levels began to increase after 20 days and the increment was positively correlated with the change of portal venous E 2 levels. These findings suggest that some changes may occur around 20 days to regulate the gastric E 2 synthesis and secretion.

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Steroid Dynamics under Steady-State Conditions

Cited by 170 publications

References 118 publications

Endocrinology of gynaecomastia

Endocrinology of gynaecomastia

A filter assay for the sex steroid binding protein (SBP) of human serum

Postnatal development of gastric aromatase and portal venous estradiol-17β levels in male rats

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