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Purpose: The diagnosis of primary hyperparathyroidism (PHPT) and chronic hypoparathyroidism (HypoPT) is still challenging, especially in patients asymptomatic or with non-classical phenotypes and for physicians not skilled in calcium-phosphorous (Ca–P) disorders. The serum calcium/phosphorous (Ca/P) ratio has been proposed as accurate index to identify PHPT, while it has never been tested in HypoPT. The aim of this study is to investigate the diagnostic power of the serum Ca/P ratio in the diagnosis of primary parathyroid dysfunctions (both PHPT and HypoPT) in a large series of data. Methods: A multicentric, retrospective, cross-sectional study (ClinicalTrials.gov: NCT03747029) was carried out including 432 PHPT patients and 217 HypoPT patients compared with 389 controls. Serum Ca, P, creatinine, parathyroid hormone and 25OH-vitamin D were collected. Serum Ca and P were expressed in mmol/L. Ca/P diagnostic performance was evaluated by receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy. Results: The Ca/P ratio was significantly higher in PHPT and lower in HypoPT patients than controls (p < 0.0001). At ROC curve analysis, the Ca/P ratio above 2.55 was defined to identify PHPT patients (sensitivity 85.7%, specificity 85.3%) and below 1.78 to identify HypoPT patients (sensitivity 88.2%, specificity 87.9%). Conclusions: The Ca/P ratio is a highly accurate index to identify PHPT when Ca/P is above 2.55 and HypoPT when it is below 1.78. These results demonstrate the reliability of this index to rule in/out primary parathyroid dysfunctions and remark the importance of measuring serum P in clinical practice.

The serum calcium/phosphorus (Ca/P) ratio is an accurate tool to differentiate patients with primary hyperparathyroidism (PHPT) from healthy subjects. However, other disorders of the Ca–P metabolism might impair the Ca/P ratio, such as hypophosphatemia (HypoP) not PHPT related. The aim of this study is to examine the diagnostic value of Ca/P ratio in the diagnosis of PHPT and HypoP not PHPT related. Single-center, retrospective, case–control study, including 150 patients with PHPT and 306 patients with HypoP, compared with 150 controls. HypoP patients were enrolled among HIV-infected patients by selecting those with Fanconi-like syndrome due to antiretroviral treatment. Parameters which were measured were serum Ca, P, parathyroid hormone (PTH), 25-OH vitamin D, albumin and creatinine). The Ca/P ratio was significantly higher in PHPT and HypoP patients, compared to controls (p

Primary hyperparathyroidism (PHPT) diagnosis is challenging and is based on serum calcium (Ca) and parathyroid hormone (PTH). Because serum Ca and phosphorous (P) are inversely related in PHPT, we investigated the diagnostic value of the serum Ca/P ratio in the diagnosis of PHPT. We report a single-center, case-controlled, retrospective study including 97 patients with documented PHPT and compared them with those of 96 controls (C). The main outcome measures were: serum PTH, 25-OH vitamin D, Ca, P, albumin, and creatinine. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the serum Ca/P ratio were calculated. The results were verified using an independent, anonymous set of data extracted from a laboratory database containing over 900 million entries. A total of 35 (36.1%) PHPT patients had normocalcemic PHPT (NCHPT). Ca and PTH were significantly higher in PHPT than in C (p

The effect of self-monitoring of blood glucose (SMBG) on glycemic control with regard to non-insulin-treated Type 2 diabetes mellitus (NIT-Type 2 DM) is still a controversial topic. Against this backdrop, we sought to compare the effect of a continuous short-term SMBG schema with as-usual treatment, based on changes in oral antidiabetic treatment in patients with poorly controlled Type 2 DM. We reviewed 492 NIT-Type 2 DM record charts, selecting 27 patients, with poor glycemic control, who were thought to self-monitor their blood glucose levels (SMBG group). We then compared them with 27 patients treated with modifying drugs or diets to achieve and maintain the glycemic target (Control Group). Haemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) were evaluated at baseline, after 3 and 6 months. HbA1c values decreased after 3 and 6 months in the SMBG group (P < 0.001 on both occasions) and in the control group (P < 0.05 and P < 0.01, respectively), but without a significant difference between the two groups when compared at the same time. The FPG progressively decreased in both groups, reaching a significant difference in the SMBG group after 3 months and in the control group after 6 months, and without a significant difference between the two groups. The SMBG schema used in our study could be adopted for target groups before proceeding to the next therapeutic enhancement drug step, representing a useful tool that can help diabetic patients in raising awareness of and treating their disease.

Purpose: In order to understand how thyroid abnormalities emerge over time in adults, we evaluated incidence of thyroid diseases in healthy subjects, after almost 6 years from a previous negative ultrasound. Methods: Anamnestic and physical data were collected. Ultrasound neck evaluation was performed by an experienced endocrinologist, recording detailed thyroid and nodules characteristics. Nodules were classified according to American Thyroid Association classification for prediction of cancer risk. Serum samples were collected for subsequent evaluations (TSH, free thyroid hormones, calcitonin, anti-thyroid antibodies). Anamnestic, clinical, sonographic, and serological characteristics were analyzed with logistic regression analysis for subjects with nodules vs. those without. Results: One hundred and eleven subjects were enrolled (43M, 68F). Half of them developed nodules, mainly smaller than 1 cm and without suspicious characteristics. Ninety-seven percent were euthyroid. Only 4% had serological diagnosis of thyroiditis. Incidence of thyroid diseases was higher in women, especially nulliparous. Comparing clinical characteristics of subjects with and without nodules, the only statistically significant difference concerned thyroid volume adjusted for body weight or surface (p < 0.05), but not residual volume excluding nodules. Multivariate logistic regression analysis showed that female gender, higher BMI-adjusted thyroid volume and residual thyroid volume excluding nodules, nulliparity, age, and fT3 increase the risk of developing nodules. Conclusions: These results demonstrate that adult thyroid tissue undergoes changes that are already detectable by US after almost 6 years. Half of the enrolled subjects developed de novo nodules or colloid cysts of poor clinical relevance.

Background: The beneficial effects of vitamin D, together with the high prevalence of vitamin D deficiency, have led to an expanding use of vitamin D analogues. While inappropriate consumption is a recognized cause of harm, the determination of doses at which vitamin D becomes toxic remains elusive. Case presentation: A 56-year woman was admitted to our Hospital following a 3-week history of nausea, vomiting, and muscle weakness. The patient had been assuming a very high dose of cholecalciferol for 20 months (cumulative 78,000,000UI, mean daily 130,000UI), as indicated by a non-- conventional protocol for multiple sclerosis. Before starting vitamin D integration, serum calcium and phosphorus levels were normal, while 25OH-vitamin D levels were very low (12.25 nmol/L). On admission, hypercalcemia (3.23 mmol/L) and acute kidney injury (eGFR 20 mL/min) were detected, associated with high concentrations of 25OH-vitamin D (920 nmol/L), confirming the suspicion of vitamin D intoxication. Vitamin D integration was stopped, and in a week, hypercalcemia normalized. It took about 6 months for renal function and 18 months for vitamin D values to go back to normal. Conclusions: This case confirms that vitamin D intoxication is possible, albeit with a high dose. The doses used in clinical practice are far lower than these and, therefore, intoxication rarely occurs even in those individuals whose baseline vitamin D serum levels have never been assessed. Repeated measurements of vitamin D are not necessary for patients under standard integrative therapy. However, patients and clinicians should be aware of the potential dangers of vitamin D overdose.

Summary A 74-year-old man was referred to the Endocrinology Unit because of multinodular goiter. The dominant nodule (1.7 × 1.9 × 2.4 cm), at the medium-superior third of the left lobe, was inhomogeneously hypoechoic, with irregular margins, macrocalcifications and intranodular vascularization. Fine-needle aspiration biopsy (FNAB) was performed. The cytological diagnosis was TIR 2, benign, according to the 2013 Italian thyroid cytology classification system. Moderately high serum calcitonin (s-Ct) (61.5 pg/mL, n.r. 0–7.5) and normal CEA were detected. The Ct level in FNAB wash-out fluid (Ct-FNAB) was 1450 pg/mL. Based on s-Ct and Ct-FNAB levels, patient underwent total thyroidectomy. Macroscopically, a dominant circumscribed nodule of 2 ecm was described; the histological and immunohistochemical features identified medullary thyroid carcinoma (MTC) with paraganglioma (PG)-like pattern positive for Ct, CEA and chromogranin and negative for S-100 sustentacular cells (SC). Moreover, papillary carcinoma of 3 mm in the right lobe was also associated. No areas of hyperaccumulation of the tracer were documented at Ga68 PET/CT. No RET-proto-oncogene mutations were found. Post-surgery s-Ct levels were within normal range (4 pg/mL). Two years after thyroidectomy, the patient is still disease-free. We reported a case of sporadic and rare variant of MTC: this is the ninth described case of PG-like MTC. In this case, cytologically benign, the clinical suspicion arose from high Ct values at FNAB wash-out fluid. Even if clinical behavior of this variant seems indolent, additional studies are necessary to understand prognoses and predictive factors. Learning points: Several unusual histological variants of medullary thyroid carcinoma (MTC) have been described such as spindle cell, giant cell, clear cell, melanotic, squamous, angiosarcoma-like variants; even rarer is the paraganglioma (PG)-like pattern. We here describe a case of medullary PG-like thyroid carcinoma in a 74-year-old man. This is a rare histological variant of MTC hardly diagnosed by cytology, since immunohistochemical investigations are necessary. Measurement of calcitonin both in serum and in wash-out fluid from fine-needle aspiration could be an additional tool for an early and non-invasive identification of these variants.

Purpose: Evaluation of the phenotype of primary hyperparathyroidism (PHPT), adherence to International Guidelines for parathyroidectomy (PTx), and rate of surgical cure. Method: From January 2014–January 2016, we performed a prospective, multicenter study in patients with newly diagnosed PHPT. Biochemical and instrumental data were collected at baseline and during 1-year follow-up. Results: Over the first year we enrolled 604 patients (age 61 ± 14years), mostly women (83%), referred for further evaluation and treatment advice. Five hundred sixty-six patients had sporadic PHPT (93.7%, age 63 ± 13 years), the remaining 38 (6.3%, age 41 ± 17 years) had familial PHPT. The majority of patients (59%) were asymptomatic. Surgery was advised in 281 (46.5%). Follow-up data were available in 345 patients. Eighty-seven of 158 (55.1%) symptomatic patients underwent PTx. Sixty-five (53.7%) of 121 asymptomatic patients with at least one criterion for surgery underwent PTx and 56 (46.3%) were followed without surgery. Negative parathyroid imaging studies predicted a conservative approach [symptomatic PHPT: OR 18.0 (95% CI 4.2–81.0) P < 0.001; asymptomatic PHPT: OR 10.8, (95% CI 3.1–37.15) P < 0.001). PTx was also performed in 16 of 66 (25.7%) asymptomatic patients without surgical criteria. Young age, serum calcium concentration, 24h urinary calcium, positive parathyroid imaging (either ultrasound or MIBI scan positive in 75% vs. 16.7%, P = 0.001) were predictors of parathyroid surgery. Almost all (94%) of patients were cured by PTx. Conclusions: Italian endocrinologists do not follow guidelines for the management of PHPT. Negative parathyroid imaging studies are strong predictors of a non-surgical approach. PTx is successful in almost all patients.

Summary Spontaneous or fine-needle aspiration (FNAB)-induced remission of primary hyperparathyroidism (PHPT) may occur, especially for cystic lesions. However, the disease generally relapses over a short time period. We present a case of PHPT due to an enlarged hyperfunctioning parathyroid that underwent long-term (almost 9 years) clinical and ultrasonographic remission after the disappearance of the lesion following ultrasound (US)-assisted FNAB. A 67-year-old woman with PHPT underwent biochemical and US examinations that confirmed the diagnosis and showed a lesion suggestive for parathyroid adenoma or hyperplasia. US-FNAB of the lesion confirmed its parathyroid nature by means of elevated levels of parathyroid hormone within the needle washing fluid. At the second visit, the patient referred slight neck swelling that resolved spontaneously in the days after the US-FNAB. At subsequent follow-up, the enlarged parathyroid was not found; it was visible neither with US nor with magnetic resonance imaging. Biochemical remission persists after 9 years. This is the first reported case of cure of PHPT after US-FNAB performed on a hyperfunctioning parathyroid resulting in its complete disappearance over a period of 9 years of negative biochemical and ultrasonographic follow-up. Learning points: Spontaneous or fine-needle aspiration-induced remission of primary hyperparathyroidism can occur. Both circumstances may present disease relapse over a variable time period, but definite remission is also possible even though long-term periodic follow-up should be performed. Parathyroid damage should be ruled out in case of neck symptomatology after parathyroid fine-needle aspiration or spontaneous symptomatology in patients with history of primary hyperparathyroidism.

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, with a steadily increasing incidence in the last few decades worldwide. The predisposition to developing this carcinoma by the heterozygous state of rs2910164 within the precursor of the miR-146a has been reported, but recently not confirmed. Interestingly, on the same chromosome, almost 50 kb separate the pre-miR-146a from the pituitary tumor-transforming gene 1 (PTTG1), a proto-oncogene involved in several tumors, including thyroid cancers. In this study, we analyzed, using a case–control design, the genetic association between PTC and the genomic region encompassing pre-miR-146a rs2910164 and PTTG1 rs1862391 and rs2910202. We enrolled 307 affected patients and 206 healthy controls. The possible presence of thyroid nodules in controls was excluded by ultrasonography. All the cases were submitted to single-nucleotide polymorphism (SNP) genotyping of pre-miR-146a and PTTG1, and risk association analyses were carried out. The genotypic and allelic frequencies of pre-miR-146a rs2910164 were not statistically different in the patients and controls, and this SNP was not in linkage disequilibrium with the investigated PTTG1 SNPs. Consistently, meta-analyses, the first including all the affected cases published to date, did not confirm the previously reported association of the heterozygous CG genotype with PTC. The PTTG1 SNPs exhibited the same allelic frequency in the patients and controls and were not associated with the disease. In conclusion, in a well-selected Italian population, neither pre-miR-146a rs2910164 nor PTTG1 rs1862391 and rs2910202 were found to be associated with the risk of developing PTC.

ObjectiveGH secretion is impaired in lipodystrophic human immunodeficiency virus (HIV) patients and inversely related to lipodystrophy-related fat redistribution in men. Less is known about the underlying mechanisms involved in reduced GH secretion in HIV-infected women.DesignA case–control, cross-sectional study comparing GH/IGF1 status, body composition, and metabolic parameters in 92 nonobese women with HIV-related lipodystrophy and 63 healthy controls matched for age, ethnicity, sex, and body mass index (BMI).MethodsGH, IGF1, IGF binding protein 3 (IGFBP3), GH after GHRH plus arginine (GHRH+Arg), several metabolic variables, and body composition were evaluated.ResultsGH response to GHRH+Arg was lower in HIV-infected females than in controls. Using a cutoff of peak GH ≤7.5 μg/l, 20.6% of HIV-infected females demonstrated reduced peak GH response after GHRH+Arg. In contrast, none of the control subjects demonstrated a peak GH response ≤7.5 μg/l. Bone mineral density (BMD), quality of life, IGF1, and IGFBP3 were lowest in the HIV-infected females with a GH peak ≤7.5 μg/l. BMI was the main predictive factor of GH peak in stepwise multiregression analysis followed by age, with a less significant effect of visceral fat in the HIV-infected females.ConclusionsThis study establishes that i) GH response to GHRH+Arg is lower in lipoatrophic HIV-infected women than in healthy matched controls, ii) BMI more than visceral adipose tissue or trunk fat influences GH peak in this population, and iii) HIV-infected women with a GH peak below or equal to 7.5 μg/l demonstrate reduced IGF1, IGFBP3, BMD, and quality of life.

Androgens act on erythropoiesis, but the relative role of testosterone (T) and estradiol (E(2)) on erythropoietic parameters in men is a poorly investigated issue. In order to evaluate separately the effects on erythropoiesis of high-dose T administration alone and of physiological dose of E(2) administration alone two adult men with aromatase deficiency were assessed before and during each treatment. Blood cell count, hemoglobin (Hb), hematocrit (Hct), erythrocyte mean cell volume (MCV), erythrocyte mean corpuscular hemoglobin (MCH), erythrocyte mean corpuscular hemoglobin concentration (MCHC), serum ferritin, iron and total iron-binding capacity (TIBC), serum erythropoietin, serum total testosterone and estradiol were evaluated. Hb, Hct and red cell count rose during testosterone treatment, consistently with the increase in circulating testosterone, but failed to increase during estradiol treatment. A decrease in Hb, Hct and red cell count was recorded in one of the two subjects during estradiol treatment, with a concomitant decrease in serum testosterone. Circulating T alone is capable of and sufficient to influence erythropoiesis, especially at supraphysiological dosage, while circulating E(2) have not the same effect on erythropoietic parameters, suggesting the hypothesis that the erythropoietic changes induced by androgens are not mediated via its aromatization to estrogens.

By investigating the relationship between serum testosterone, estradiol, and bone mineral density (BMD) in a large cohort of HIV-infected men, estradiol was associated with BMD, relative estrogen deficiency being involved in bone loss in men with hypogonadism, in addition to all HIV-related factors. Increased aromatization in adipose tissue does not counteract HIV-related bone loss. The purpose of this study is to evaluate the relationship between serum testosterone, estradiol, and BMD in a large cohort of HIV-infected men. We investigated biochemical, hormonal parameters, and BMD in 1204 HIV-infected men (age 45.64 ± 7.33 years) participating in a cross-sectional, observational study. Among other parameters, the main outcome measures were serum total testosterone and estradiol, gonadotropins, 25-hydroxyvitamin D [25(OH)D], parathormone (PTH), calcium, phosphorous, femoral, and lumbar BMD. In men with HIV, the prevalence of osteoporosis and osteopenia is 15.1 and 63.2 % with 25(OH)D insufficiency being very common (60.1 %). After age adjustment, BMD is positively associated with estradiol, but not testosterone, at linear (p

Recently, a remarkable progress has been made in our understanding about the role of sex steroids in male physiology. In this paper, we consider the clinical aspects of congenital estrogen deficiency — notably, estrogen resistance and aromatase deficiency — in men and we discuss both well-established and supposed estrogen roles in the human male reproductive function. These topics include the role of estrogens in the control of gonadotropin secretion, in male fertility determination and psychosexual behavior. Briefly, estrogens play a pivotal role in the control of serum gonadotropin concentrations in the human male. Furthermore, a possible role of estrogens on both human male fertility and sexuality has also been suggested by recent studies, even though the available data are far from being conclusive. Conversely, for what concern fertility and sexual behavior, a well-established effect of estrogens has been provided by recent studies on male rodents, which show impaired sexual behavior and fertility as a consequence of estrogen defect.

Erectile dysfunction (ED) is common among elderly men and patients suffering from chronic diseases, the latter probably including also HIV infection. No studies, however, compared the prevalence of ED in HIV-infected and HIV-uninfected individuals using the international index of erectile function (IIEF-15).The aim of this study is to compare ED prevalence in young to middle-aged men with and without HIV infection using the IIEF-15 questionnaire.We conducted a cross-sectional, observational, controlled study on 444 HIV-infected men and 71 HIV-uninfected men.The IIEF-15 questionnaire was used to assess ED. A cutoff score of ≤25 of the erectile domain was used to diagnose ED. Serum testosterone, demographic, and anthropometric (weight, height, and body mass index [BMI]) characteristics were obtained from all participants. Statistics included the T-test, the Fisher's test, univariable and multivariable logistic regression, and univariate and multivariate Spearman's correlation analysis.The HIV-uninfected group was significantly younger than the HIV-infected group and presented a higher BMI (P 0.001). The prevalence of mild, moderate, and severe ED was higher in HIV-infected men than in HIV-uninfected men of all decades of age. In univariate analysis, HIV infection was associated with ED (odds ratio [OR] = 34.19, P 0.001). In multivariable logistic regression analysis, HIV infection remained the strongest predictors of ED (OR = 42.26, P 0.001) followed by hypogonadism, after adjusting for age and BMI.This study demonstrates a clear association between ED and HIV infection, after adjusting for age and BMI. Other than HIV infection, hypogonadism was associated with ED. In addition, the prevalence of ED was higher in HIV-infected men than in HIV-uninfected men, in all decades of age. The early onset of ED in HIV-infected men could be considered a peculiar clinical hallmark of HIV and confirms precocious aging in these patients. ED should be of concern to clinicians when managing HIV-infected men even if the latter are young or middle aged.

Cushing's syndrome may remain unrecognized among patients referred for metabolic syndrome; thus, a proactive screening has been suggested in certain patient populations with features of the disorder. However, conflicting data have been reported on the prevalence of Cushing's syndrome in patients with type 2 diabetes.Our aim was to evaluate the prevalence of unsuspected Cushing's syndrome among outpatients with type 2 diabetes.This was a cross-sectional prospective study in 24 diabetes clinics across Italy.Between June 2006 and April 2008, 813 patients with known type 2 diabetes without clinically overt hypercortisolism were evaluated. Follow-up of the study was closed in September 2010. Patients were not selected for characteristics conferring a higher pretest probability of hypercortisolism. Patients underwent a first screening step with the 1-mg overnight dexamethasone suppression test.Forty patients failed to suppress serum cortisol less than 5.0 μg/dl (138 nmol/liter) and underwent a standard 2-d, 2-mg dexamethasone suppression test, after which six patients (0.6% of the overall series) failed to suppress cortisol less than 1.8 μg/dl (50 nmol/liter), receiving a definitive diagnosis of Cushing's syndrome that was adrenal dependent in five patients. Four patients were cured, being able to discontinue, or reduce, the glucose-lowering agents.The present data do not support widespread screening of patients with type 2 diabetes for Cushing's syndrome; however, the disorder is less rare than previously thought when considering epidemiology of type 2 diabetes. Our results support a case-finding approach in patients with uncontrolled diabetes and hypertension despite appropriate treatment.

Aims The role of sex steroids in glucose and insulin metabolism in men remains unclear. To investigate the effects of sex steroids and oestrogen on insulin sensitivity in men, we studied two male adults with aromatase deficiency (subject 1 and subject 2). Methods The effects of transdermal oestradiol (tE2) treatment at different dosages on insulin sensitivity were studied before tE2 treatment (phase 1), and after 6 months (phase 2) and 12 months of tE2 treatment (phase 3) by means of homeostasis model assessment—insulin resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI), insulin tolerance test (ITT), and oral glucose tolerance test (OGTT). The latter was performed only in subject 1, as subject 2 suffered from Type 2 diabetes. Results The restoration of normal serum oestradiol led to improved insulin sensitivity, as shown by changes in HOMA-IR and QUICKI. The ITT provided evidence of improved insulin sensitivity during tE2 treatment. Insulin secretion after OGTT was reduced during tE2 treatment in subject 1. After 12 months of tE2 treatment, insulin sensitivity was improved compared with in phases 1 and 2. Conclusions The study suggests a direct involvement of oestrogens in insulin sensitivity, and supports a possible role of oestradiol : testosterone ratio, which may be as influencial as the separate actions of each sex steroid on glucose homeostasis.

Male age-related bone loss is caused, at least in part, by hypogonadism that occurs with advancing age. The study of the effects of sex steroids on bone physiology in men has recently highlighted the central role of estrogens on bone pathophysiology. This review focuses on particular aspects of bone physiology and pathophysiology in aging men, noting both the similarities to and the differences from female counterparts. In particular, the role of sex steroids on bone sexual dimorphism in health and disease has been analyzed.

To study the effects of sildenafil on human sleep-related erections according to the state of androgenization, we evaluated the effects of sildenafil on sleep-related erections in hypogonadal men before and during testosterone replacement treatment and in control subjects. We enrolled 24 hypogonadal men and 24 healthy men as a control group. All hypogonadal subjects had very low testosterone levels (

The role of estrogen on male reproductive function has become clearer in the last decade. During these years the study of the effect of testosterone, estrogen or an aromatase inhibitor in hypogonadal men provided a first evidence of the effects of estrogens in the regulation of gonadotropin secretion. At the same time, the development of a line of transgenic male mice lacking estrogen receptor α, estrogen receptor β or aromatase gene provided further evidence about the role of estrogens not only in the regulation of gonadotropin secretion, but also on the effects of estrogens on testicular function and development. A confirmation of these actions of estrogens came from the observation of naturally occurring mutations of the estrogen receptor and of the aromatase gene in human males. Based on these data it has been demonstrated that estrogens are major regulators of gonadotropin secretion acting both at pituitary and hypotalamic level. The presence in the human reproductive structures of estrogen receptor α, estrogen receptor β and the aromatase enzyme indicates the existence of receptor α, estrogen receptor β or aromatase estrogen actions at this level. Anyway, the precise role of estrogens in testicular development and function and on the regulation of human spermatogenesis has not yet been precisely clarified.

The report focuses on the role of estrogens in human male, dealing with two human models of congenital estrogen deficiency: estrogen resistance and aromatase deficiency. Similarities and differences of clinical phenotypes of these models are described and progresses of estrogen treatment of aromatase-deficient men are reported. Finally, the putative use of estrogen in men and the use of aromatase inhibitors and antiestrogen for male disorders are discussed.