Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

ABSTRACTContextExperimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS.ObjectiveTo analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function.Design and SettingProspective study. University Settings.Patients51 testicular scans, 17 testes from 10 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions.Main OutcomesCEUS kinetic parameters.ResultsCEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.008), mean transit time (MTT, p = 0.008), time to peak (TTP, p < 0.001), and washout time (Tout 50%, p = 0.008) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels.ConclusionsTesticular venous blood flow is altered in KS and independently predicts T peripheral release.

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Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab605 ◽

2021 ◽

Author(s):

Francesco Carlomagno ◽

Carlotta Pozza ◽

Marta Tenuta ◽

Riccardo Pofi ◽

Luigi Tarani ◽

...

Keyword(s):

Blood Flow ◽

Klinefelter Syndrome ◽

Mean Transit Time ◽

Venous Blood ◽

Experimental Studies ◽

Principal Component ◽

Endocrine Function ◽

Venous Blood Flow ◽

Testicular Blood Flow

Abstract Context Experimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS. Objective To analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function. Design and Setting Prospective study. University Setting. Patients 68 testicular scans, 34 testes from 19 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions. Main Outcomes. CEUS kinetic parameters. Results CEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.018), mean transit time (MTT, p = 0.035), time to peak (TTP, p < 0.001), and washout time (Tout 50%, p = 0.004) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels. Conclusions Testicular venous blood flow is altered in KS and independently predicts T peripheral release.

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Arterio-Venous Branchial Blood Flow in the Atlantic Cod Gadus Morhua

Journal of Experimental Biology ◽

10.1242/jeb.165.1.73 ◽

1992 ◽

Vol 165 (1) ◽

pp. 73-84 ◽

Cited By ~ 2

Author(s):

LENA SUNDIN ◽

STEFAN NILSSON

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Atlantic Cod ◽

Vascular System ◽

Venous Blood ◽

Venous Blood Flow ◽

Venous Flow ◽

Flow Measurements ◽

Vasomotor Function

We have estimated the branchial venous blood flow in the Atlantic cod by direct single-crystal Doppler blood flow measurements in vivo. In the undisturbed animal, this flow amounts to 1.7 ml min−1 kg−1, which corresponds to about 8 % of the cardiac output. Studies of both an isolated perfused gill apparatus in situ and simultaneous measurements of cardiac output and branchial venous flow in vivo were made to assess the effects of some putative vasoregulatory substances. Adrenaline dilates the arterio-arterial pathway and constricts the arterio-venous pathway, thus decreasing branchial venous drainage. 5-Hydroxytryptamine (5-HT), in contrast, produced marked vasoconstriction in the arterio-arterial pathway of the branchial vasculature, increasing the branchial venous blood flow. Cholecystokinin-8 (CCK-8) and caerulein produced similar cardiovascular effects, with marked constriction of both arterio-arterial and arterio-venous pathways. The study demonstrates the ability of the vascular system of the gills to regulate the distribution of branchial blood flow, and summarizes the vasomotor effects of some substances with possible vasomotor function in the cod gills.

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Compensatory mechanisms in response to an elevated hepatic oxygen consumption in chronically ethanol-fed rats

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1985.248.5.g507 ◽

1985 ◽

Vol 248 (5) ◽

pp. G507-G511 ◽

Cited By ~ 1

Author(s):

J. E. Bredfeldt ◽

E. M. Riley ◽

R. J. Groszmann

Keyword(s):

Blood Flow ◽

Oxygen Consumption ◽

Hepatic Artery ◽

Oxygen Delivery ◽

Venous Blood ◽

Venous Blood Flow ◽

Compensatory Mechanisms ◽

Hepatic Oxygen Consumption ◽

Portal Venous Blood

During conditions that elevate hepatic oxygen consumption (VLO2), oxygen delivery, or oxygen extraction may also increase, acting as compensatory mechanisms. VLO2 was quantitated by an in vivo method in chronically ethanol-fed rats to establish whether VLO2 was increased and what compensatory mechanisms might ensue. VLO2 was increased 45% (0.32 +/- 0.02 ml O2 X min-1 X 100 g body wt-1; P less than 0.001) in rats chronically fed ethanol for 8 wk, while VLO2 (0.28 +/- 0.04; P = NS) was not increased in chronically ethanol-fed rats withdrawn from ethanol 20 h before study compared with control rats (0.22 +/- 0.01). Oxygen delivery was increased 31% (P less than 0.05) in ethanol-fed rats and adequately compensated for the increased VLO2. Hepatic artery blood flow did not increase in ethanol-fed rats, indicating a lack of hepatic artery vasodilation in response to the elevated VLO2. As a result, a greater percentage of oxygen delivery was supplied via portal venous blood flow that has a reduced oxygen content. These observations might suggest that ethanol-fed rats may have a decreased reserve for maintaining an adequate oxygen supply to the liver and may be at an increased liability for developing hepatic hypoxia if oxygen delivery and/or extraction were compromised.

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Limitations Imposed by Testicular Blood Flow on the Function of Leydig Cells in Rats in vivo

Australian Journal of Biological Sciences ◽

10.1071/bi9830285 ◽

1983 ◽

Vol 36 (3) ◽

pp. 285 ◽

Cited By ~ 20

Author(s):

BP Setchell ◽

KAA Galil

Keyword(s):

Blood Flow ◽

Leydig Cells ◽

Venous Blood ◽

Testis Weight ◽

Single Exposure ◽

Efferent Duct ◽

Efferent Ducts ◽

Duct Ligation ◽

Testicular Blood Flow

Testis blood flow per testis closely follows testis weight in rats made aspermatogenic by a single exposure of the testis to 43�C for 30 min or 500 rad (5 Gy) of irradiation from a caesium source, or following ligation of the efferent ducts. Aspermatogenesis following these treatments was associated with only minor changes in the concentrations of testosterone in peripheral blood before stimulation with human chorionic gonadotrophin (hCG), and a reduced responsiveness to hCG when testis weight had fallen after heating. The concentrations of testosterone in testicular venous blood was normal or above normal during aspermatogenesis resulting from heat or irradiation, and only slightly reduced following efferent duct ligation.

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