Comparative rates of formation, in vivo, of 16-androstenes, testosterone and androstenedione in boar testis

1984 ◽  
Vol 103 (2) ◽  
pp. 179-186 ◽  
Author(s):  
E. L. Hurden ◽  
D. B. Gower ◽  
F. A. Harrison
Keyword(s):  
Binding Sites ◽  
Venous Blood ◽  
Peripheral Circulation ◽  
Total Radioactivity ◽  
Venous Blood Flow ◽  
Large White ◽  
The Third ◽  
Very High ◽  
Venous Plasma

ABSTRACT Three mature Large White boars were anaesthetized and received [7(n)-3H]pregnenolone by continuous infusion into right and left spermatic arteries for up to 180 min. Spermatic venous blood flow was measured by separate timed collections of completely diverted outflow from each testis and blood not sampled was returned to the peripheral circulation. The total radioactivity in plasma from each testis increased markedly during the first 60 min of infusion to reach a plateau from 80 to 180 min. Radiolabelling of 5α-androst-16-en-3-one, 5α-androst-16-en-3β-ol and -3α-ol showed similar patterns with ratios of mean radioactivity of 5:3:1 respectively between 80 and 180 min. In comparison, the amounts of tritiated 4,16-androstadien-3-one formed were very small. The radiolabelling of testosterone and 4-androstenedione occurred more rapidly than that of the 16-androstenes and reached maxima by 30 min. However the amounts were only one-fifth (testosterone) and one-tenth (4-androstenedione) those of the combined quantities of tritiated 16-androstenes. Addition of human chorionic gonadotrophin (hCG) to the infusate to one testis in each animal (so that 5000 i.u. hCG were delivered in 15–20 min) produced no change in the outputs of radiolabelled steroids although radioimmunoassay of spermatic venous plasma in samples from the third experiment showed a transient increase in the concentration of 4-androstene-3,17-dione during the hCG infusion. It is suggested the lack of response to hCG could be produced by saturation and down regulation of binding sites by the very high local concentrations of hCG. J. Endocr. (1984) 103, 179–186

SECRETION OF PROGESTERONE DURING GESTATION IN THE RAT

1978 ◽  
Vol 79 (2) ◽  
pp. 179-190 ◽  
Author(s):  
MRINAL K. SANYAL
Keyword(s):  
Abdominal Aorta ◽  
Primary Source ◽  
Solvent System ◽  
Peripheral Circulation ◽  
Systemic Circulation ◽  
Maternal Circulation ◽  
Secondary Importance ◽  
System Hexane ◽  
Venous Plasma

The concentrations of progesterone and 5α-pregnane-3,20-dione in ovarian and uterine venous plasma and in the systemic circulation were measured during gestation in the rat. The steroids were quantified by radioimmunoassay after separation on silicic acid microcolumns with the solvent system hexane: ethyl acetate (5: 2, v/v). The concentration of progesterone in the systemic circulation was highest on days 3–4 and 13–17 of pregnancy; throughout gestation, the concentration of 5α-pregnane-3,20-dione was low in relation to that of progesterone and showed no marked changes as gestation proceeded. The level of progesterone in ovarian venous effluent was 10–20 times higher than that in the uterine vein and 20–50 times greater than that in the systemic circulation. The rate of secretion of progesterone by the ovary was highest during days 13–17 of gestation and ovariectomy during this period markedly reduced the levels of progesterone in the peripheral circulation. The concentration of progesterone in the uterine venous effluent was raised compared with the concentration in plasma from the abdominal aorta, especially on days 7 and 9 of pregnancy. These results suggest that, in vivo, the rat placenta synthesizes small amounts of progesterone and secretes it into the maternal circulation. The ovary is the primary source of progesterone during pregnancy and the placental contribution is of secondary importance. Although 4-ene-5α-reductase enzyme(s) is present in the ovary and placenta, significant quantities of the reduced progestin 5α-pregnane-3,20-dione are not secreted into the systemic circulation during gestation in the rat.

Effects of PACAP1–27 on the canine endocrine pancreas in vivo: interaction with cholinergic mechanism

2003 ◽  
Vol 81 (7) ◽  
pp. 720-729 ◽  
Author(s):  
Nobuharu Yamaguchi ◽  
Tamar Rita Minassian ◽  
Sanae Yamaguchi
Keyword(s):  
Endocrine Pancreas ◽  
Venous Blood ◽  
Insulin Response ◽  
Glucagon Secretion ◽  
Venous Blood Flow ◽  
Dependent Manner ◽  
Cholinergic Mechanism ◽  
Insulin And Glucagon Secretion ◽  
Anesthetized Dogs

The aim of the present study was to characterize the effects of pituitary adenylate cyclase activating polypeptide (PACAP) on the endocrine pancreas in anesthetized dogs. PACAP1–27 and a PACAP receptor (PAC1) blocker, PACAP6–27, were locally administered to the pancreas. PACAP1–27 (0.005–5 μg) increased basal insulin and glucagon secretion in a dose-dependent manner. PACAP6–27 (200 μg) blocked the glucagon response to PACAP1–27 (0.5 μg) by about 80%, while the insulin response remained unchanged. With a higher dose of PACAP6–27 (500 μg), both responses to PACAP1–27 were inhibited by more than 80%. In the presence of atropine with an equivalent dose (128.2 μg) of PACAP6–27 (500 μg) on a molar basis, the insulin response to PACAP1–27 was diminished by about 20%, while the glucagon response was enhanced by about 80%. The PACAP1–27-induced increase in pancreatic venous blood flow was blocked by PACAP6–27 but not by atropine. The study suggests that the endocrine secretagogue effect of PACAP1–27 is primarily mediated by the PAC1 receptor, and that PACAP1–27 may interact with muscarinic receptor function in PACAP-induced insulin and glucagon secretion in the canine pancreas in vivo.Key words: atropine, PACAP, PAC1, muscarinic, interaction.

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

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

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.

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

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 &lt; 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.

PGF2 alpha and PGE2 binding to rat myometrium during gestation, parturition, and postpartum

1990 ◽  
Vol 258 (5) ◽  
pp. E740-E747
Author(s):  
M. Molnar ◽  
F. Hertelendy
Keyword(s):  
Placebo Group ◽  
Binding Sites ◽  
Binding Capacity ◽  
Specific Binding ◽  
Time Dependent ◽  
Scatchard Analysis ◽  
Plasma Progesterone ◽  
High Affinity ◽  
The Third ◽  
Venous Plasma

The specific binding of prostaglandins (PG) F2 alpha and E2 was studied in a rat myometrial membrane-enriched fraction during the latter part of gestation and parturition, as well as in the postpartal period. Tritiated PGE2 and PGF2 alpha binding was specific, saturable, time dependent, and directly proportional to the amount of membrane protein. Scatchard analysis indicated the presence of high-affinity (Kd2) and low-affinity (Kd2) binding sites for both PGs. The affinity of both binding sites for PGF2 alpha and the apparent Kd2 for PGE2 remained essentially the same throughout gestation and post-partially and were similar to nonpregnant rats. The apparent Kd1 of PGE2, however, increased by 10-fold from day 21 of gestation to 1 day postpartum. Although the maximal binding capacity of the high-affinity (Bmax1) and low-affinity (Bmax2) binding sites of PGF2 alpha showed a nonsignificant increase compared with prepartum values, reaching maximal values 12-24 h postpartum, those of PGE2 showed a significant increase on the third day after delivery. The concentration of prostanoids in uterine venous plasma and amniotic fluid increased significantly with approaching parturition, whereas plasma progesterone decreased, raising the estradiol-progesterone ratio 25-fold. After unilateral fetectomy, the binding sites for PGF2 alpha and PGE2 increased significantly compared with the contralateral pregnant horns. Administration of the PG synthetase inhibitor, indomethacin, also increased two- to threefold both PGF2 alpha and PGE2 binding compared with the placebo group, whereas intrauterine administration of PGF2 alpha and PGE2 significantly reduced it.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Studies on the metabolism of 5α-androst-16-en-3-one in boar testis in vivo

1974 ◽  
Vol 144 (2) ◽  
pp. 347-352 ◽  
Author(s):  
Y. A. Saat ◽  
D. B. Gower ◽  
F. A. Harrison ◽  
R. B. Heap
Keyword(s):  
Venous Blood ◽  
Specific Radioactivity ◽  
Testicular Tissue ◽  
Constant Rate ◽  
Sexually Mature ◽  
Venous Plasma

1. [5α-3H]5α-Androst-16-en-3-one (5α-androstenone) was infused at a constant rate for 180min into the spermatic artery of a sexually mature boar. Samples of spermatic-venous blood were collected at 1min intervals for the first 10min of the infusion and thereafter at 15min intervals for the first hour, then at 64, 125, 155 and 172min. After infusion, the testis was removed and immediately cooled to −196°C. 2. From both the testicular tissue and the spermatic-venous plasma, endogenous and3H-labelled androst-16-enes were isolated, characterized and quantitatively determined and their specific radioactivity was calculated. 3. The specific radioactivities of 5α-androstenore, 5α-androst-16-en-3α-ol and 5α-androst-16-en-3β-ol (an-α and an-β) in testicular tissue were different from those in the spermatic-venous plasma, suggesting that these compounds may be present in more than one compartment of the testis and differentially secreted into the spermatic-venous blood. 4. The ratios of the specific radioactivities of an-α and an-β to their respective sulphate conjugates in the testicular tissue were less than the ratios of the same compounds in the spermatic-venous plasma. 5. The patterns of secretion of these labelled compounds in the spermatic-venous blood during the period of infusion were demonstrated. 6. The urine that accumulated during the infusion was analysed and found to contain3H-labelled an-β, conjugated as both glucuronide and sulphate, the specific radioactivities of which were determined. Little or no androst-16-enes occurred as free steroids. 7. The presence of an-β glucuronide in the urine is discussed.

scholarly journals Heterogeneity of the Human Corticotropin-Releasing Factor-Binding Protein

1997 ◽  
Vol 82 (5) ◽  
pp. 1566-1571 ◽  
Author(s):  
R. J. Woods ◽  
C. F. Kemp ◽  
J. David ◽  
P. J. Lowry
Keyword(s):  
Binding Protein ◽  
Affinity Purification ◽  
Peripheral Circulation ◽  
Corticotropin Releasing Factor ◽  
Amino Acid Residues ◽  
Third Trimester ◽  
Truncated Form ◽  
The Third

Abstract Human corticotropin-releasing factor (hCRF), secreted by the placenta, principally in the third trimester, is specifically bound in the peripheral circulation to a 37-kDa binding protein (CRF-BP). This complex is cleared from the circulation. We postulate that the protein may be returned to the blood in a form that is immunologically altered and not well recognized by the reported RIAs. We report that a stable isoform can result from temporary denaturation of recombinant CRF-BP by 8 mol/L urea. This isoform, urea-treated binding protein, which can bind CRF, has been found to bind to an antibody raised against a synthetic peptide comprising the first 24 amino acid residues of CRF-BP, but not to a second similar N-terminal antibody, although it was closely matched in titer. Urea-treated binding protein also cross-reacts poorly in the RIA with CRF-BP. It is proposed that as a result of in vivo post-ligand binding events, isoforms may be susceptible to cleavage. After affinity purification, which involves denaturation, recombinant CRF-BP was often found to be cleaved after storage in the presence of protease inhibitors. Here we present evidence for a C-terminally truncated form of the native binding protein in the plasma of subjects suffering from rheumatoid arthritis, which may parallel the in vitro truncation.

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

1992 ◽  
Vol 165 (1) ◽  
pp. 73-84 ◽  
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.

scholarly journals Meatiness of tested gilts in three consecutive years

2019 ◽  
Vol 35 (2) ◽  
pp. 153-161
Author(s):  
Marija Gogic ◽  
Cedomir Radovic ◽  
Dragan Radojkovic ◽  
Radomir Savic ◽  
Maja Petricevic ◽  
...  
Keyword(s):  
Body Weight ◽  
Performance Test ◽  
Backfat Thickness ◽  
Back Muscle ◽  
Large White ◽  
The Third ◽  
Meat Content ◽  
The Impact ◽  
Daily Gain ◽  
Very High

In the present study, the aim was to determine the impact of the following factors: age, farm, and gilt genotype, as well as the regression impact of body weight at the end of the performance test on the following tested properties: age at the end of the test/final age (FA), lifetime daily gain (LDG), the backfat thickness measured in two places (according to the Main Breeding program for Central Serbia), the depth of the long back muscle (BM) and the estimated lean meat content/meatiness (M). The study included two farms of pigs (farm 1 and farm 2), for three consecutive years (year 1, year 2 and year 3). The number of tested heads per year was 974 (year 1), 1311 (year 2) and 757 (year 3). The tested gilts were of Swedish Landrace, Large White and Duroc breeds. The gilts originated from 97 sires, while the number of daughters per sires ranged from 10 to 100. The results show that the Duroc animals were the oldest (245 days), which had the highest values for both measures of backfat thickness, but the lowest values for meatiness. In the third study year, the lowest average values were determined for the properties of the LDG, BM and M. The female animals from the farm 1 showed less growth/gain and had lower values for the estimated meatiness. As a result of the study, it was established that all included factors had a very high statistically significant influence on the variation of the tested properties (P <0.001), only the genotype of gilts showed a high statistically significant effect on the BM property (P <0.01).

scholarly journals Studies on the biosynthesis in vivo and excretion of 16-unsaturated C19 steroids in the boar

1972 ◽  
Vol 129 (3) ◽  
pp. 657-663 ◽  
Author(s):  
Y. A. Saat ◽  
D. B. Gower ◽  
F. A. Harrison ◽  
R. B. Heap
Keyword(s):  
Venous Blood ◽  
Testicular Tissue ◽  
Transferase Activity ◽  
Left Testis ◽  
Isotope Concentration ◽  
Continuous Drainage ◽  
Extractable Fraction ◽  
Sexually Mature ◽  
Venous Plasma

1. In one experiment [7α-3H]pregnenolone was infused continuously for 12min into the left spermatic artery of a sexually mature boar and blood was collected during this period by continuous drainage from the spermatic vein. After infusion, the testis was removed and immediately cooled to −196°C. 2. From both the testicular tissue and the spermatic venous plasma, 3H-labelled 16-unsaturated C19 steroids were isolated and characterized and their radiochemical purity was established. 5α-Androst-16-en-3α- and 3β-ol occurred mainly as sulphate conjugates and to a lesser extent as free steroids. Only traces of these alcohols occurred as glucosiduronate conjugates. 5α-Androst-16-en-3-one was found in the free (ether-extractable) fraction. 3. The isotope concentration of each of the 3H-labelled 16-unsaturated C19 steroids in testicular tissue was different from that in spermatic venous plasma. 4. The ratios of tritiated 5α-androst-16-en-3α- and 3β-ol (free steroids) to their respective sulphate conjugates in the testicular tissue were less than the ratios of the same compounds in the spermatic venous plasma. The possibility that the sulphates are partially hydrolysed by testicular sulphatases before secretion is discussed. 5. In a second experiment, a continuous close-arterial infusion of [7α-3H]pregnenolone into the left testis was performed over a 200min period and all the urine that accumulated during the infusion was collected for analysis. 6. No 3H-labelled 16-unsaturated C19 steroids were detected in the urine as free steroids. Only a trace of 5α-androst-16-en-3α-ol was detected conjugated as glucosiduronate, whereas the corresponding 3β-alcohol occurred mainly as glucosiduronate and to a lesser extent as sulphate. 7. The absence of 5α-androst-16-en-3β-ol glucosiduronate in the spermatic venous blood and its presence in considerable amount in the urine may be attributed to hepatic glucuronyl transferase activity.

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