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T T Turner

Publications and source records attributed to T T Turner.

At least 55 records · Page 3Linked to original sources
PubMed1989

On the proluminal movement of 3H-androgens across the rat epididymal epithelium.

3H-Androgens in rat epididymal interstitium have previously been shown to move into the epididymal lumen against a concentration gradient. This is true especially in the caput epididymidis. The present investigation used the technique of in vivo epididymal perifusion and tubule micropuncture to demonstrate that the proluminal movement of 3H-androgens is subject to competitive inhibition (unlabeled testosterone in the perifusion fluid at 10 times and 100 times the concentration of 3H-testosterone significantly reduced proluminal movement of isotope) and is not energy-dependent (1 mM 2,4-dinitrophenol in perifusion fluid did not reduce the proluminal movement of isotope). Additionally, dry-mount autoradiography demonstrated high intraluminal concentrations of isotope relative to interstitial concentrations after caput tubule incubation in 3H-dihydrotestosterone (3H-DHT), and showed that the high intraluminal concentrations of isotope were not dependent on the presence of spermatozoa, i.e. proluminal movement of 3H-androgens was not due to binding to intraluminal spermatozoa. Isolation of caput epididymidal sperm on filters followed by 3H-DHT binding experiments also failed to demonstrate the presence of specific binding of this androgen to spermatozoa. Finally, it was confirmed that electrophoresed epididymal lumen fluid contains a single 3H-DHT binding peak that is at its highest concentration in the caput epididymal fluid. These data are consistent with the conclusion that intraluminal androgen-binding protein is an important factor in transepithelial androgen movement.

Androgens↗
PubMed1989

Proluminal movement of 3H-androgen across the epididymal epithelium in the rat after hypophysectomy and gonadotropin supplementation.

The effects of hypophysectomy and gonadotropin replacement on transepithelial movement of 3H-androgen in the rat epididymis were examined by in vivo microperifusion of 3H-testosterone followed by in vivo micropuncture to obtain peritubular and intraluminal fluid. In the caput epididymidis of normal rats, intraluminal 3H-androgen concentrations were approximately 300% of those in the interstitial space. In contrast, proluminal movement of 3H-androgen into rat caput epididymal tubules was significantly decreased 10 days after hypophysectomy. 3H-Testosterone movement across the caput epididymal epithelium was completely returned to normal by supplementation with 24 micrograms/day follicle-stimulating hormone (FSH) or 24 micrograms/day luteinizing hormone (LH). However, neither 0.12 micrograms/day FSH nor 250 micrograms/day prolactin returned proluminal androgen movement to normal. It is speculated that epididymal uptake of peritubular testosterone is mediated by androgen-binding protein, which is known to be secreted by Sertoli cells after stimulation by FSH or testosterone.

Animals↗
PubMed1988

Effects of cytochalasin D on the integrity of the Sertoli cell (blood-testis) barrier.

Ectoplasmic specializations (ES) containing packed actin microfilaments are associated with the numerous parallel rows of occluding junctions which form the Sertoli cell (blood-testis) barrier. To determine if ES regulate the structure of the occluding junctions and/or barrier permeability, we experimentally disrupted ES microfilaments in vivo with intratesticularly injected cytochalasin D (CD). Electron microscopic observations of seminiferous tubules from CD-treated (150-500 microM CD; 0.5-12 hr) animals indicated that ES was absent from regions where the Sertoli cell barrier is located. Seminiferous epithelial sheets from uninjected or vehicle-injected animals (1 DMSO: 1 saline) stained with NBD-phallacidin demonstrated the presence of patterned ES actin surrounding the basolateral regions of adjacent Sertoli cells. After exposure to CD, epithelial sheets exhibited increasingly patchy fluorescence indicating progressive F-actin disruption. Freeze-fracture replicas of CD-injected testes revealed numerous focal alterations in the region of occluding junctions which included disorganization of the parallel arrangement of junctional rows, the presence of free-ending rows, clustering of intramembranous particles (IMPs) between rows, reduction in the number of rows, and loss of IMPs on both the P-face and E-face. Tracer experiments, following CD exposure, were conducted to test the integrity of occluding junctions: lanthanum hydroxide, dextrose, or filipin was added, in separate experiments, to the fixative during perfusion-fixation. In another study, serum containing an antibody against adluminal germ cells was injected intratesticularly, and frozen sections were processed for immunofluorescence study. A final study consisted of simultaneous intratesticular infusions of CD and radiolabelled inulin with subsequent intraluminal and peritubular fluid sampling. In animals which were injected with CD, lanthanum was found to enter the adluminal compartment; fixative made hypertonic by addition of dextrose caused germ cells within the adluminal compartment to shrink and produce exaggerated intercellular spaces; filipin-cholesterol perturbations were present between some Sertoli cell junctional rows and on spermatid plasma membranes; and IgG was detected within the adluminal compartment of many seminiferous tubules. None of these adluminal manifestations was noted in control animals or those which received vehicle. Quantitatively, in the in vivo micropuncture experiments, significantly more radiolabelled inulin entered the lumen of seminiferous tubules from CD-treated animals than from those exposed to vehicle.(ABSTRACT TRUNCATED AT 400 WORDS)

Actin Cytoskeleton↗
PubMed1988

Transepithelial movement of 3H-androgen in seminiferous and epididymal tubules: a study using in vivo micropuncture and in vivo microperifusion.

In vivo micropuncture and a new system of in vivo microperifusion were used to examine the movement of 3H-androgen from blood to lumen and from interstitum to lumen in the rat testis and epididymis. Movement of 3H-androgen into the seminiferous tubule lumen was restricted, with intraluminal isotope concentrations plateauing at approximately 15% of extratubular isotope concentrations whether the 3H-androgen originated in the vascular or interstitial compartments. In the caput epididymidis, intraluminal 3H-androgen plateaued at approximately 35% of serum concentrations, but when 3H-androgens were presented directed to the basal aspect of the caput epididymidal epithelium, 3H-androgen was transported into the lumen against a concentration gradient. Intraluminal isotope concentrations were greater than 200% of those in the epididymal interstitial compartment. Similar results were found for the cauda epididymids. Factors controlling the proluminal movement of 3H-androgens in the rat testis and epididymis were therefore fundamentally different.

Androgens↗
PubMed1987

Influence of proteins in rat cauda epididymidal lumen fluid on cauda sperm motility.

Rat cauda epididymidal spermatozoa are kept quiescent in the cauda lumen by a protein fraction termed "immobilin", but it has not been shown whether or not this activity is unique to the immobilin fraction. Cauda fluid was subjected to gel filtration chromatography and the eluents contributing to three peaks of absorbance at A280 were pooled, and reconstituted at equivalent concentrations. Their relative viscoelasticity and their effects on sperm motility were determined. Peak 1 (P1), containing proteins greater than 400 kd, retained the greatest sperm-immobilizing activity but P2 and P3 also had sperm-immobilizing activity related to their viscoelasticity. P1 and an immobilin fraction obtained by ultracentrifugation of rat cauda fluid were generally similar in their sperm-immobilizing activity, viscoelasticity index, electrophoretic patterns, and binding characteristics to Concanavalin A; perm-immobilizing factor obtained by gel filtration chromatography and the immobilin fraction obtained by centrifugation are believed to be the same products. Further, it was shown that intraluminal intraluminal testicular fluids did not inhibit cauda sperm motility even at epididymal-like protein concentrations; thus, it is believed that the sperm-immobilizing factor(s) is of epididymal, not testicular, origin.

Animals↗
PubMed1987

On unilateral testicular and epididymal torsion: no effect on the contralateral testis.

It is often stated that unilateral testicular torsion results in damage to the contralateral testis; however, there are a growing number of experimental and clinical papers which suggest this is not so. Conflicting results from experimental studies confuse the issue and may be due, among other things, to some specifics of the experimental model. In the present paper, we have examined bilateral rat testes 30 and 60 days after 720 degrees torsion to determine 1) the effect of unilateral testicular torsion with and without the inclusion of epididymal torsion, 2) the effect of relatively chronic torsion (24 hr., 10 day) versus relatively acute torsion (two hr., four hr.), and 3) the effect of establishing the model using scrotal surgery versus using an abdominal approach. Bilateral testicular histology, testis wt. (gm.), cauda epididymal sperm concentrations (sp./ml.), and cauda sperm motility scores (0-4) were examined. Ipsilateral testicular torsion or testicular plus epididymal torsion of two hr. or four hr. duration significantly reduced (p less than .05) ipsilateral testis weights, sperm concentrations, and motility scores, and disrupted normal tissue histology. Contralateral testicles were not altered. Epididymal ischemia alone produced no significant ipsilateral or contralateral effects. Chronic torsion (one day, 10 days) also destroyed ipsilateral testis function without altering the contralateral testicles. The occult cryptorchidism associated with the scrotal approach to establishing the torsion model had no effect on contralateral testicles. In no group, using either Lewis rats or Sprague-Dawley rats, were contralateral testicles altered by unilateral testicular torsion. These results plus recent clinical reports indicate that contralateral testicular damage due to ipsilateral torsion is hardly a proven phenomenon, let alone a significant factor contributing to male infertility.

Animals↗
PubMed1987

Experimental varicocele does not affect the blood-testis barrier, epididymal electrolyte concentrations, or testicular blood gas concentrations.

It has been previously shown that 30-day experimental left varicocele (ELV) in adult rats produces a bilateral increase in testicular blood flow and temperature, as well as a concomitant decrease in epididymal sperm count and motility. In the present study, adult male rats with induced ELV were subjected to a variety of studies to determine the mechanism by which unilateral ELV causes a bilateral testicular response. The results demonstrate that ELV does not alter the blood-testis barrier (BTB) to 3H-inulin (MW 5000), it being largely excluded from entry into the tubule lumen in both control and ELV animals. Neither left nor right cauda epididymidal temperature was altered by ELV. Intraepididymal Na+ and K+ concentrations in the left caput epididymidis were 81.3 +/- 3.8 mEq/l and 26.3 +/- 1.5 mEq/l, respectively. From the cauda epididymidis, these values were 25.0 +/- 2.2 mEq/l and 46.8 +/- 1.0 mEq/l, respectively. These values were similar on the right side and in the left and right epididymis of ELV animals. Left testis arterial pH was 7.3 +/- 0.1, and PO2 and PCO2 were 116.0 +/- 6.4 mm of mercury and 44.3 +/- 3.2 mm of mercury, respectively. Left testicular venous values were 7.3 +/- 0.1 (pH), and 52.6 +/- 2.2 mm of mercury and 49.9 +/- 2.0 mm of mercury. These values were similar for right control testicles and left and right testicles of ELV animals. These results indicate that the mechanism by which unilateral ELV produces a bilateral change in testicular or epididymal function is not by altering the BTB, epididymal temperature or electrolyte concentrations, or testicular blood gas concentrations.

Animals↗
PubMed1987

Inhibition of testicular testosterone biosynthesis following experimental varicocele in rats.

In an attempt to determine whether defective testicular testosterone (T) biosynthesis may be associated with a varicocele, an experimental study was performed in adult rats whereby a unilateral left varicocele was surgically created. At 2, 4, 8, and 12 wk following the creation of the varicocele, intratesticular T as well as the activities of three (17 alpha-hydroxylase, 17,20-desmolase, and 17 beta-hydroxysteroid dehydrogenase) of the five enzymes in the delta 4 pathway of testicular T biosynthesis were measured. Intratesticular T (ng/g testis +/- SEM) in the left testis decreased significantly from 121 +/- 21 in the control group to 59 +/- 8 in the two-wk varicocele group (p less than 0.01), and remained significantly suppressed throughout the experimental period. The T concentrations in the right testis paralleled those in the left in both the control and varicocele animals. At 2 wk following the creation of the varicocele, the activity (nmol/min/testis +/- SEM) of the 17,20-desmolase enzyme decreased significantly, from 115 +/- 8 in the left testis of control rats to 87 +/- 6 in the left testis of the varicocele animals (p less than 0.025), and remained low throughout the 12 weeks of the study. The activity of the 17 alpha-hydroxylase enzyme was significantly decreased at the 8th and 12th weeks of the study, while the 17 beta-hydroxysteroid dehydrogenase activity did not show any significant change during the study period. The enzyme activities in the right testis paralleled those in the left testis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effects of varicocele after unilateral orchiectomy and sympathectomy.

An experimental varicocele was created in the adult rat by partial ligation of the left renal vein. There was a significant bilateral elevation of both testicular blood flow and temperature in the varicocele animals (p less than 0.01). Mean testicular blood flow for control and varicocele animals was 29.6 +/- 1.0 and 39.8 +/- 2.0 ml./min./100 gm. tissue, while mean testicular temperature was 34.4 +/- 0.1 and 35.3 +/- 0.2C, respectively. A left orchiectomy was combined with a left varicocele to determine if the left testis is essential for the right testicular response to a varicocele. Elevation of right testicular blood flow was not altered by left orchiectomy (p less than 0.05); however, right testicular temperature was no longer significantly increased. Mean right testicular blood flow and temperature for this group was 39.0 +/- 1.5 ml./min./100 gm. tissue and 34.2 +/- 0.15C, respectively. A left sympathectomy was combined with a left varicocele to ascertain if the right testicular response to the left varicocele was mediated through a neural pathway. A significant bilateral increase in testicular blood flow was noted with a left sympathectomy alone, and thereby masked the ability to evaluate the right testicular response to the simultaneous left sympathectomy and varicocele. Elevation of right testicular blood flow in response to the left varicocele is independent of the presence of a left testis and any immune response it may stimulate. The role of the sympathetic nervous system as a mediator of the bilateral varicocele effect remains undetermined.

Animals↗
PubMed1985

Cauda epididymal sperm motility: a comparison among five species.

Rat spermatozoa are immotile in the cauda epididymidis and are kept quiescent by a protein which increases viscoelasticity of cauda luminal fluid. How species-specific this phenomenon is, is unknown. In the present study, the motility of cauda epididymal spermatozoa of rats, hamsters, guinea pigs, rabbits and humans have been investigated. Sperm motility was observed in undiluted cauda sperm samples and in samples diluted with physiological diluents with or without Ca++, among others. Hamster sperm were studied in further detail to determine if the motility inhibiting factor in hamster cauda lumen fluid had characteristics similar to those previously described in the rat. Cauda fluid protein concentrations and apparent viscoelasticity were also determined and related to cauda sperm motility in all species. The results demonstrated that all species studied except rabbits have immotile sperm in their native cauda fluid and that additional Ca++ is not a factor in the initiation of motility. Cauda sperm immotility is not always related to fluid viscosity, however, so other as yet unknown mechanisms must be called upon in some species. The vigorous motility of rabbit spermatozoa in their native fluid implies that a fundamental difference exists in the relationship between epididymis and spermatozoa in rabbits from that observed in other species.

Animals↗
PubMed1985

Content of K+ and Na+ in seminiferous tubule and rete testis fluids from Sertoli cell-enriched testes.

Seminiferous tubules of rats exposed to x-irradiation before birth were subjected to micropuncture in situ at 50 days of age to obtain samples of fluid 4 h after ligation of efferent ducts. The concentrations of cations in this fluid were: potassium, 39.7 +/- 1.2 mM, and sodium, 136.3 +/- 1.2 mM (means and standard errors, n = 5). Histologic examination revealed that germ cells constitute less than 1% of the cell population within the seminiferous tubules of these rats; the remaining cells were all Sertoli cells. Sertoli cells showed efflux of 86Rb+ with t1/2 of approximately 11 min and an active ATPase in plasma membranes. These activities were similar to those of Sertoli cells from normal rats. Germ cells from normal rats showed less rapid efflux of 86Rb+ (t1/2 greater than 60 min) and less active Na+/K+ ATPase in plasma membranes. It is concluded that Sertoli cells are responsible for the high concentration of potassium in seminiferous tubule fluid and that plasma membranes of these cells contain an active K+ pump that is not inhibited by ouabain (1 mM).

Animals↗
PubMed1985

Androgens in male rat reproductive tract fluids: hypophysectomy and steroid replacement.

The control of androgen concentrations in the intraluminal fluids of the male reproductive tract is not well understood. The present experiments were performed to determine the effects of hypophysectomy, hypophysectomy plus testosterone (T), and hypophysectomy plus pregnenolone treatment on intraluminal androgen concentrations in the adult rat testis and epididymis. T and 5 alpha-dihydrotestosterone (DHT) concentrations were determined in the vascular, interstitial, and intraluminal compartments of the epididymis. Testicular and epididymal morphology also were examined under light microscopy. Hypophysectomy of at least 5 days duration significantly reduced T and DHT concentrations in serum, tissues, and intraluminal fluids of the reproductive tract. T replacement for 14 days, which produced peripheral T concentrations of 5 ng/ml, did not support intraluminal androgen concentrations in the seminiferous tubules equivalent to controls; rete testis androgen concentrations were similar to controls, however. Pregnenolone administration at 2 mg X rat-1 X day-1 for 14 days did not maintain spermatogenesis nor intraluminal T concentrations in the seminiferous tubules equivalent to controls; however, a low level of spermatogenesis continued when intraluminal and tissue androgen concentrations were maintained at 10-20% of controls by either the testosterone and pregnenolone treatments.

Androgens↗
PubMed1984

Alloplastic spermatocele: diffusion across the allograft material and survival of spermatozoa in vitro and in vivo.

Alloplastic spermatoceles have not proved to be a very successful method for acquiring fertile spermatozoa from patients with obstructive azoospermia. Many basic aspects of spermatocele function have apparently not yet been considered; therefore, we performed experiments to determine the motility survival of rat spermatozoa in spermatoceles in vivo and in vitro, and of human spermatozoa in spermatoceles in vitro. Also, net diffusion of Na+, K+, 3H-H2O, 3H-inulin and 3H-polyethyleneglycol from alloplastic spermatoceles was determined in vitro. Spermatoceles were constructed from expanded polytetrafluoroethylene. In general, neither rat nor human spermatozoa motility survived 24 hr. incubation in alloplastic spermatoceles in vitro or in vivo. Na+ and K+ diffused from alloplastic spermatoceles, demonstrating that specific intraluminal electrolyte concentrations cannot be maintained in polytetrafluorethylene spermatoceles. 3H-H2O diffused freely across the spermatocele wall, demonstrating that fluids can enter or exit the spermatocele lumen and potentially effect sperm survival. 3H-inulin (m.w. 5000) and 3H-polyethyleneglycol (m.w. 4000) were largely retained in the spermatocele lumen over the 3-day experimental period. It is recommended that other basic aspects of spermatocele design be worked out experimentally before perhaps premature designs are installed in human patients.

Animals↗
PubMed1984

Varicocele: reversal of the testicular blood flow and temperature effects by varicocele repair.

An experimental left varicocele was created in the adult rat by partial ligation of the left renal vein. A varicocele repair was performed by high ligation of the internal spermatic vein. Testicular blood flow and temperature changes were measured in control and sham animals, animals 30 days after establishment of varicocele and animals 30 days after varicocele repair. There was a statistically significant (p less than or equal to 0.01) bilateral elevation of testicular blood flow and temperature in the varicocele group compared to control and sham groups. Varicocele repair returned these blood flow and temperature values to normal. Average testicular blood flow for control, varicocele, sham varicocele and varicocele repair animals were 29.6 +/- 1, 39.8 +/- 2, 30.7 +/- 1 and 29.8 +/- 1 ml. per min. per 100 gm. tissue, respectively. Testicular temperatures averaged 34.4 +/- 0.1, 35.3 +/- 0.2, 34.4 +/- 0.1 and 34.5 +/- 0.1 degrees C, respectively. It is possible that the elevation in blood flow is associated with the elevation of intratesticular temperature, which is known to impair spermatogenesis. The data support a relationship between the varicocele and potential testicular damage.

Animals↗
PubMed1984

On the androgen microenvironment of maturing spermatozoa.

Adult anesthetized male rats were submitted to in vivo micropuncture of the seminiferous and epididymal tubules and reproductive tract vasculature to obtain fluids for analysis of testosterone, 5 alpha-dihydrotestosterone, and androgen-binding protein (ABP). Androgen and ABP concentrations were determined by RIA. The highest concentrations of testosterone (73.14 +/- 5.12 ng/ml) were in testicular interstitial fluid. A significant downhill concentration gradient exists between testosterone concentrations in testicular interstitial fluid and seminiferous tubule fluid (50.24 +/- 2.26 ng/ml); another significant decrease occurs between seminiferous tubule fluid and rete testis fluid (17.85 +/- 2.11 ng/ml). 5 alpha-Dihydrotestosterone concentrations were highest in intraluminal caput epididymidal fluids (58.73 +/- 6.48 ng/ml) as were ABP concentrations (33.30 +/- 2.40 mu leq/microliter). Intraluminal sperm concentrations were also determined, and from these data, fluid reabsorption by the efferent ducts and epididymal tubules were calculated. Eighty-nine percent of the fluid leaving the testis is reabsorbed between the rete testis and caput epididymidis, and 96% is reabsorbed between rete and cauda. It was calculated that large losses of androgen and ABP also occur from the lumen of the excurrent duct system. These losses may be due to metabolism, diffusion from the lumen, or uptake by cells.

Androgen-Binding Protein↗
PubMed1984

Resorption versus secretion in the rat epididymis.

Micropuncture samples were taken from the rete testis, caput epididymidis and cauda epididymidis of anaesthetized adult rats and assayed for total protein, sodium and potassium concentrations. Intraluminal sperm concentrations were determined and used to calculate the amount of fluid resorbed from the efferent duct and epididymal lumen. It was demonstrated that large amounts of protein (30.2 mg/ml cauda volume) and sodium (241.8 mequiv./l) and smaller amounts of potassium (19.4 mequiv./l) are resorbed from the rat epididymal lumen between the caput and corpus epididymidis. This occurs despite increases in intraluminal concentrations of protein (from 22 to 28 mg/ml) and potassium (from 16 to 50 mequiv./l). Resorption is an important aspect of epididymal control of the intraluminal environment.

Absorption↗
PubMed1983

The transepithelial movement of 3H-3-O-methyl-D-glucose in the hamster seminiferous and cauda epididymidal tubules.

Studies were performed in male hamsters to determine whether antiluminal, active glucose transport played a role in maintaining low glucose concentrations in male reproductive tract fluids. Studies of tissue uptake of 3H-3-O-methyl-D-glucose (3H-3OMG) demonstrated that after equilibrium seminiferous tissue 3H-3OMG concentrations were similar to blood plasma concentrations. Previous studies have shown that under similar circumstances seminiferous tubule lumen fluid 3H-3OMG concentrations are much lower than blood plasma concentrations. These facts suggested the possible presence of an antiluminal, active transport system for glucose in the seminiferous epithelium. In vivo perfusion of seminiferous tubules with fluids containing 3H-3OMG demonstrated an approximately 80% removal of the isotope after 1.5 hours. This movement was against a blood-lumen glucose gradient and was consistent with antiluminal active glucose transport. Increasing phloridzin concentrations in intraluminal perfusion fluid tended to be associated with decreased removal of 3H-3OMG from the lumen fluid; however, this effect was not significant; thus the evidence failed to support a hypothesis of an active antiluminal glucose pump in the seminiferous epithelium. Movement of 3H-3OMG across the cauda epididymidal epithelium was limited in both the pro- and antiluminal direction. The blood-epididymal barrier for 3H-3OMG movement appears to be much more restrictive than the blood-seminiferous tubule barrier for the same molecule.

3-O-Methylglucose↗