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T T Turner

Publications and source records attributed to T T Turner.

At least 19 recordsLinked to original sources
PubMed1992

Interleukin-1 is induced in the human placenta by endotoxin and isolation procedures for trophoblasts.

Although freshly obtained placenta contains little or no interleukin-1 (IL-1) mRNA, placenta and isolated trophoblast have been reported to produce significant quantities of bioactive IL-1 in vitro. The present study was designed to determine if endotoxin, a common contaminant of culture medium, and trophoblast isolation procedures could induce IL-1 expression in the placenta. Tissue-extractable IL-1 alpha and IL-1 beta immunoreactive proteins were readily detected in fresh placental membranes, but not placental villi. As little as 10 ng/mL endotoxin were found to induce the expression of IL-1 alpha and IL-1 beta mRNA in intact placental villi cultured in vitro. Intact placenta cultured in the presence of 1.0 microgram/mL endotoxin demonstrated expression of IL-1 alpha and IL-1 beta mRNA and cumulative production and release of immunoreactive IL-1 alpha and IL-1 beta into the medium during 24 h of culture. Placenta incubated in endotoxin-free medium, however, exhibited no detectable IL-1 alpha or IL-1 beta mRNA expression and little or no release of IL-1 alpha or IL-1 beta immunoreactive protein into the medium. When trophoblast cells were freshly isolated by enzymatic digestion, followed by Percoll separation at reduced temperatures to inhibit cell activation, no IL-1 alpha or IL-1 beta mRNA expression was initially detectable. However, IL-1 alpha and IL-1 beta mRNA in isolated trophoblast cells were induced after 30 min of culture in endotoxin-free medium, with maximal induction at 4 h. These results suggest that normally the placenta produces very little, if any, IL-1, and that endotoxin and trophoblast isolation procedures induce IL-1 expression in placental tissues cultured in vitro.

Cell Separation↗
PubMed1991

Different mechanisms are responsible for 3H-androgen movement across the rat seminiferous and epididymal epithelia in vivo.

Mechanisms involved in the maintenance of the microenvironment of the seminiferous and epididymal tubules were examined in a series of experiments utilizing in vivo microperifusion, microperfusion, and micropuncture. Intraluminal 3H-androgen concentrations in seminiferous tubules increased linearly as interstitial 3H-androgen concentrations increased from 10 nM to 2,000 nM, but in caput epididymidal tubules, intraluminal 3H-androgen concentrations increased hyperbolically across the same range of peritubular 3H-androgen concentrations. Intraluminal 3H-androgen concentrations in the caput epididymidis did not rise above approximately 340 nM even if peritibular 3H-androgen concentrations exceeded 2,000 nM. Perifusion of caput tubules with 0.1 mM dinitrophenol or potassium cyanide or 100 micrograms/ml cyclohexamide significantly reduced proluminal 3H-androgen movement, but tubules perifused with control medium would not support antigrade 3H-androgen movement in the absence of native lumen fluids which contain androgen-binding protein. Antigrade proluminal 3H-androgen movement was not inhibited by competition with estradiol at ten-times 3H-androgen concentrations. Thus, energy-requiring protein synthesis is necessary for antigrade 3H-androgen movement in the caput epididymidis, but the mechanism for the interaction of intracellular protein(s) and 3H-androgen movement remains undetermined.

2,4-Dinitrophenol↗
PubMed1990

On the maintenance of male fertility in the absence of native testosterone secretion: site-directed hormonal therapy in the rat.

A method of direct percutaneous injection of testosterone (T)-laden microspheres directly into the testis was used in an attempt to achieve the maintenance of normal intratesticular T concentrations, spermatogenesis, and fertility. Rats were divided into three groups: (1) sham operated/injection controls; (2) animals receiving 250 micrograms/d gonadotropin-releasing hormone (GnRH)-antagonist; and (3) animals receiving GnRH-antagonist as in group 1 plus 20 mg T-laden microspheres/testis. Treatment periods were 45 and 90 days. Serum T, testicular interstitial fluid T, testis weights, epididymal weights, daily sperm production (sperm x 10(6)/g/d), cauda sperm motility, and fertility were assessed in all animals. Gonadotropin-releasing hormone antagonist treatment reduced serum and testicular interstitial fluid to below detectable levels at day 45 and to similar levels at day 90. Supplementation with T-laden microspheres maintained testicular interstitial fluid T at concentrations not different from controls without elevation of serum T concentrations. All other values, including fertility were suppressed by GnRH-antagonist treatment and maintained by supplementation with T-laden microspheres.

Animals↗
PubMed1990

Testicular blood flow in peripubertal and older rats with unilateral experimental varicocele and investigation into the mechanism of the bilateral response to the unilateral lesion.

Testicular and reference organ blood flows and testicular temperatures were determined in peripubertal and mature rats with and without experimental left varicocele (ELV). Testicular blood flow and temperature were significantly increased bilaterally 30 days after surgery to induce unilateral varicocele, and this was the case in both the younger and older animals. It has not previously been known that the pathophysiological effects of ELV extended to the peripubertal testis. Previous experiments have demonstrated that the left testis is not necessary for the right testicular response to varicocele. In the present paper, animals were subjected to left orchiectomy simultaneously with the surgery to induce ELV. Thirty days later, the animals were divided into those with and those without the left spermatic vein varicosity. Testicular blood flow was determined in all these animals as well as in a separate group of control and experimental varicocele animals. The group of ELV animals with left spermatic varicosity demonstrated a significant increase in contralateral testicular blood flow while the ELV group without left spermatic varicosity did not. We speculate that left venous distention is involved in the mechanism for the contralateral response to unilateral varicocele.

Animals↗
PubMed1990

Transepithelial movement of non-polar and polar compounds in male rat reproductive tubule examined by in vivo microperifusion and in vivo micropuncture.

Proluminal movement of 3H-testosterone and 3H-sucrose from peritubular to intratubular fluids of the adult rat testis and epididymis was investigated by using in vivo microperifusion and subsequent micropuncture of seminiferous tubules and caput, corpus, and cauda epididymal tubules. Tubules were perifused with Minimum Essential Medium containing 3H-testosterone or 3H-sucrose. 14C-polyethyleneglycol was included in the perifusion fluid as a marker for contamination of intraluminal fluid by interstitial fluid. Radioactivity of isotopes in perifusion and intraluminal fluids was determined at one and two hours after perifusion and the percentage of peritubular isotopes appearing in intraluminal fluid was determined. Net entry of 3H-sucrose into the seminiferous and epididymal tubules was significantly reduced. Proluminal movement of 3H-androgen across the seminiferous epithelium was also restricted. In contrast, intraluminal 3H-androgen concentrations in caput epididymal fluid were 200 to 300% of those in peritubular fluid at both one and two hours after perifusion. Similar results were found in the corpus epididymidis. 3H-androgen concentrations in cauda epididymal fluid were approximately 125% of peritubular isotope concentrations. The exact mechanism underlying this uphill proluminal movement of 3H-androgen into the rat epididymal lumen remains to be elucidated.

Androgens↗
PubMed1990

Intraluminal androgen binding protein alters 3H-androgen uptake by rat epididymal tubules in vitro.

Previous experiments have shown that androgen binding protein (ABP) and androgens exist in high concentrations in the tissue and the lumen of the rat caput epididymis. The present experiments were performed to determine whether or not intraluminal APB affects tubule net uptake of androgens. Caput epididymal tubules were dissected into 2-cm segments, subjected to microperfusion into the tubule lumen, and incubated for 2.5 h in 35 degrees C minimum essential medium (MEM) containing 2.0 ng tritiated testosterone (3H-T) per ml. 14C-polytheylene glycol [PEG] was included as a contamination marker. In the first series of experiments, caput tubules were perfused with a control, artificial perfusion (MKB) containing no ABP or fresh rat rete testis fluid (RTF), which is known to contain ABP. Tubules incubated while containing RTF took up 138% of the tritiated androgens taken up by control tubules. In the second series of experiments, tubules were perfused with fresh caput epididymal lumen content, MKB alone, MKB containing either 5.0 ng purified rat ABP/microliters or 50 ng ABP/microliters. Tubules incubated while containing perfused MKB took up only 47% of the tritiated androgens taken up by tubules containing perfused native lumen content. Increasing intraluminal ABP concentrations in the MKB medium increased 3H-androgen uptake in a stepwise fashion. Intraluminal ABP at a concentration of 50 ng/microliters was associated with a 71% return of 3H-androgen uptake towards that amount of 3H-androgen taken up by tubules perfused with native lumen content. Intraluminal ABP enhances net androgen uptake by caput epididymal tubules from their surrounding medium in vitro.

Androgen-Binding Protein↗
PubMed1989

Cytoskeletal involvement in spermiation and sperm transport.

The process of spermiation and sperm transport was studied using specific inhibitors of cytoskeletal elements. Within 12-24 hr after the intratesticular injection of taxol, a compound that acts to stabilize microtubules and inhibit microtubule-related processes, an unusually large number of microtubules was seen within the body of the Sertoli cell. At the same time, transport of elements within the seminiferous epithelium was affected. At the end of stage VI of the cycle, step 19 spermatids were maintained in the deep recesses of the Sertoli cell and not transported to the rim of the seminiferous tubule lumen. At stage VIII, residual bodies remained at, or near, the rim of the tubule and were not transported to the base of the tubule. They underwent only partial degradation at this site, indicating that there may have been two phases involved in their dissolution--one autophagic and one phagocytic, but the latter did not occur since the residual bodies were not transported to Sertoli lysosomes at the base of the tubule. The observations suggest that microtubules are involved in transport processes within the seminiferous epithelium. Within 1-12 hr after the intratesticular injection of 500 microM cytochalasin D, a compound which interferes with actin-related processes, normal appearing tubulobulbar complexes were not present. The tubular portion (distal tube) of the complex did not initiate development. It was assumed that filaments (which were identified as such using NBD-phallacidin and the S-1 fragment of myosin) played an important role in the development of this portion of the complex. Cells did not eliminate cytoplasm normally, as evidenced by an enlarged cytoplasmic droplet, further emphasizing the published role for tubulobulbar complexes in cytoplasmic elimination. Although sperm were released normally from stage VIII tubules, many remained within the tubular lumen and did not traverse the duct system. Cytochalasin did not inhibit fluid secretion by the Sertoli cell, as demonstrated by efferent duct ligation, but did alter myoid cell actin cytoskeletal organization, suggesting that myoid cell contractility is primarily responsible for transport of sperm. Overall, the observations suggest that cytoskeletal activity of the Sertoli cell is important for several aspects of the spermiation process as well as sperm transport.

Actins↗
PubMed1989

Histologic analysis of orchiopexy in a cryptorchid rabbit model.

Although there is a consensus that very early orchiopexy is advantageous, there is little experimental data to support this view. Therefore, we studied early pre-pubertal versus later pre-pubertal orchiopexy in a cryptorchid rabbit model. Male offspring were divided into four groups with six to nine rabbits in each group: 1) controls (CON); 2) shams undergoing sham operations at both three weeks and two months of life (SHAM); 3) cryptorchid on day 3 with orchiopexy at three weeks and sham operation at two months (O3W); 4) cryptorchid on day 3 with sham operation at three weeks and orchiopexy at two months (02M). All animals were sacrificed post-puberty at six months of age; the tests were fixed in situ by perfusion fixation, embedded in glycol methacrylate, and underwent morphometric analysis in a blinded fashion. The average seminiferous tubular diameter (STD) of the CON, SHAM, O3W, and O2M groups was 234, 160, 116, and 123 microns, respectively. The average testicular biopsy score count (TBSC) of the CON, SHAM, O3W and O2M groups was 9.0, 5.2, 3.5 and 3.5, respectively. There is no significant difference in STD or TBSC between the O3W and O2M cryptorchid groups, and values for both of these groups were significantly different from those of the SHAM group. In addition, a significant effect of sham operation was demonstrated. These results demonstrate no advantage of very early orchiopexy in this model, and are consistent with the clinical literature which, in general, shows reduced reproductive potential of a cryptorchid testis after orchiopexy.

Age Factors↗
PubMed1989

Effects of experimental varicocele require neither adrenal contribution nor venous reflux.

Experimental left varicocele (ELV) is known to induce bilateral changes in the rat testis that, where comparisons are possible, are similar to the changes induced by unilateral varicocele in the human. In the present study, we have determined whether or not left adrenal products are important to the changes induced by ELV and whether or not reflux of left renal vein content occurs in the ELV rat. In the first study, testicular blood flow and temperature were studied in control animals and those with ELV, left adrenalectomy (LAX), or ELV + LAX. Control left and right testicular blood flow (33.6 +/- 0.8 and 33.6 +/- 1.5 ml./min./100 gm. tissue respectively) was significantly elevated by ELV (to 39.9 +/- 0.9 and 41.2 +/- 2.7 ml./min./100 gm. tissue, respectively) and the difference between abdominal and testicular temperatures (delta T) was significantly reduced. Control delta T's for right and left testes were 3.2 +/- 0.2C and 3.2 +/- 0.2C, respectively, and right and left delta T's for ELV animals were 2.0 +/- 0.3 degrees C and 2.0 +/- 0.3C, respectively. These blood flow and temperature changes also occurred when ELV animals were subjected to simultaneous LAX. Additionally, when 85Sr-labelled microspheres were infused into the left renal vein, they did not appear in either left or right testes of ELV animals. We conclude that there is no evidence for reflux down the spermatic vein in ELV in rats and adrenal products do not reach the testis via this route after being secreted into the renal vein. We raise the suggestion that the same may be true in the human.

Adrenal Glands↗
PubMed1989

Sulfated oviductal glycoproteins in the rabbit: quantitation by competitive enzyme-linked immunosorbent assay.

The rabbit oviductal epithelium synthesizes and secretes a family of antigenically related, sulfated oviductal glycoproteins (SOG). Anti-SOG monoclonal antibodies (Mabs) were produced and two (Mab 1 and Mab 2) were selected for further characterization. Periodate oxidation of Western blots of oviductal fluid did not affect the binding of Mab 1 or Mab 2, thus suggesting that these antibodies recognized protein rather than carbohydrate epitopes on SOG. The specificity of Mab 1 was determined by Western blot analysis of tissues obtained from estrous rabbits and from the male rabbit reproductive tract. SOG was identified in tissue extracts of both the oviductal ampulla and isthmus. Cervix was the only non-oviductal tissue with which Mab 1 cross-reacted. Mab 1 was used to isolated SOG from whole oviductal fluid by immuno-affinity chromatography. Affinity-purified SOG and Mab 1 were used to develop a quantitative, SOG-specific, competitive enzyme-linked immunosorbent assay. This assay was used to quantify SOG in rabbit oviductal fluid collected during estrus and pseudopregnancy. SOG secretion during pseudopregnancy was resolved into two transient episodes of increased secretion. Maximum SOG secretion (X = 1039 +/- 199 micrograms/day) occurred within 48 h of the induction of pseudopregnancy. A second period of enhanced SOG secretion (X = 308 +/- 46 micrograms/day) occurred during the fifth and sixth days of pseudopregnancy. Baseline SOG secretion occurred during estrus at approximately 60% of maximum postovulatory secretion.

Animals↗
PubMed1989

Effect of steroid hormones on sulfated oviductal glycoprotein secretion by oviductal explants in vitro.

Explants of rabbit ampullary and isthmic tissue were cultured 4 days with and without exogenous steroids, and the sulfated oviductal glycoprotein (SOG) concentration in the explant culture supernatants was determined. Tissues cultured with progesterone plus estrogen secreted significantly more SOG than control tissues, whereas tissues cultured with estrogen alone did not. Ampullary tissues cultured with progesterone plus estrogen secreted significantly more SOG than control tissues on Days 2 and 3, whereas SOG secretion by isthmic tissues was significantly above control secretion on Day 4. Ampullary and isthmic tissues differed significantly in their secretory capacity. Maximum ampullary SOG secretion was approximately 650 ng SOG/mg tissue/day. Maximum isthmic SOG secretion was approximately 30 ng SOG/mg tissue/day. These findings suggest that the oviduct is composed of discrete functional regions that provide support to gametes and developing embryos through the unique secretory characteristics of each region.

Animals↗
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↗