Transient receptor potential channels TRPC1/TRPC6 regulate lamina cribrosa cell extracellular matrix gene transcription and proliferation.

The lamina cribrosa (LC) in glaucoma is with augmented production of extracellular matrix proteins (ECM) and connective tissue fibrosis. Fundamental pathological mechanisms for this fibrosis comprise fibrotic growth factors and oxidative stress. Transient receptor potential canonical channels (TRPC) channels play a key role in ECM fibrosis. Here, we study TRPC expression in glaucomatous LC cells, and investigate the role of TRPC in oxidative stress induced-profibrotic ECM gene transcription and cell proliferation in normal LC cells. Age-matched human LC cells (normal, n = 3 donors; glaucoma, n = 3 donors) were used. Hydrogen peroxide (H2O2, 100 µM), was used to induce oxidative stress in LC cells in the presence or absence of the pan TRPC inhibitor SKF96365 (10 µM) or knockdown of TRPC1/6 with siRNA. After treatments, ECM gene transcription, LC cell viability and proliferation and the phosphorylation of the transcription factor NFATc3, were measured using real time RT-PCR, colorimetric cell counting with the methyl-thiazolyl tetrazolium salt (MTS) assay, and Western immunoblotting, respectively. Results showed that TRPC1/C6 transcript and protein expression levels were significantly (p < 0.05) enhanced in glaucoma LC cells. Both SKF96365 and siRNA-TRPC1/C6 treatments significantly reduced the oxidative stress induced-ECM gene expression (transforming growth factor-ß1 (TGFß1), alpha smooth muscle actin (α-SMA), and collagen type 1A1 (Col1A1)), and cell proliferation in normal and glaucoma LC cells. Also, SKF96365 treatment inhibited the H2O2-induced NFATc3 protein dephosphorylation in LC cells. In conclusion, TRPC1/C6 expression is enhanced in glaucoma LC cells. These channels may contribute to oxidative stress-induced ECM gene transcription and cell proliferation in normal and glaucoma LC cells through Ca2+-NFATc3 signaling pathway mechanism. TRPC1 and TRPC6 channels could be important therapeutic targets to prevent ECM remodeling and fibrosis development in glaucoma optic neuropathy.

Assessing the effectiveness of a naturally occurring population-level physical activity intervention for children.

OBJECTIVES: The aim of the study was to assess the impact of a recreation access pass on grade 5 children's physical activity (PA) levels. STUDY DESIGN: This is a pre-post evaluation of a population-level community-based intervention. METHODS: All grade 5 students in (London, Ontario, Canada) were invited to participate in the [ACT-i-Pass] program (G5AP) in May 2014. A total of 643 children completed surveys, that included Physical Activity Questionnaire for Children (PAQ-C), at baseline (October 2014) and 6-month follow-up (April 2015). Difference in the means t-test compared PAQ-C scores between baseline and follow-up for the sample and subgroups. Multiple regression analysis tested associations between change in PAQ-C scores and intrapersonal-, interpersonal-, and physical environment-level variables. RESULTS: PA increased significantly from baseline to 6-month follow-up. Girls, visible minorities, immigrants, and children with low parental support experienced significant increases in PA. Regression found girls benefitted from the G5AP significantly more than boys, and lower parental support is related to increases in PA. CONCLUSION: The findings indicate that collaboratively developed, community-based interventions can significantly increase children's PA levels, particularly among subgroups with traditionally lower PA. The pre-post evaluation of this community-based intervention provides useful evidence for developing policies and programs aimed at making population-level improvements in children's PA levels.

Effect of ocular hypertension on the pattern of retinal ganglion cell subtype loss in a mouse model of early-onset glaucoma.

Glaucoma is a neurodegenerative disease with elevated intraocular pressure as one of the major risk factors. Glaucoma leads to irreversible loss of vision and its progression involves optic nerve head cupping, axonal degeneration, retinal ganglion cell (RGC) loss, and visual field defects. Despite its high global prevalence, glaucoma still remains a major neurodegenerative disease. Introduction of mouse models of experimental glaucoma has become integral to glaucoma research due to well-studied genetics as well as ease of manipulations. Many established inherent and inducible mouse models of glaucoma are used to study the molecular and physiological progression of the disease. One such model of spontaneous mutation is the nee model, which is caused by mutation of the Sh3pxd2b gene. In both humans and mice, mutations disrupting function of the SH3PXD2B adaptor protein cause a developmental syndrome including secondary congenital glaucoma. The purpose of this study was to characterize the early onset nee glaucoma phenotype on the C57BL/6J background and to evaluate the pattern of RGC loss and axonal degeneration in specific RGC subtypes. We found that the B6.Sh3pxd2bnee mutant animals exhibit glaucoma phenotypes of elevated intraocular pressure, RGC loss and axonal degeneration. Moreover, the non-image forming RGCs survived longer than the On-Off direction selective RGCs (DSGC), and the axonal death in these RGCs was independent of their respective RGC subtype. In conclusion, through this study we characterized an experimental model of early onset glaucoma on a C57BL/6J background exhibiting key glaucoma phenotypes. In addition, we describe that RGC death has subtype-specific sensitivities and follows a specific pattern of cell death under glaucomatous conditions.

Oxidative stress, mitochondrial dysfunction and calcium overload in human lamina cribrosa cells from glaucoma donors.

PURPOSE: Oxidative stress is implicit in the pathological changes associated with glaucoma. The purpose of this study was to compare levels of oxidative stress in glial fibrillary acid-negative protein (GFAP) lamina cribrosa (LC) cells obtained from the optic nerve head (ONH) region of 5 normal (NLC) and 4 glaucomatous (GLC) human donor eyes and to also examine mitochondrial function and calcium homeostasis in this region of the ONH. METHODS: Intracellular reactive oxygen species (ROS) production was examined by a thiobarbituric acid reactive substances (TBARS) assay which measures malondialdehyde (MDA), a naturally occurring product of lipid peroxidation and is used as an indicator of oxidative stress. Mitochondrial membrane potential (MMP) and intracellular calcium ([Ca(2+)](i)) levels were evaluated by flow cytometry using the JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetrabenzimidazolecarbocyanine iodide) and fluo-4/AM probes respectively. Anti-oxidant and Ca(2+) transport system gene and protein expression were determined by real time polymerase chain reaction (RT-PCR) using gene-specific primer/probe sets and western immunoblotting, respectively. RESULTS: Intracellular ROS production was increased in GLC compared to NLC (27.19 ± 7.05 µM MDA versus 14.59 ± 0.82 µM MDA, p < 0.05). Expression of the anti-oxidants Aldo-keto reductase family 1 member C1 (AKR1C1) and Glutamate cysteine ligase catalytic subunit (GCLC) were significantly lower in GLC (p = 0.02) compared to NLC control. MMP was lower in GLC (57.5 ± 6.8%) compared to NLC (41.8 ± 5.3%). [Ca(2+)](i) levels were found to be higher (p < 0.001) in GLC cells compared to NLC. Expression of the plasma membrane Ca(2+)/ATPase (PMCA) and the sodium-calcium (NCX) exchangers were lower, while intracellular sarco-endoplasmic reticulum Ca(2+)/ATPase 3 (SERCA) expression was significantly higher in GLC compared to NLC. Subjection of NLC cells to oxidative stress (200 µM H(2)0(2)) reduced expression of Na(+)/Ca2(+) exchanger 1 (NCX 1), plasma membrane Ca2+ ATPase 1 (PMCA 1), and PMCA 4 as determined by RT-PCR. CONCLUSIONS: Our data finds evidence of oxidative stress, mitochondrial dysfunction and impaired calcium extrusion in GLC cells compared to NLC cells and suggests their importance in the pathological changes occurring at the ONH in glaucoma. Future therapies may target reducing oxidative stress and / or [Ca(2+)](i).

Ubiquitous nonimmunoglobulin p-azobenzenearsonate-binding molecules from lymphoid cells.

A ubiquitous nonimmunoglobulin molecule that binds p-azobenzenearsonate (ABA) has been detected in the cytoplasm of several murine cell lines, including T cell hybridomas as well as in normal liver and spleen. Similar to many recently described antigen-specific T cell factors, this ABA-binding protein has a 62,000 mol wt, and, when analyzed by direct binding, the molecule reacts with several different rabbit anti-idiotypic antisera specific to the ABA system. The presence of this antigen-specific, "idiotype positive" molecule in many different cells indicates that it is not an important immunoregulatory molecule.

Cross-linked actin networks (CLANs) in bovine trabecular meshwork cells.

A cytoskeletal feature of human trabecular meshwork (HTM) cells in vitro and ex vivo is the presence of cross-linked actin networks (CLANs) that are abundant in a proportion of TM cells exposed to dexamethasone (DEX) and also in cells from glaucoma patients. We wished to determine whether CLANs were present in the bovine trabecular meshwork (BTM), whether they were similarly induced by dexamethasone and whether the structures were comparable to CLANs in HTM cells. Cultures of HTM and BTM cells and ex vivo dissections of BTM tissue were stained with phalloidin (F-actin) and propidium iodide (nuclei) and imaged by confocal microscopy, thereafter being subjected to image analysis. Some CLAN-like structures were identified in ex vivo BTM tissue cultured with and without DEX. However we found that BTM cells in culture produced abundant CLANs when exposed to DEX; comparable to the best response from HTM cells. The CLANs were of similar dimensions and morphology to those found in human cells and they had a similar half life of 2 or 3 days following the removal of DEX. This work demonstrates that BTM cells provide a suitable model for future investigations of CLAN formation and function. BTM cultures are sufficiently hardy to thrive in low serum and serum-free conditions so we were able to show that aqueous humor stimulates CLAN formation in the target cells. Future research is directed at identifying the aqueous component(s) responsible for CLAN production.

Absence of pyruvate decarboxylase activity in man: a cause of congenital lactic acidosis.

A complete deficiency in the pyruvate dehydrogenase system activity contributed to the death of a 6-month-old infant with congenital lactic acidosis. The enzymatic block could be isolated to the first component, pyruvate decarboxylase (E1) of the pyruvate dehydrogenase complex. This enzymatic deficiency allowed a demonstration of an "intercomplex" exchange of the components of the mammalian pyruvate dehydrogenase system and indicated that the first component is normally present in an apparent excess.

Identification of a gene that causes primary open angle glaucoma.

Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.

Subtype-specific response of retinal ganglion cells to optic nerve crush.

Glaucoma is a neurodegenerative disease with retinal ganglion cell (RGC) loss, optic nerve degeneration and subsequent vision loss. There are about 30 different subtypes of RGCs whose response to glaucomatous injury is not well characterized. The purpose of this study was to evaluate the response of 4 RGC subtypes in a mouse model of optic nerve crush (ONC). In this study, we also evaluated the pattern of axonal degeneration in RGC subtypes after nerve injury. We found that out of the 4 subtypes, transient-Off α RGCs are the most susceptible to injury followed by On-Off direction selective RGCs (DSGC). Non-image forming RGCs are more resilient with ipRGCs exhibiting the most resistance of them all. In contrast, axons degenerate irrespective of their retinal soma after ONC injury. In conclusion, we show that RGCs have subtype specific cell death response to ONC injury and that RGC axons disintegrate in an autonomous fashion undergoing Wallerian degeneration. These discoveries can further direct us towards effective diagnostic and therapeutic approaches to treat optic neuropathies, such as glaucoma.

Effects of aminoglutethimide on delta 5-androstenediol metabolism in postmenopausal women with breast cancer.

delta-5-Androstene-3 beta, 17 beta-diol has potential estrogenic activity because it is known to bind to receptors and translocate to the nucleus of certain estrogen target tissues. Its role in the biology of breast cancer is unclear. Aminoglutethimide plus hydrocortisone ("medical adrenalectomy") has been used to treat postmenopausal women with metastatic breast cancer. We studied delta 5-androstene-3 beta, 17 beta-diol metabolism in postmenopausal women with breast cancer before and during aminoglutethimide-plus-hydrocortisone therapy, utilizing the constant infusion technique. The metabolic clearance rate for five subjects was 799 +/- 89 liters/24 hr (470 +/- 47 liters/24 hr/sq m) before and 751 +/- 93 liters/24 hr (444 +/- 57 liters/24 hr/sq m) during therapy. Plasma delta 5-androstene-3 beta, 17 beta-diol and delta 5-androstene-3 beta, 17 beta-diol free index decreased despite absence of change in the metabolic clearance rate. Increased dehydroepiandrosterone/delta 5-androstene-3 beta, 17 beta-diol conversion ratios in individual patients suggested an increase in 17 beta-hydroxysteroid dehydrogenase activity during therapy. There were no alterations in the formation of the estrogen precursors testosterone and delta 4-androstene-3,17-dione.

The insect brain (Na+ + K+)-ATPase. Binding of ouabain in the hawk moth, Manduca sexta.

(1) A quantitative study has been made of the binding of ouabain to the (Na+ + K+)-ATPase in homogenates prepared from brain tissue of the hawk moth, Manduca sexta. The results have been compared to those obtained in bovine brain microsomes. (2) The insect brain (Na+ + K+)-ATPase will bind ouabain either in the presence of Mg2+ and Pi, ('Mg2+, Pi' conditions) or in the presence of Na+, Mg2+, and an adenine nucleotide ('nucleotide' conditions) as is the case for the bovine brain (Na+ + K+)-ATPase. The binding conditions did not alter the total number of receptor sites measured at high ouabain concentrations in either tissue. (3) Potassium ion decreases the affinity (increases the KD) of ouabain to the M. sexta brain (Na+ + K+)-ATPase under both binding conditions. However, ouabain binding is more sensitive to K+ inhibition under the nucleotide conditions. In bovine brain ouabain binding is equally sensitive to K+ inhibition under both conditions. (4) The enzyme-ouabain complex has a rate of dissociation that is 10-fold faster in the M. sexta preparation than in the bovine brain preparation. Because of this, the M. sexta (Na+ + K+)-ATPase has a higher KD for ouabain binding and is less sensitive to inhibition by ouabain than the bovine brain enzyme. (5) This data supports the hypothesis that two different conformational states of the M. sexta (Na+ + K+)-ATPase can bind ouabain.

Effects of glucocorticoids on the trabecular meshwork: towards a better understanding of glaucoma.

Glucocorticoid effects on the human trabecular meshwork can be used as a model system in which to study glaucomatous damage to the trabecular meshwork. One of the most important risk factors for glaucoma is an elevated intraocular pressure. The administration of glucocorticoids also can cause elevated intraocular pressure in some individuals. In addition, there is suggestive evidence linking glucocorticoids with the development of glaucoma. Glucocorticoids cause multiple effects on the human trabecular meshwork including changes in extracellular matrix metabolism, organisation of the cytoskeleton, and changes in gene expression and cell function. New discoveries on the molecular mechanisms of glucocorticoid receptor action provide new opportunities to study the possible role of this receptor in the development of glaucoma. For example, alternate spliced forms of the glucocorticoid receptor, glucocorticoid receptor response element half-sites, numerous modulatory factors, and direct effects of nuclear transcription factors have been recently described. Other recent information has shown that the new glaucoma gene (GLC1A/myocilin) is induced in the human trabecular meshwork by glucocorticoids. Although the exact function of myocilin is currently unknown, it offers the opportunity to dissect the molecular pathways regulating aqueous humor outflow. Future challenges include determining (1) which glucocorticoid effects in the human trabecular meshwork are responsible for elevated intraocular pressure; and (2) the significance of these findings to the development of glaucoma.

Neuritin 1 promotes retinal ganglion cell survival and axonal regeneration following optic nerve crush.

Neuritin 1 (Nrn1) is an extracellular glycophosphatidylinositol-linked protein that stimulates axonal plasticity, dendritic arborization and synapse maturation in the central nervous system (CNS). The purpose of this study was to evaluate the neuroprotective and axogenic properties of Nrn1 on axotomized retinal ganglion cells (RGCs) in vitro and on the in vivo optic nerve crush (ONC) mouse model. Axotomized cultured RGCs treated with recombinant hNRN1 significantly increased survival of RGCs by 21% (n=6-7, P<0.01) and neurite outgrowth in RGCs by 141% compared to controls (n=15, P<0.05). RGC transduction with AAV2-CAG-hNRN1 prior to ONC promoted RGC survival (450%, n=3-7, P<0.05) and significantly preserved RGC function by 70% until 28 days post crush (dpc) (n=6, P<0.05) compared with the control AAV2-CAG-green fluorescent protein transduction group. Significantly elevated levels of RGC marker, RNA binding protein with multiple splicing (Rbpms; 73%, n=5-8, P<0.001) and growth cone marker, growth-associated protein 43 (Gap43; 36%, n=3, P<0.01) were observed 28 dpc in the retinas of the treatment group compared with the control group. Significant increase in Gap43 (100%, n=5-6, P<0.05) expression was observed within the optic nerves of the AAV2-hNRN1 group compared to controls. In conclusion, Nrn1 exhibited neuroprotective, regenerative effects and preserved RGC function on axotomized RGCs in vitro and after axonal injury in vivo. Nrn1 is a potential therapeutic target for CNS neurodegenerative diseases.

Calcium channel blockade reduces mechanical strain-induced extracellular matrix gene response in lamina cribrosa cells.

PURPOSE: This study examines the effect of the L-type calcium channel blocker verapamil on mechanical strain-induced extracellular matrix genes in optic nerve head lamina cribrosa (LC) cells. METHODS: Changes in LC cell intracellular calcium [Ca(2+)]i following hypotonic cell membrane stretch were measured with the fluorescent probe fura-2/AM. Fluorescence intensity was measured, after labelling, by calcium (Ca2+) imaging confocal microscopy. Confluent human LC cell cultures were serum starved for 24 h prior to exposure to cyclical mechanical strain (1 Hz, 15%) for 24 h in the presence or absence of verapamil (10 mm). Transforming growth factor-ß 1 (TGF-ß1), collagen 6A3 (COL6A3) and chondroitin sulfate proteoglycan 2 (CSPG2) mRNA expression levels were assessed by quantitative RT-PCR. RESULTS: Hypotonic cell membrane stretch of LC cells from normal donors significantly increased [Ca2+]i (p<0.05). Exposure to cyclical mechanical strain (15% strain) produced a statistically significant increase in the three matrix genes that were examined (TGF-ß1, COL6A3 and CSPG2). This response in both cyclical and mechanical stretch was significantly reduced by pretreating LC cells with the L-type calcium channel blocker verapamil (p<0.05). CONCLUSIONS: This study provides evidence of a novel mechanotransduction pathway linking mechanical strain, cation channel function and the induction of LC cell matrix gene transcription. This highlights the potential involvement of calcium influx in the activation of matrix remodelling responses in the optic nerve head and supports the rationale that calcium channel blockers may attenuate disease progression in glaucoma.

Epithelial-stromal interactions in the regulation of rat ventral prostate function: identification and characterization of pathways for androgen metabolism in isolated cell types.

Androgen metabolism plays a significant role in the androgen regulation of prostate cell function. In this report the various pathways for androgen metabolism in primary cultures of rat ventral prostate epithelial and stromal cells were identified and characterized by in vitro whole cell assays, using HPLC. Confluent cultures of both cell types were incubated with supraphysiological concentrations (50 nM) of tritiated androgens (testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha(and 3 beta), 17 beta-diols, and delta 4-androstene-3,17-dione), and the metabolites were analyzed at several time points over a 24-h period. The metabolism studies indicated that 5 alpha-reductase activity, the oxidative reactions of 3 alpha-, 3 beta-, and 17 beta-hydroxysteroid oxidoreductases, and the reductive reaction of 3 beta-hydroxysteroid oxidoreductase were expressed at significantly higher levels in epithelial cells compared to stromal cells. The reductive reactions of 3 alpha- and 17 beta-hydroxysteroid oxidoreductases were similar in both cell types. In contrast, stromal cells exhibited substantially higher levels of 6 alpha/7 alpha-hydroxylase activity. In addition, stromal cells were capable of metabolizing 5 alpha-dihydrotestosterone directly to a new unidentified polar androgen metabolite (HO5 alpha-DHT). Overall, epithelial cells were approximately 29 times more capable than stromal cells of forming the biologically active androgen 5 alpha-dihydrotestosterone. Conversely, stromal cells were more capable of forming biologically inactive polar androgen metabolites.

Differential androgen modulation of acid phosphatase isozymes in primary cultures of rat ventral prostate epithelial and stromal cells.

The influence of androgen on prostate differentiated cell function was investigated using primary cultures of rat ventral prostate epithelial and stromal cells developed from sexually immature animals (21 days of age). As a biochemical marker of androgen action, total acid phosphatase activity, which comprises both the secretory and lysosomal isoforms, was measured. Testosterone increased total acid phosphatase activity approximately 2-fold in epithelial cell cultures. This increase occurred only after the cessation of cell proliferation (i.e. upon reaching a confluent monolayer). In contrast, stromal cells showed no significant change in total acid phosphatase activity in response to androgen. Polyacrylamide gel isoelectric focusing of total acid phosphatase activity from epithelial and stromal cell extracts revealed that secretory acid phosphatase activity was localized exclusively in the epithelial cells while lysosomal acid phosphatase activity was present in both cell types. Furthermore, the androgen-induced increases in epithelial total acid phosphatase activity were found to result from increases in the secretory isoform.

Dehydroepiandrosterone: kinetics of metabolism in normal men and women.

The single injection and constant infusion techniques were utilized to study the kinetics of dehydroepiandrosterone (DHEA) metabolism and its peripheral conversion to several other C19-steroids including C19-steroid sulfates. The MCRs (mean +/- SEM) for normal men and normal women were 1866 +/- 144 and 1901 +/- 87 liters/24 h, respectively. The single injection technique yielded values for rate constants (units) and volumes of distribution (1) as follows: K1, 42.6 +/- 7.7 for men and 37.1 +/- 5.0 for women; K2, 64.3 +/- 11.2 for men and 55.5 +/- 5.0 for women; K2, 64.3 +/- 11.2 for men and 55.5 +/- 5.0 for women; V1, 38.5 +/- 6.0 for men and 33.7 +/- 2.5 for women; V2, 30.4 +/- 7.3 for men and 27.5 +/- 9.9 for women. The constant infusion technique yielded values for the conversion ratios for the transformation of DHEA to several products: delta 5-androstene-3 beta, 17 beta-diol to DHEA of 0.10 +/- 0.01 for men and 0.16 +/- 0.03 for women, delta 4-androstenedione to DHEA of 0.04 +/- 0.01 for men and 0.07 +/- 0.02 for women, DHEA sulfate (DHEAS) to DHEA of 6.36 +/- 0.81 for men and 10.09 +/- 0.87 for women, delta 5-androstene-3 beta, 17 beta-diol sulfate to DHEA of 0.42 +/- 0.06 for men and 0.50 +/- 0.04 for women, and androsterone sulfate to DHEA of 1.11 +/- 0.13 for men and 2.06 +/- 0.18 for women. The ratios for the conversion to DHEA sulfate and androsterone sulfate were significantly higher for women than men. The plasma concentrations of DHEA were 8.50 +/- 0.95 and 8.75 +/- 1.01 ng/ml for men and women, respectively. The calculated production rates for DHEA were 16.34 +/- 2.66 and 16.19 +/- 1.78 mg/24 h for men and women, respectively. There was no sex difference in the binding of DHEA to plasma proteins and this is reflected in the lack of sex difference in the MCRs. Calculations indicate that DHEA is a major precursor of circulating delta 5-diol.

Delta5-androstenediol: kinetics of metabolism and binding to plasma proteins in normal men and women.

Using the constant fusion and single injection technique the metabolic clearance rates (mean +/- SEM) for delta5-androstene-3beta, 17beta-diol (delta5-idol) were measured for 19 normal men (1311 +/- 67 1/24 h) and 10 normal women (858 +/- 63 1/24 h). The constant infusion technique yielded values for the conversation ratios for the transformation of delta5-diol to several products: dehydroepiandrosterone (DHEA)/delta5-diol of 0.06+/-0.01 for men and 0.05 +/- 0.01 for women, of delta5-diol sulfate/delta5-diol of 0.45 +/- 0.04 for men and 0.52 +/- 0.03 for women and of DHEA sulfate/delta5-diol of 5.53 +/- 0.26 for men and 5.02 +/- 0.42 for women. The single injection technique yielded rate constants (units) and volumes of distribution (liters) for delta5-diol; Ki = 34.3 +/- 4.3 for men and 35.0 +/- 3.9 for women, K2 = 63.7 +/- 4.1 for men and 75.1 +/- 4.2 for women, V1 = 23.1 +/- 3.2 for men and 11.9 +/- 2.3 for women, V2 = 14.8 +/- 3.7 for men and 9.2 +/- 3.2 for women. The mean delta5-diol plasma concentration was 1.08 +/- 0.10 ng/ml for 12 men and 1.17 +/- 0.16 ng/ml for 9 women. (he calculated blood production rates for delta5-diol were 1357 +/- 117 mug/24 h for 12 men and 969 +/- 131 mug/24 h for 9 women. The per cent binding (equilibrium dialysis) was higher for women (94.9 +/- 0.3) than for men (93.0 +/- 0.2). Paper electrophoresis showed that significant fractions of 3H-delta5-diol migrated with both the beta-globulin and albumin fractions. Estrogen administration to two normal men increased the per cent binding of delta5-diol to plasma proteins and decreased the metabolic clearance rate towards the values found for normal women.

PIP: Studies on the kinetics of delta 5-androstene-3beta,17beta-diol (delta 5-diol) metabolism and on the binding of delta 5-diol to plasma proteins in normal men and women are reported. Using the constant infusion and single injection technique the mean metabolic clearance rate for delta 5-diol was found to be 1311 1/24 hours in 19 normal men and 858 1/24 hours in 10 normal women (p less than .01). The constant infusion technique yielded values for the conversion ratios for the transformation of delta 5-diol to dehydroepiandrosteroe (DHEA)/delta 5-diol of .06 for men and .05 for women, of delta 5-diol sulfate/delta 5-diol .45 for men and .52 for women. The single injection technique yeilded rate constants (units=K) and volumes of distribution (liters) for delta 5-diol as K1=34.3 for men and 35 for women, K2-63.7 for men and 75.1 for women, V1=23.2 for men and 11.9 for women, V2-14.8 for men and 9.2 for women. mean delta 5-diol concentration was 1.08 and 1.17 ng/ml for 12 men and 9 women, respectively, while blood production rates were 1357 and 969 mcg/24 hours, respectively. Using equilibrium dialysis, the binding was 93 for men and 94.9 for women (p less than .01). Paper electrophoresis revealed significantly (p less than .01) more tritiated delta 5-diol associated with the beta-globulin area for women than for men. Estrogen administration to 2 normal men increased the percent binding of delta 5-diol to plasma proteins and decreased the metabolic clearance rate.

Targeted inactivation of the Ren-2 gene in mice.

Several recent studies have demonstrated that ablation of genes of the renin-angiotensin system can have wide-ranging and sometimes unexpected effects. Renin is directly involved in blood pressure regulation and is encoded by a single gene in most mammals. Wild mouse strains and some inbred laboratory strains have a duplicated renin gene (Ren-2), the physiological significance of which is unclear. Significant differences exist in the structure and expression of these renin genes, but as yet, no distinct biological function that distinguishes these genes has been defined. We have used gene targeting to discover the effects of inactivating the duplicated (Ren-2) gene in strain 129 mice, and we show that mice lacking the Ren-2 gene are viable and healthy. There appear to be no histopathological differences in renin-expressing tissues between Ren-2-null mice and their controls. Studies of our Ren-2-null mice allow, for the first time, a direct evaluation of the ability of the Ren-1d gene to regulate blood pressure in the absence of expression of the Ren-2 enzyme. We observed no alteration to blood pressure in adult mice homozygous for the mutated Ren-2 gene, even though the concentration of active renin is increased and of prorenin is decreased in plasma of these mice. Ren-1d is therefore capable of regulating normal blood pressure and despite a different tissue expression profile, is functionally equivalent to Ren-1c.

Multiple molecular forms of arylsulfatase A in different forms of metachromatic leukodystrophy (MLD).

Arylsulfatase A (ARA) can be separated into six to eight individual enzymatic bands of activity by isoelectric focusing on cellulose acetate membranes. The residual ARA activity in juvenile metachromatic leukodystrophy (MLD) has a single band of activity with apI of 5.5, whereas the residual ARA in the late infantile form of MLD has three bands of activity with pI range of from 5.4 to 5.8. The technique of isoelectric focusing on cellulose acetate membranes demonstrates enzymatic differences which can be correlated with the clinical form of the disease.