Affinity imaging mass spectrometry (AIMS): high-throughput screening for specific small molecule interactions with frozen tissue sections.

A novel screening system, using affinity imaging mass spectrometry (AIMS), has been developed to identify protein aggregates or organ structures in unfixed human tissue. Frozen tissue sections are positioned on small (millimetre-scale) stainless steel chips and incubated with an extensive library of small molecules. Candidate molecules showing specific affinity for the tissue section are identified by imaging mass spectrometry (IMS). As an example application, we screened over a thousand compounds against Alzheimer's disease (AD) brain tissue and identified several compounds with high affinity for AD brain sections containing tau deposits compared to age-matched controls. It should also be possible to use AIMS to isolate chemical compounds with affinity for tissue structures or components that have been extensively modified by events such as oxidation, phosphorylation, acetylation, aggregation, racemization or truncation, for example, due to aging. It may also be applicable to biomarker screening programs.

Increased insulin sensitivity and hypoglycaemia in mice lacking the p85 alpha subunit of phosphoinositide 3-kinase.

The hallmark of type 2 diabetes, the most common metabolic disorder, is a defect in insulin-stimulated glucose transport in peripheral tissues. Although a role for phosphoinositide-3-kinase (PI3K) activity in insulin-stimulated glucose transport and glucose transporter isoform 4 (Glut4) translocation has been suggested in vitro, its role in vivo and the molecular link between activation of PI3K and translocation has not yet been elucidated. To determine the role of PI3K in glucose homeostasis, we generated mice with a targeted disruption of the gene encoding the p85alpha regulatory subunit of PI3K (Pik3r1; refs 3-5). Pik3r1-/- mice showed increased insulin sensitivity and hypoglycaemia due to increased glucose transport in skeletal muscle and adipocytes. Insulin-stimulated PI3K activity associated with insulin receptor substrates (IRSs) was mediated via full-length p85 alpha in wild-type mice, but via the p50 alpha alternative splicing isoform of the same gene in Pik3r1-/- mice. This isoform switch was associated with an increase in insulin-induced generation of phosphatidylinositol(3,4,5)triphosphate (PtdIns(3,4,5)P3) in Pik3r1-/- adipocytes and facilitation of Glut4 translocation from the low-density microsome (LDM) fraction to the plasma membrane (PM). This mechanism seems to be responsible for the phenotype of Pik3r1-/- mice, namely increased glucose transport and hypoglycaemia. Our work provides the first direct evidence that PI3K and its regulatory subunit have a role in glucose homeostasis in vivo.

Prevalence of the metabolic syndrome in kidney transplantation.

OBJECTIVES: We investigated the prevalence of the metabolic syndrome (MS) in kidney transplantation patients and assessed its development based on plasma adiponectin levels and the results of an oral glucose tolerance test (OGTT). METHODS: We performed a cross-sectional study of 94 recipients with stable graft function who underwent kidney transplantation between January 1999 and October 2008. The presence of MS was determined using National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria with body mass index (BMI) used in place of waist circumference. In addition, we measured plasma adiponectin level and performed a 75-g oral GTT. RESULTS: Fourteen (14.9 %) recipients suffered from MS for a mean period of 46.7 months (range, 1-106) after transplantation. BMI at the time of transplantation was significantly greater in the MS group (23.4 +/- 3.24 vs 20.1 +/- 2.50; P < .0001), whereas plasma adiponectin level was significantly lower (11.95 +/- 5.13 vs 17.71 +/- 8.47; P = .0158). The insulinogenic index values were similar, whereas the homeostatic model assessment of insulin resistance was greater in the MS group (2.598 +/- 1.918 vs 1.340 +/- 0.934; P = .0002). CONCLUSION: The level of adiponectin, which was lower in kidney transplant recipients who developed MS, was negatively correlated with insulin sensitivity. We concluded that a low adiponectin level may correlate with the prevalence of MS in kidney transplantation in association with impaired insulin sensitivity.

Troglitazone increases the number of small adipocytes without the change of white adipose tissue mass in obese Zucker rats.

Troglitazone (CS-045) is one of the thiazolidinediones that activate the peroxisome proliferator-activated receptor gamma (PPARgamma), which is expressed primarily in adipose tissues. To elucidate the mechanism by which troglitazone relieves insulin resistance in vivo, we studied its effects on the white adipose tissues of an obese animal model (obese Zucker rat). Administration of troglitazone for 15 d normalized mild hyperglycemia and marked hyperinsulinemia in these rats. Plasma triglyceride level was decreased by troglitazone in both obese and lean rats. Troglitazone did not change the total weight of white adipose tissues but increased the number of small adipocytes (< 2,500 micron2) approximately fourfold in both retroperitoneal and subcutaneous adipose tissues of obese rats. It also decreased the number of large adipocytes (> 5,000 micron2) by approximately 50%. In fact, the percentage of apoptotic nuclei was approximately 2.5-fold higher in the troglitazone-treated retroperitoneal white adipose tissue than control. Concomitantly, troglitazone normalized the expression levels of TNF-alpha which were elevated by 2- and 1.4-fold in the retroperitoneal and mesenteric white adipose tissues of the obese rats, respectively. Troglitazone also caused a dramatic decrease in the expression levels of leptin, which were increased by 4-10-fold in the white adipose tissues of obese rats. These results suggest that the primary action of troglitazone may be to increase the number of small adipocytes in white adipose tissues, presumably via PPARgamma. The increased number of small adipocytes and the decreased number of large adipocytes in white adipose tissues of troglitazone-treated obese rats appear to be an important mechanism by which increased expression levels of TNF-alpha and higher levels of plasma lipids are normalized, leading to alleviation of insulin resistance.

Kidney transplantation in patients receiving dialysis treatment for more than 10 years.

In the present single center study, we analyzed 277 kidney transplant patients (procedures performed between February 1984 and February 2006) to determine the impact of long-term dialysis on kidney transplant outcomes. Forty-four had been treated prior to renal transplantation with dialysis for more than 10 years (range, 10.0-32.5 years, average, 16.6 years; Group I), while the remaining 233 recipients showed an average end-stage renal disease period of 2.8 years (range, 0-9.8 years; Group II). There were no significant differences in patient survivals between the 2 groups: 97.3% vs 97.4% at 1 year; 85.7% vs 92.4% at 5 years; 85.7% vs 90.7% at 10 years (P = .2347). Five Group I patients died: 2 from infections, 2 from liver dysfunction, and 1 from cerebral bleeding. These causes of death were similar to those among Group II patients. Graft survival was not significantly different between the 2 groups: 95% vs 88.8% at 1 year; 75.5% vs 76.5% at 5 years; 75.5% vs 65.5% at 10 years (P = .6264). Our results suggested that dialysis treatment for more than 10 years did not have negative effects on posttransplantation patient and graft survival.

Acute hyperglycemia provides an insulin-independent inducer for GLUT4 translocation in C2C12 myotubes and rat skeletal muscle.

GLUT4 translocation and activation of glucose uptake in skeletal muscle can be induced by both physiological (i.e., insulin, nerve stimulation, or exercise) and pharmacological (i.e., phorbol ester) means. Recently, we demonstrated that high glucose levels may mimic the effects of phorbol esters on protein kinase C (PKC) and insulin receptor function (J Biol Chem 269:3381-3386, 1994). In this study, we tested whether the previously described effects of phorbol esters on translocation of GLUT4 in myotubes in culture and also in rat skeletal muscle might be mimicked by glucose. We found that stimulation of C2C12 myotubes with both insulin (10(-7) mol/l, 5 min) and glucose (25 mmol/l, 10 min) induces a comparable increase of the GLUT4 content in the plasma membrane. To test whether this effect occurs in intact rat skeletal muscle as well, two different model systems were used. As an in vitro model, isolated rat hindlimbs were perfused for 80 min with medium containing 6 mmol/l glucose +/- insulin (1.6 x 10(-9) mmol/l, 40 min) or 25 mmol/l glucose. As an in vivo model, acute hyperglycemia (> 11 mmol/l glucose, 20 min) was induced in Wistar rats by intraperitoneal injection of glucose under simultaneous suppression of the endogenous insulin release by injection of somatostatin. In both models, subcellular fractions were prepared from hindlimb skeletal muscle, and plasma membranes were characterized by the enrichment of the marker enzyme alpha 1 Na(+)-K(+)-ATPase.(ABSTRACT TRUNCATED AT 250 WORDS)

Descriptive epidemiology of IDDM in Hokkaido, Japan: the Childhood IDDM Hokkaido Registry.

OBJECTIVE: To identify the incidence of IDDM with regard to sex, age, family history of diabetes, season, and 5-year period of childhood IDDM among children ages 0-14 years from a population-based epidemiological study in Hokkaido, Japan, from 1973 to 1992. RESEARCH DESIGN AND METHODS: Registration of all new IDDM cases in Hokkaido was conducted by the Childhood IDDM Hokkaido Registry Study Group from 1973 to 1992. The cases were selected from among 1) patients who were admitted to the member hospitals of the study group, 2) patients who answered a questionnaire distributed to hospitals and diabetic clinics throughout Hokkaido, and 3) patients whose cases were recorded in free-treatment medical records of urban and rural districts. The case ascertainment rate was estimated to be 100%. Differences in incidence with regard to sex, age, family history of diabetes, season, and year period were analyzed by the Poisson regression analysis by GENMOD. RESULTS: During the 20-year period studied, 396 cases (181 boys, 215 girls) of abrupt-onset IDDM were registered. Statistically significant differences in annual incidence were found according to sex (female), age (8-14 years), history (having no diabetes in family), season (spring), and 5-year period. CONCLUSIONS: This is the first population-based, long-term epidemiological study of childhood IDDM from Japan. We observed a significantly higher annual incidence (per 100,000/year) of IDDM in female subjects (1.81), older age-groups (2.25 for 8-14 years), subjects with no family history of diabetes (1.26), diabetes onset in the spring (2.20), and an increased trend over the 20 years. In addition, the heterogeneity of IDDM among Japanese children needs to be elucidated.

A new constitutively activating point mutation in the luteinizing hormone/choriogonadotropin receptor gene in cases of male-limited precocious puberty.

A single point mutation that encodes an aspartic acid (Asp578) to glycine substitution in the LH/CG receptor (LH/CGR) gene, D578G, was recently found in American patients with familial male-limited precocious puberty and in a Japanese patient with a sporadic form of the disorder. Transfection of the mutant, compared to the wild-type, LH/CGR complementary DNA into COS-7 cells results in higher basal cAMP production, but a normal agonist-induced response; the mutation is, therefore, proposed to constitutively activate Leydig cells and elevate serum testosterone, despite low levels of gonadotropin. In the current study we examined two additional Japanese patients with male-limited precocious puberty without a family history of the disease. We describe a heterozygous cytosine (C) to thymine (T) transition at nucleotide 1715 in both; the mutation encodes an alanine to valine substitution in codon 572 of transmembrane helix 6, A572V. Transfected into COS-7 cells, the A572V mutant exhibited the same constitutively high basal cAMP levels and normal agonist-induced cAMP response as the D578G mutant. We conclude that the constitutively higher cAMP levels caused by the A572V mutation led to Leydig cell activation and male-limited precocious puberty, as in the previously described D578G mutation. As the mother of one of the two patients had the same heterozygous mutation, this patient represents the first recognized case of inherited male-limited precocious puberty in the Japanese population. The previously described D578G mutant did not increase basal or agonist-induced inositol phosphate production in transfected COS-7 cells, or the number of LH/CGRs or their affinity for LH/CG. In contrast, transfection of the A572V mutation in COS-7 cells exhibited significantly higher inositol phosphate levels basally and at 10(-11) mol/L hCG, but significantly lower inositol phosphate levels at 10(-7) mol/L hCG. These data suggest that the A572V mutation of the LH/CGR may have effects on the guanine nucleotide binding protein which activates phospholipase C (Gq) coupling and phospholipase-C activation in addition to its effects on Gs coupling and activation of adenylyl cyclase. A572V-transfected cells also exhibited a higher affinity, despite an apparent decrease in the number of binding sites, for [125I]hCG, compared to transfectants with the wild-type LH/CGR. We hypothesize that these differences between the A572V and D578G mutations reflect a greater impact of the A572V mutation on receptor conformation.

Phe576 plays an important role in the secondary structure and intracellular signaling of the human luteinizing hormone/chorionic gonadotropin receptor.

Recent studies have identified multiple activating mutations in the sixth transmembrane domain of LH/chorionic gonadotropin receptor (LH/CGR) in patients with male-limited precocious puberty. Computer analysis suggested that these mutations had an effect on the secondary structure of the third cytoplasmic loop and sixth transmembrane domain, and that Phe576 was a critical conformational bridging residue between these regions that might be important for receptor activity. We made four amino acid substitutions of the Phe576 (F576I, F576G, F576Y, F576E) in the LH/CG receptor to analyze its functional role. Computer analysis of secondary structure predicted that the F576E mutant changed the secondary structure to a totally helical conformation in the region of the third intracellular and sixth transmembrane domain. In contrast, the F576G, F576I, and F576Y mutants were predicted to change the helical conformation in the region to an extended conformation. In expression studies, mutations of Phe576 produced functional changes in cAMP and inositol phosphate (IP) signaling, and human CG (hCG) binding. Mutations predicted to cause an extended conformation exhibited two functional patterns: first, constitutively activating in cAMP signaling without changes in IP signaling or hCG binding (F576I and F576G), and second, constitutively activating in cAMP signaling with decreased hCG-induced cAMP and IP signaling and with both higher affinity and lower capacity of hCG binding (F576Y). The mutation predicted to cause a totally helical conformation resulted in no cAMP response and a minimal IP response to hCG stimulation, with negligible hCG binding (F576E). These data suggest that the common change induced by the F576I, F576G, and F576Y mutations to an extended conformation on the third cytoplasmic loop and sixth transmembrane domain of the LH/CGR results in increased Gs coupling and activation of adenylyl cyclase. The F576Y mutation appears to have an additional effect, beyond a modification in receptor conformation, that leads to higher affinity and lower capacity of hCG binding, as well as altered Gq coupling and phospholipase C activation. The F576E mutation has a distinct and different impact on receptor conformation, which leads to negligible hCG binding and minimal function; however, the F576E mutation may provide a clue to understanding the receptor mutations that result in loss of function and pseudohermaphroditism. We conclude that Phe576 plays an important role in the human LH/CGR with respect to receptor conformation, Gs coupling, and cAMP signaling consistent with predictions from mutations associated with male-limited precocious puberty.

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, and testosterone secretion before the onset of male puberty.

To investigate hormonal change before the onset of male puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone hourly for 24 h. Forty-six boys (32 prepubertal and 14 pubertal) of short stature, between 4.4-19.3 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone was measured using high sensitivity RIA capable of detecting a testosterone concentration of 0.01 ng/mL. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 4-5 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated at early morning in all subjects. Mean 24-h LH, FSH, and testosterone concentrations of prepubertal subjects who did not attain puberty for at least 3 yr were 0.10 U/L, 0.63 U/L, and 0.06 ng/mL, respectively, whereas those of prepubertal subjects who attained puberty within 1 yr (0.54 U/L, 1.68 U/L, and 0.10 ng/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, and testosterone concentrations increased with developing puberty. All of the 46 subjects showed positive cross-correlation between the LH and testosterone time series. The mean lag time from the LH to the testosterone time series in the prepubertal subjects who attained puberty within 1 yr (4.7 +/- 2.4 h, mean +/- SD) was shorter than that in the prepubertal subjects who attained puberty after at least 3 yr (7.3 +/- 2.2 h). This lag time decreased with developing puberty, plateauing at 1.4 +/- 0.9 h at midpuberty. Thus, the diurnal rhythms of LH, FSH, and testosterone already exist at 4-5 yr of age; serum LH, FSH, and testosterone levels increase before the onset of puberty; and a time delay is observed between the LH and testosterone time series that decreases before the onset of puberty.

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol secretion before the onset of female puberty in short children.

To investigate hormonal changes before the onset of female puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone and estradiol hourly for 24 h. Seventeen girls (13 prepubertal and 4 early pubertal) of short stature, from 5.1-11.4 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone and estradiol were measured using a sensitivity RIA capable of detecting testosterone and estradiol concentrations of 10 and 2 pg/mL, respectively. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 5-6 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated in the early morning in all subjects. The serum estradiol concentration was elevated in the early morning in 4 of 13 prepubertal subjects and all 4 early pubertal subjects. The diurnal pattern of the serum estradiol concentration was similar to that of the serum testosterone concentration. Mean 24-h LH and testosterone concentrations in prepubertal subjects who did not attain puberty for at least 1 yr were 0.07 U/L and 65 pg/mL, respectively, whereas those in prepubertal subjects who attained puberty within 1 yr (0.14 U/L and 106 pg/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, testosterone, and estradiol concentrations increased with the onset of puberty. In conclusion, the diurnal rhythms of LH, FSH, and testosterone already exist at 5-6 yr of age, and serum LH and testosterone levels increase before the onset of puberty. These results suggest that preparation for the onset of female puberty may begin in 5- to 6-yr-old girls.

A sporadic case of male-limited precocious puberty has the same constitutively activating point mutation in luteinizing hormone/choriogonadotropin receptor gene as familial cases.

Familial male-limited precocious puberty (FMPP) is an autosomal dominant disorder characterized by marked elevation of serum testosterone despite low levels of gonadotropin. Recently, a single point mutation in the LH/hCG receptor (LH/CGR) gene was found in FMPP families that constitutively activates the LH/CGR, causing Leydig cell activation and precocious puberty. Among the Japanese population, only four sporadic cases of male-limited precocious puberty have been reported. In the current study, we examined one of the four reported Japanese patients with sporadic male-limited precocious puberty and found the same mutation as that in the FMPP families. Genomic DNA was isolated, and the polymerase chain reaction (PCR) was performed to amplify a fragment of LH/CGR DNA encoding amino acid residues that include transmembrane helixes 5 and 6. Sequencing of the PCR products revealed a heterozygous adenosine-guanine transition at nucleotide 1733 in codon 578. The mutation encodes an aspartic acid578-glycine substitution in transmembrane helix 6. The mutant LH/CGR, created by site-directed mutagenesis in vitro, exhibited constitutively higher cAMP levels in transfected COS-7 cells than the wild-type LH/CGR, as described previously; however, basal inositol phosphate levels were not increased by transfection with complementary DNA for the mutant receptor. The concentration and affinity of [125I]hCG-binding sites were similar in cells transfected with the mutant and wild-type LH/CGR complementary DNAs, indicating that the mutant did not alter the production of receptor or its ability to bind human LH/CG. The sporadic occurrence of this case was confirmed by further studies. The mutation creates a recognition site for the restriction endonuclease MspI. Restriction digestion was positive for the mutant not digested by MspI, indicating that the patient's mutant allele was not inherited from his parents. DNA analysis of the patient and the parents, using microsatellite repeat markers, was compatible with biological paternity and maternity. We conclude that the aspartic acid578-->glycine mutation in the LH/CGR has arisen in the Japanese population and is the cause of a sporadic case of male-limited precocious puberty.

Developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late prepuberty in boys.

To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume, <3 mL for at least 3 succeeding yr) and late prepuberty (genital stage I-C: bone age, 8.7 +/- 1.8 yr; testis volume, <3 mL for up to 1 yr thereafter; P: = 0.00019), which indicates the acquisition of more regular LH release patterns in late prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 +/- 1.0 yr; testis volume, 2.8 +/- 0.4 mL). The LH secretory process was more disorderly in mid- and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P: < 10(-)(7)), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the theoretically related bivariate cross-ApEn statistic disclosed maximal 2-hormone synchrony for LH and testosterone secretion in genital stage II (P: = 0.031), with relative deterioration of coordinate LH and testosterone release patterns both before and after. LH and FSH release became maximally synchronous at the end of prepuberty (genital stage I-C; P: = 0.029), and FSH and testosterone synchrony peaked in pubertal stage III (P: = 0.037). As mean 24-h serum concentrations of LH, FSH, and testosterone rose transpubertally by 35-fold (LH), 68-fold (FSH), and 70-fold (testosterone), respectively, we infer that pubertal developmental stage per se rather than level of hormone output dictates coordinate GnRH-LH/FSH-testosterone secretion. In summary, in eugonadal boys, the regularity of 24-h LH and testosterone secretory patterns undergoes well defined pubertal stage-specific control. No sexually developmentally delimited regulation is inferable for FSH. The concept of temporally biphasic puberty-dependent variations in neurohormone secretory regularity contrasts with the unidirectional rise in daily hormone output. Accordingly, we infer that late prepuberty and early puberty (Tanner genital stages IC and II) embody a physiologically unique sexual developmental window, marked by transiently enhanced LH and testosterone feedback stability in boys. Whether analogous plasticity of hypothalamo-pituitary-gonadal interactions unfolds during female adolescence is not known.

Prenatal diagnosis of metachromatic leukodystrophy: a diagnosis by amniotic fluid and its confirmation.

Late infantile metachromatic leukodystrophy (MLD) was successfully diagnosed in utero by demonstrating the absence of arylsulfatase-A in amniotic fluid using diethylaminoethyl-Sepharose column chromatography. Diagnosis by amniotic fluid using an ion-exchange column is more rapid and reproducible as compared with those reported previously. The diagnosis was confirmed by the absence of arylsulfatase-A in fetal brain, liver, and kidney tissues as well as by the marked accumulation of sulfatide in kidney. The kidney is the most appropriate organ for the demonstration of sulfatide accumulation in fetal tissues in MLD.

Kabuki make-up syndrome is not caused by microdeletion close to the van der Woude syndrome critical region at 1q32-q41.

We reported on a 5-year-old Japanese girl with clinical manifestations of Kabuki make-up syndrome (KMS) and van der Woude syndrome (VWS). Since the concurrence of the two syndromes is known in four patients, including ours, it suggests a common cause. Assuming that the association of the two syndromes was caused by a microdeletion involving the putative KMS/VWS genes, we carried out fluorescence in situ hybridization and microsatellite analyses using PAC clones and dinucleotide repeat markers spanning the VWS1 critical region at 1q32-q41. No deletion was detected at the VWS1 critical region.

Intrafamilial phenotypic variability in Engelmann disease (ED): are ED and Ribbing disease the same entity?

We report on clinical and radiologic manifestations in a 3-generation Japanese family with Engelmann disease (ED) or progressive diaphyseal dysplasia. A large variation of phenotype was remarkable among 12 affected family members. Of the 12 patients, 7 had full manifestations of ED, such as bilateral, symmetrical diaphyseal sclerosis of long bones with myopathy and limb pain, whereas the other 5 exhibited only segmental (rhizomelic and/or mesomelic) involvement and asymmetric diaphyseal sclerosis without any clinical symptoms. The phenotype of the latter group of patients resembled Ribbing disease (RD). We propose that ED and RD represent phenotypic variation of the same disorder.

Complex glycerol kinase deficiency: molecular-genetic, cytogenetic, and clinical studies of five Japanese patients.

Five male Japanese patients with complex glycerol kinase deficiency (CGKD) and their relatives were studied clinically, cytogenetically, and molecular-genetically. All patients had muscular dystrophy or muscle weakness, mental retardation, congenital adrenal hypoplasia, and glycerol kinase deficiency. High-resolution GTG-banded chromosomes showed a microdeletion in the Xp21 region in all four patients examined and in all five mothers. Southern hybridizations, after digestions by restriction endonucleases, with various cloned DNAs (D2, 99-6, B24, C7, L1-4, cDMD13-14, J66-HI, P20, J-Bir, ERT87-30, ERT87-15, ERT87-8, ERT87-1, XJ-1.1, 754, cx5.7, and OTC-1) that are located around Xp21 also showed a deletion in the genome of all patients and mothers. Although the deletion differed in size among patients, a segment commonly absent was located between the genomic sequences corresponding to L1-4 and cDMD13-14. This finding indicated that the gene coding for glycerol kinase (GK) is located within this segment. A comparison of the clinical manifestations of the present five patients and reported CGKD or Duchenne muscular dystrophy (DMD) patients with DNA deletion suggests the existence of a certain gene responsible for gonadotropin deficiency (GTD). The result of the present study and results of previous studies suggest that genes for ornithine transcarbamylase (OTC), DMD, and GK and putative genes responsible for congenital adrenal hypoplasia (AHC) and GTD are arranged from telomere to centromere as pter--GTD--AHC--GK--DMD--OTC--cen.

Effects of the two somatostatin variants somatostatin-14 and [Pro2, Met13]somatostatin-14 on receptor binding, adenylyl cyclase activity and growth hormone release from the frog pituitary.

Two isoforms of somatostatin from frog brain have been recently characterized, namely somatostatin-14 (SS1) and [Pro2, Met13]somatostatin-14 (SS2). The genes encoding for the precursors of these two somatostatin variants are expressed in hypothalamic nuclei involved in the control of the frog pituitary. The aim of the present study was to investigate the effect of SS1 and SS2 on adenohypophysial cells. Autoradiographic studies using [125I-Tyr, D-Trp8] SS1 as a radioligand revealed that somatostatin binding sites are evenly distributed in the frog pars distalis. The SS2 variant was significantly (P < 0.01) more potent than SS1 in competing with the radioligand (IC50= 1.2 +/- 0.2 and 5.6 +/- 0.6 nM, respectively). Both SS1 and SS2 induced a modest but significant reduction in cAMP formation in dispersed distal lobe cells but did not affect spontaneous growth hormone (GH) release. Synthetic human GRF (hGRF) induced a significant increase in cAMP accumulation and GH release in this system. Both SS1 and SS2 inhibited the stimulatory effects of hGRF on cAMP formation and GH secretion. These data show that the SS1 and SS2 variants can regulate adenohypophysial functions. The fact that GH cells are exclusively located in the dorsal area of the frog adenohypophysis, while somatostatin receptors are present throughout the pars distalis, indicates that the two somatostatin isoforms may control the secretion of pituitary hormones additional to GH in amphibians.

Suppression of hepatic gluconeogenesis in long-term Troglitazone treated diabetic KK and C57BL/KsJ-db/db mice.

The orally effective antidiabetic agent Troglitazone (CS-045) exerts hypoglycemic effects in various insulin-resistant obese and/or diabetic animals. Since increased hepatic gluconeogenesis is a major cause of hyperglycemia in these diabetic animals, we evaluated the effect of long-term Troglitazone treatment on hepatic gluconeogenesis. Troglitazone was administered for 7 days to normal ddY mice, diabetic KK mice, diabetic C57BL/KsJ-db/db mice, and its heterozygote, db/+ mice, as a 0.1% or 0.2% food admixture. Troglitazone significantly decreased plasma glucose in diabetic KK and db/db mice, but not in normal ddY and db/+ mice. 14C incorporation into blood glucose from NaH14CO3 was measured to assess hepatic gluconeogenesis in diabetic KK and normal ddY mice. Hepatic gluconeogenesis was significantly increased in diabetic KK mice (P < .01) as compared with normal mice, and was significantly suppressed (P < .05) after 7 days of Troglitazone treatment (approximately 200 mg/kg/d). Glucose-6-phosphate (G6P) and fructose-6-phosphate (F6P) were significantly decreased but fructose-1,6-bisphosphate (FBP) was not significantly increased in the liver of diabetic db/db mice treated with Troglitazone for 7 days (approximately 80 mg/kg/d) as compared with control db/db mice. These changes in G6P, F6P, and FBP corresponded with the activity of fructose-1,6-bisphosphatase (Fru-1,6P2ase) and 6-phosphofructo-1-kinase (6-PF-1K), which determined the content of F6P and FBP. Namely, Fru-1,6P2ase was significantly decreased in Troglitazone-treated db/db mice as compared with control mice, whereas 6-PF-1K activity was not affected by Troglitazone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effect of troglitazone on glucose metabolism in the absence or presence of insulin in perfused rat hindlimb.

Troglitazone (CS-045) is a new type of antidiabetic agent that decreases plasma glucose by enhancing insulin action in insulin-resistant diabetic animals and non-insulin-dependent diabetes mellitus (NIDDM) patients. To examine the direct effect of troglitazone on glucose metabolism and insulin action in skeletal muscle, we infused troglitazone solution into perfused rat hindlimbs in the presence of 6 mmol/L glucose and in the absence or presence of insulin. In the absence of insulin, even 50 mumol/L troglitazone did not elicit glucose uptake. Troglitazone did increase lactate and pyruvate release at concentrations of 20 mumol/L and higher; however, it decreased the ratio of lactate to pyruvate (L/P ratio) and increased oxygen consumption at concentrations higher than 5 and 20 mumol/L, respectively. In hindlimb muscle, 20 mumol/L troglitazone decreased glycogen content without changing fructose 2,6-bisphosphate (F2,6P2) content in the absence of insulin. Insulin infusion with 250 microU/mL obtained half-maximal effects, causing a 2.8-fold increase in glucose uptake and a 1.5-fold increase in lactate and pyruvate release. When 20 mumol/L troglitazone was infused for 30 minutes together with 250 microU/mL insulin, insulin-induced glucose uptake significantly increased 30 minutes after troglitazone infusion, and this increase was further augmented after withdrawal of troglitazone. In insulin plus troglitazone infusion at 30 minutes after troglitazone removal, glycogen content in hindlimb muscle was significantly decreased compared with that obtained with insulin infusion alone. In summary, in the absence of insulin, troglitazone does not elicit glucose uptake, but causes an increase in glycolysis accompanied by a decrease in muscle glycogen content and L/P ratio and an increase in oxygen consumption. In the presence of insulin, troglitazone increases insulin-induced glucose uptake, and this increase is further augmented after troglitazone removal. Addition of troglitazone to insulin infusion decreased the glycogen content in hindlimb muscle. This decrease in muscle glycogen content may trigger an enhancement of insulin-induced glucose uptake similar to that observed during muscle contraction or epinephrine treatment.