Factors determining serum-insulin response in a population sample

Summary Serum-insulin levels were measured in 1770 subjects one hour after a 50 g glucose load. Multiple regression analyses reveal that a substantial proportion of the variability of log₁₀ serum-insulin can be attributed to significant independent effect of blood-sugar, age, the food-interval, sex, parameters of body size, and scserum uric acid. Females have significantly higher levels of serum-insulin than males One-hour blood-sugar levels exceeding 160 nag/100 ml are associated with declining insulin levels. An independent association of increasing age with increasing serum-insulin is evident at 50 years and over. The findings provide strong support for the biological significance of serum-immunoreactive insulin.

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Einfluß verschiedener Faktoren auf die Seruminsulinausschüttung bei einer Reihenuntersuchung

Zusammenfassung Die Seruminsulinspiegel 1 Std nach oraler Verabreichung von 50 g Glucose wurden bei 1770 Probanden bestimmt. Eine multiple Regressionsanalyse der Zehnerlogarithmuswerte für die Seruminsulinkonzentrationen ergab, daß ein beträchtlicher Teil der Variationsbreite durch signifikante und von einander unabhängige Einflüsse des Blutzuckers, des Alters, der Intervalle zwischen den Mahlzeiten, des Geschlechtes, des Körpergewichtes und der Harnsäure bedingt ist. Frauen wiesen significant höhere Insulinwerte als Männer auf. Häufig waren 1 Std Blutzuckerwerte über 160 mg% mit sinkenden Insulinspiegeln gekoppelt. Bei über 50 jährigen stiegen mit zunehmendem Alter auch die Insulinwerte an. Die Befunde stützen die Annahme, daß den immunologisch gemessenen Seruminsulinspiegeln biologische Bedeutung zukommt.

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Facteurs déterminant la réponse de Vinsuline sérique dans un échantillon de population

Résumé Les taux d'insuline sérique ont été mesurés chez 1770 sujets une heure après une charge en glucose de 50 g. Des analyses de régression multiple révèlent qu'une proportion considérable de la variabilité du log₁₀ de l'insuline sérique revient de façon significative aux effets indépendants entre eux de la glycémie, de l'âge, de l'intervalle entre les repas, du sexe, des paramètres de la taille corporelle et de l'acide urique sérique. Les femmes ont des niveaux d'insuline sérique significativement plus élevés que les hommes. Les taux de la glycémie une heure après, dépassant 160 mg/100 ml sont associés à une défaillance des taux d'insuline. Une association indépendante entre l'augmentation de l'âge et l'augmentation de l'insuline sérique est évidente à 50 ans et plus. Ces résultats apportent un argument solide pour l'importance biologique de l'insuline immunoréactive du sérum.

     

Purified murine hematopoietic stem cells function longer on nonirradiated W41/Wv than on +/+ irradiated stroma

Mouse bone marrow (BM) was separated into low-density, lineage- negative, wheat germ agglutinin-positive (WGA+), Rhodamine-123 bright (Rhbright) or dim (Rhdim) cells to obtain populations that were highly enriched for committed progenitors (Rhbright cells) or for more primitive stem cells (Rhdim). When 2,500 Rhbright or Rhdim cells were seeded onto 6-week-old irradiated (20 Gy) long-term BM cultures (LTBMC), the nonadherent cell production from Rhbright cells was transient and ended after 5 weeks. Production from Rhdim cells did not begin until week 3, peaked at week 5, and ended at week 8, when the irradiated stroma seemed to fail. Termination of cell production from Rhdim cells did not occur in nonirradiated LTBMC from W41/Wv mice. During peak nonadherent cell production, 25% to 30% of the cells in the nonirradiated LTBMC from W41/Wv mice had donor cell markers. Two approaches were tested to try to enhance the proportion or number of donor cells. Addition of Origen-HGF at the time of seeding Rhdim cells caused a nonspecific increase in both host and donor cell production, but a specific increase in production of donor cells was obtained by seeding the cultures at 2 weeks rather than 6 weeks. Limiting dilution of Rhdim cells gave the same frequency of wells producing cells on both irradiated +/+ and nonirradiated W41/Wv or W/Wv cultures.     

Discriminant analysis of data in ulcer and nonulcer populations

The purpose of this study was to assess whether consideration of age and body weight measurements improved discrimination between normal subjects and duodenal ulcer subjects using the maximal acid output test. Seventy-seven male volunteers were the normal group, and 155 patients with surgically proven duodenal ulcers were the ulcer group. We found that the ratio of maximal acid output to actual weight gave the best discrimination between the two groups. Using this ratio, there were 45 hypersecretors in the ulcer group, and only 1 false-positive among the normal subjects. A graphic method is described which employs the ratio of acid to weight and can correctly classify two-thirds of the ulcer group. The disadvantage of this method, however, is that one-third of the control group in our series were misclassified as hypersecretors; therefore, the clinician must consider history and barium meal findings as well as this evaluation of the subject.Deceased.     

The regulation of leptin gene expression in the C6 glioblastoma cell line

The hormone leptin is implicated in the regulation of appetite and body weight in rodents, primates and humans. We reported that the leptin gene (ob) is expressed in the brain, but the factors which control ob expression in the central nervous system are not known. We previously showed that brain-derived rat C6 glioblastoma cells express ob mRNA and protein. In the present study we examined the regulation of ob expression in C6 cells. Leptin and leptin receptor immunoreactivity was detected in C6 cells, suggesting a possible autocrine role for leptin. The identity of the leptin immunoreactivity (OB-ir) in C6 cells was confirmed by immunoprecipitation and Western blotting using two leptin specific polyclonal antibodies. Using RT-PCR analysis a product of the expected size for the short, but not the long, leptin receptor isoform was detected in C6 cells. Cells were maintained in serum-free (SF) media for 0-24 h in the presence of various regulators of leptin expression. Leptin mRNA levels were significantly higher in cells treated with dbcAMP (1 mM), IGF 1 (100 ng/ml) or insulin (5 microg/ml) compared to SF controls. In contrast, corticosterone (10(-7)M) reduced leptin mRNA. In the presence of dbcAMP, C6 cells undergo a dramatic alteration in morphology which is coincident with an apparent increase in the number of leptin-ir nuclei and an increase in leptin immunoreactivity. In contrast to C6 cells, glucocorticoids are reported to increase leptin levels in adipocytes/adipose tissue, while increases in intracellular cAMP levels are reported to reduce leptin levels. Overall, our in vitro data suggest that the regulation of leptin gene expression in C6 glioblastoma cells is different from that in adipocytes.