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Biomedical subjects

Z Laron

Publications and source records attributed to Z Laron.

At least 325 records · Page 18Linked to original sources
PubMed1976

Comparative HGH response to i.v. glucagon and i.v. arginine stimulation tests in children and adolescents.

Thirty-seven children and adolescents of several diagnostic entitites (constitutional growth retardation, diabetes mellitus and pituitary insufficiency) were tested with an i.v. bolus injection of glucagon for plasma human growth hormone (HGH) response. Most of the subjects were also tested for the same purpose by the arginine stimulation test, and the data were compared. It was found that i.v. glucagon is a potent stimulus of human growth hormone release. The HGH is released in two peaks, the first one occuring within 30 min, most probably by a direct effect. The second peak occurs after 120 min, most probably as a secondary effect caused by the drop in blood glucose after its initial rise, which is induced by glucagon. The peak concentrations of HGH induced by glucagon, were very similar to those provoked by i.v. arginine in the same subjects.

Adolescent↗
PubMed1976

Response of plasma LH and FSH to synthetic LH-RH in children at various pubertal stages.

Fifty normal boys and 47 normal girls, aged 5 to 18 years, underwent a standard luteinizing hormone-releasing hormone (LH-RH) test (50 mug/sq m by rapid intravenous injection), and the plasma levels of LH and follicle-stimulating hormone (FSH) were determined. The results were analyzed separately according to the pubertal stages for each sex. A wide range of distribution of the individual measurements of the plasma gonadotropins throughout the LH-RH tests was found, but the mean values of the basal and peak levels showed a definite pattern for each sex at the different pubertal stages. Of particular interest was the sharp rise in basal plasma FSH level and its marked response to LH-RH in girls at the onset of puberty. The girls at this stage had the highest basal and peak FSH levels obtained at any pubertal stage in both sexes. It is concluded that the establishment of norms of LH and FSH response to a standard dose of LH-RH will be useful in evaluating normal and abnormal pubertal states in both sexes.

Adolescent↗
PubMed1976

The influence of oral glucose loading on the insulin response to i.v. glucagon in children and adolescents.

Fourteen children and adolescents with slight constitutional growth retardation (12 males and two females) aged from 7 1/2 to 18 1/2 yr underwent an oral glucose tolerance test (OGTT 1.75 g/Kg followed at 180 min by an i.v. glucagon injection (0.03 mg/Kg). On a separate occasion these children underwent a simple i.v. glucagon test. Comparing the glucose and insulin response in the two glucagon tests for each child we found that whereas in the single test the blood glucose rose slowly with a peak at 30 min, in the combined test the peak was at 5 min. The mean peak values were similar (129 and 121 mg/100 ml). The mean peak insulin response in the single test was 70 muU/ml (at 2 min) as compared to 253 muU/ml (at 2 min) in the combined test. Our studies provide further evidence for a direct effect of glucagon on insulin release and that glucose preloading augments this effect, without relation to the concomitant blood glucose concentrations.

Adolescent↗
PubMed1976

The effect of repeated injections of synthetic luteinizing hormone-releasing hormone on the response of plasma luteinizing hormone and follicle-stimulating hormone in young hypogonadotropic-hypogonadal patients.

Sixteen patients, ages 14 to 18, eleven with isolated gonadotropin deficiency and five with sporadic multiple pituitary hormone deficiency, were subjected to a course of five daily intramuscular injections of synthetic luteinizing hormone releasing hormone (LH-RH), 100 mug/day. Before and after the course of intramuscular injections, a rapid LH-RH test (by a one-bolus intravenous injection of 50 mug/sq m) was performed and the responses of plasma LH and follicle-stimulating hormone were measured by a radioimmunoassay method. The patients could be divided into three groups according to the response of the plasma LH to the second LH-RH test: group A, five patients with a significantly higher response of plasma LH to the second LH-RH test: group B, nine patients with a less significantly higher response of the plasma LH to the second LH-RH test; and group C, two patients with very low or no response to either stimulation used in this study. The patients in the three groups may represent different etiologic entities, namely that of a separate hypothalamic lesion, a "mixed" pituitary and hypothalamic lesion, and a "pure" pituitary lesion, respectively. It is concluded that the proposed procedure provides a useful tool for discriminating etiologic groups in patients with abnormal gonadotropic secretion. Recognition of tertiary hypogonadism (primary, pure, hypothalamic gonadotropin-releasing hormone deficiency) is of practical importance in selecting those patients who can benefit from long standing LH-RH therapy.

Adolescent↗
PubMed1976

Cyproterone acetate in treatment of precocious puberty.

Twenty-nine children (23 girls, 6 boys) with precocious puberty were treated with cyproterone acetate for various periods of time ranging from 6 months to 3 years 4 months. They received an oral dose ranging from 70-150 mg/m2 per day, or an intramuscular depot injection once a fortnight or once a month at a dose ranging from 107-230 mg/m2. Both forms of therapy were found to suppress the signs of sexual maturation, but the oral form proved to be superior. Only the younger patients with a bone age under 11 years showed a beneficial effect upon linear growth and bone maturation. No side effects were noted, but additional advantageous effects upon behaviour and sociability were. It is concluded that at present cyproterone acetate by mouth is the drug of choice in the treatment of precocious puberty. The treatment should be initiated as early as possible to attain maximum benefit.

Administration, Oral↗
PubMed1976

Correlation between plasma growth hormone and insulin and blood glucose concentrations in premature infants.

Plasma growth hormone, insulin and blood glucose levels were measured longitudinally during the first 60 days of life in 21 premature infants (8 males and 13 females) born between the 6th and 8th month of gestation. When these variables were related to age it was found that insulin and glucose, which are lower than in the prepubertal children and adults, rise simultaneously. Whereas growth hormone, which is higher than in older prepubertal children, decreases during the first 2 weeks of life. The decrease in growth hormone continues during the first 2 months of life, in contrast to the increases in insulin and glucose which do not persist in as long a period.

Blood Glucose↗
PubMed1976

Heterogeneity of pituitary and endogenous plasma human growth hormone from fetuses, premature and full-term newborns.

Fetal and adult human growth hormone (HGH) extract from human pituitaries as well as plasma from premature and full-term newborns and children were submitted to chromatography on Sephadex G-75 and the immunoreactive HGH (IRHGH) in the elution fractions was determined quantitatively by radioimmunoassay. Three fractions of IRHGH could be differentiated according to the elution pattern: 'big-big', 'big' and 'little' IRHGH. In fetal pituitary extract only 'big-big' and 'little' IRHGH were found, whereas in adult pituitary extract all three forms of IRHGH were present. In the plasma samples studied no 'big-big' form was found; only 'big' and 'little' IRHGH appeared. In addition, plasma samples of premature newborns had a smaller proportion of the 'big' IRHGH than did those of the full-term newborns and older children.

Fetus↗
PubMed1976

Receptor-active growth hormone in Laron dwarfism.

The hepatic radioreceptor assay for hGH has been applied to the detection of hGH in the sera of patients with high growth hormone dwarfism (Laron dwarfism). Substantial quantities of receptor-active hGH were found in the sera of all 7 patients studied. In one patient, arginine infusion elicited a prompt increase in both immunoactive and receptor-active hGH. These observations suggest that circulating hGH in Laron dwarfism is biologically active and support the concept that the disease may be caused by a generalized defect in hGH receptors.

Arginine↗
PubMed1976

Response to LH-RH and HCG in two brothers with the Reifenstein syndrome.

Two brothers with Reifenstein syndrome underwent LH-RH and HCG tests at various ages ranging from 13 to 17 years. We found that at age 13 the plasma LH and FSH response to one LH-RH injection was normal. After the age of 14, the basal plasma concentration of LH and FSH and their response to LH-RH became elevated. Concomitantly the plasma testosterone levels rose to abnormal levels. These findings are compatible with progressive development of primary gonadal dysfunction and with peripheral insensitivity to testosterone.

17-Ketosteroids↗
PubMed1976

Intermittent treatment with human growth hormone (GH) in isolated GH deficiency and in multiple pituitary hormone deficiencies.

The results of intermittent GH treatment of 3-7 1/2 years duration in seven patients with isolated GH deficiency (IGHD) and five patients with multiple pituitary hormone deficiencies (MPHD) are presented. This therapeutic schedule was found to be comparably effective to those using a continuous-administration schedule. In contradistinction to the findings obtained with the latter, there was no progressive decline in growth velocity. The patients with IGHD were found to respond better than the patients with MPHD both in the first course as well as in consequent courses. In the intervals between courses, the growth velocity was less than in the pretreatment period in both groups. It is concluded that optimal results can be obtained by instituting an initial course of continuous treatment of 1 year's duration for the IGHD patients and of 2 years' duration for the MPHD patients, followed by an intermittent therapeutic schedule. This regime not only leads to the same growth achievement obtained with long-term continuous administration of GH but allows conservation of supplies of this very scarce hormone.

Adolescent↗
PubMed1976

Human chorionic gonadotropin stimulation of Leydig cell function in puberty. Comparison of testosterone response in plasma and urine.

The plasma and urinary testosterone response to one i.m. injection of 5,000 IU human chorionic gonadotropin (HCG) was tested in 45 children and adolescents of several diagnostic entities: testosterone was measured before the injection and on the second, fourth and sixth days thereafter. It was found that there was a better correlation between the testosterone concentrations and the different pubertal stages than between testosterone concentration and either chronological or skeletal age. In the children with normal pubertal development, there was a slight rise in basal testosterone concentration with the progression of the pubertal stages. HCG caused a rise in plasma and urinary testosterone: this response was more marked in pubertal stages 4 and 5. The urinary response was variable whereas the changes in plasma testosterone concentration were more constant. In children and adolescents with primary or secondary hypogonadism, the basal levels of testosterone were low or undetectable and there was only a slight response to the single dose of HCG. It was concluded that a single i.m. injection of 5,000 IU HCG and the determination of plasma testosterone before, and two and four days after injection is a useful screening test for Leydig cell function.

Adolescent↗
PubMed1976

Glucose and insulin responses to an oral glucose load in normal children and adolescents in Israel.

Sixty-three normal, healthy children and adolescents (39 males and 24 females) ranging in age from 2 to 20 years, were given a standard oral glucose tolerance test. A tendency to higher blood glucose levels and a statistically significant increase in insulin levels were found in the older age group in response to the glucose load. The older age group showed a significantly higher response of both glucose and insulin when separate percentile curves for prepubertal and pubertal boys and girls were constructed. No statistical differences were found between the sexes. Our findings demonstrate the necessity of applying norms for the oral glucose tolerance test according to age, particularly with respect to insulin values. The possibility of additional differences in response among various populations, as apparent from a comparison with the results of several other investigators, requires further study.

Adolescent↗
PubMed1976

Height and weight of children born to mothers with diabetes mellitus.

Height and weight measurements in a group of 55 children born to mothers with juvenile, adult-onset or gestational diabetes mellitus showed that the children born to parents of European or American origin were taller than average. The talles children were those born to mothers with juvenile diabetes mellitus. The distribution of weight-height indexes followed a normal pattern.

Adolescent↗
PubMed1976

Increased densities and calcifications in the finger bones of children.

A feature of irregular calcifications and increased densities in the metaphyseal region of the fingers of the hand in adolescent children, occurring mostly in males, is described. These changes become evident at puberty and disappear with the closure of the epiphyses. The etiology of this feature does not appear to be related to a specific hormone. It may be the result of an imbalance between those hormones which cause the pubertal spurt, possibly combined with an irregularity of testosterone secretion.

Adolescent↗