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Biomedical subjects

Z Laron

Publications and source records attributed to Z Laron.

At least 235 records · Page 13Linked to original sources
PubMed1983

Effect of human growth hormone therapy on penile and testicular size in boys with isolated growth hormone deficiency: first year of treatment.

The response of genital and gonadal growth during the first year of treatment with human growth hormone (hGH) was studied in 20 boys with isolated growth hormone deficiency (IGHD) (11 of hereditary origin and 9 sporadic cases). Prior to hGH treatment, 13 of the 15 prepubertal boys had a penis length below the normal mean, 3 of which were more than 2 SDS below the mean. The boys with hereditary IGHD had a greater deficit in penile size than did the sporadic cases. hGH treatment improved the penile length in all but two boys aged 14 and 15 yr, and led to growth up to normal size in the three boys with very small penises. Three of the hereditary IGHD patients had subnormal testes and all of the other prepubertal boys had a testicular volume in the normal range. hGH treatment increased testicular size, particularly in the prepubertal boys. Of three additional untreated adults with IGHD, one had a subnormal-size penis and two had penises of low-normal size. Our findings constitute further evidence that hGH deficiency is associated with decreased penile growth and, to some extent, decreased testicular size, and that hHG treatment improves the growth of the genitalia and gonads. Since these effects were also observed in prepuberty, it seems that not all the hGH or, rather, somatomedin effect on sex organs is androgen mediated.

Adolescent↗
PubMed1983

Histopathological features of the skin in hypopituitarism and Laron-type dwarfism.

Skin biopsies from children and adolescents with various syndromes of somatomedin deficiency revealed changes in structure and in distribution of the dermal elastin fibers as compared with a group of seven healthy control subjects. In 18 patients with isolated growth hormone deficiency (IGHD) and in 11 with multiple pituitary hormone deficiencies (MPHD), the number of elastin fibers was reduced; the individual fibers were shorter and slimmer than usual, and frequently arranged in groups dispersed in various directions. Skin biopsies from six patients with Laron-type dwarfism (LTD) revealed mostly thickened elastin fibers, frequently arranged in irregular bundles, but the number of elastin fibers was normal in prepubertal patients and reduced only in postpubertal patients. The reduction of elastin fibers in these patients was less prominent than in IGHD. The finding of more numerous elastin fibers in LTD than in IGHD is suggestive of a direct nonsomatomedin-mediated effect of human growth hormone on skin elastogenesis.

Adolescent↗
PubMed1982

A comparative study of the effect of oestrogen substitution therapy on breast development in girls with hypo- and hypergonadotrophic hypogonadism.

During treatment of girls with oestrogen deficiency we observed different patterns of breast development in response to therapy. The forty-five girls studied fell into four groups: Group A, gonadal dysgenesis; Group B, isolated gonadotrophin deficiency; Group C, multiple pituitary hormone deficiencies; Group D, congenital adrenal hyperplasia (17-alpha-hydroxylase deficiency). Treatment with oestrogen was given in an identical manner to all. In the patients with gonadal dysgenesis, in whom the hypothalamic-pituitary function was normal, treatment led to full breast development. In isolated gonadotrophin deficiency and multiple pituitary hormone deficiency breast development was incomplete even after 3 years or more of oestrogen treatment. The conspicuous difference in the hormonal status is that the latter two groups lack gonadotrophins, while in gonadal dysgenesis these hormones are grossly elevated. Our conclusion is that gonadotrophins play an important role in mammary gland development, a finding not previously described. In the girl with 17-alpha-hydroxylase deficiency we observed that cortisol was necessary, in addition to sex hormones, for normal breast development.

Adolescent↗
PubMed1982

Adrenocortical function in children with precocious sexual development during treatment with cyproterone acetate.

Adrenal function was studied in thirty-two children with precocious sexual development who were being treated with cyproterone acetate (CPA) at doses ranging from 68 to 175 mg. m2. day for periods lasting from 2 to 79 months. In eighteen children the adrenocortical function evaluation was made before and during CPA treatment. In these eighteen patients, the mean basal plasma cortisol level during the morning hours was 11.2 +/- 4.6 micrograms/dl (m +/- SD) before treatment and fell significantly to 7.2 +/- 4.1 micrograms/dl (P less than 0.02) during therapy. In fifteen patients tested during insulin hypoglycaemia the cortisol peak fell from 21.6 +/- 5.5 micrograms/dl before treatment to 16.7 +/- 6.8 micrograms/dl (P less than 0.05) during CPA therapy. There was a significant inverse correlation between this peak and the dose of CPA but no correlation was found between the cortisol response and duration of treatment. In eight of twenty patients tested, urinary free cortisol levels were undetectable during treatment. No change in basal plasma ACTH levels were demonstrated using standard radioimmunoassay techniques. In the patient receiving the highest dose of CPA and showing complete suppression of the adrenal axis, prolonged stimulation with ACTH-Depot demonstrated a responsive adrenal gland. Addition of a replacement dose of cortisol to the CPA treatment led to the rapid development of the typical signs of Cushing's syndrome. It was concluded that despite the evidence of adrenal suppression by CPA, cortisol supplementation is not necessary and may not even be contraindicated.

Adrenal Cortex↗
PubMed1982

Dynamics of basal pituitary gonadotropin secretion and responsiveness to LRH following estradiol benzoate in normal boys.

The influence of a single intramuscular injection of estradiol benzoate (E2B), 2.5-15 micrograms/kg, on the basal estradiol, LH and FSH and their response to LRH stimulation (50 micrograms/m2, i.v.) performed 20 h after E2B injection, was studied in 52 normal boys aged 6-16 9/12 years. The minimal effective dose of E2B was found to be 10 micrograms/kg. This same dose of E2B which increased plasma estradiol level from 15 +/- 8 to 22 +/- 15 pg/ml (mean +/- SD) at 20 h after the intramuscular injection, suppressed basal plasma LH and FSH and their response to LRH in the prepubertal (n = 12), early-pubertal (n = 12) and late-pubertal (n = 8) boys. It is suggested that the maturation of the hypothalamo-pituitary axis in boys during puberty is under the influence of endogenous estradiol.

Adolescent↗
PubMed1982

Dynamics of basal pituitary gonadotropin secretion and responsiveness to LRH following estradiol benzoate in normal girls.

The influence of a single intramuscular injection of estradiol benzoate (E2B), 2.5-15 micrograms/kg, on the basal plasma estradiol, LH and FSH and their response to LRH stimulation (50 micrograms/m2, i.v.) performed 20 h after E2B injection, was studied in 50 normal girls aged 6-17 years. It was found that the minimal dose of E2B which caused a significant change in the basal and/or LRH stimulated LH and FSH levels was 10 micrograms/kg. This dose increased plasma estradiol level by 10-35 pg/ml, i.e. still within the normal range for the appropriate pubertal stage of the subjects. The same dose of E2B significantly suppressed the basal FSH level in most of the prepubertal (n = 8), early-pubertal (n = 9) and late-pubertal (n = 14) girls and the FSH response to LRH in most prepubertal girls. The basal LH was suppressed in most pre- and early-pubertal girls, but increased significantly in 50% of the late-pubertal girls. The LH response to LRH was significantly increased in most of the girls at all pubertal stages. It is suggested that endogenous estradiol is an important mediator in the maturation of the hypothalamo-pituitary axis in girls from mid-puberty onwards, and that the low physiological level of estradiol present in adolescence is sufficient to induce a gradual increase in pituitary sensitivity to LRH and a positive hypothalamo-pituitary feedback.

Adolescent↗
PubMed1982

Effect of anorexia nervosa on gonadotrophin secretion in a patient with gonadal dysgenesis.

The 11th documented concurrence of anorexia nervosa (AN) and XO-gonadal dysgenesis (GD) is reported. This is the first endocrine study of such a disease combination. The patient, a 15-year-old girl, has been followed since early childhood and comprehensive endocrinological investigation were performed before, during and after the episode of AN. The dynamic changes in the thyroid and pituitary hormones were in concordance with those already observed by us as well as by others in patients with AN. The most remarkable observations concerned the gonadotrophin secretion: during the anorectic episode basal levels and peak responses to LRH and both LH and FSH were seen to decrease from the hypergonadotrophic range to the normal prepubertal range whereas after recovery from AN and regain of weight these rose back to castration levels. AN would seem to be the only condition yet known able to abolish temporarily the hypergonadotrophic state of GD, a fact favouring the hypothesis that AN is associated with a reversible hypothalamic dysfunction. It is assumed that this disturbance is due to nutritional as well as to psychological factors. The significance of the coexistence of AN and GD is discussed and it is suggested that psychological factors in GD may be implicated in this association.

Adolescent↗
PubMed1982

Late-onset type of 21-hydroxylase deficiency in childhood.

It was recently proposed that congenital and late-onset 21-hydroxylase deficiency are caused by two distinct recessive allelic genes. Although both genes are associated with the HLA system, only the late-onset type was found to be linked with the antigens B14 and DR1. Biochemical and immunological studies were conducted in two families with children suffering from 21-hydroxylase deficiency of postnatal onset. In the first family, of Jewish Ashkenazic origin, a 2 1/2-yr-old girl presenting with clitoromegaly was found to be homozygous for the antigens B14 and DR1. In the second family, of Arabic origin, all the children, their parents and a paternal aunt were clinically and/or biochemically affected, carrying the B14, but not the DR1 antigen on one or both HLA haplotypes. These data suggest that some cases of simple virilizing 21-hydroxylase deficiency in childhood are related to the late-onset type of 21-hydroxylase deficiency.

Adrenal Hyperplasia, Congenital↗
PubMed1981

D-TRP5-analogue of luteinising hormone releasing hormone in combination with cyproterone acetate to treat precocious puberty.

A 6-year-old girl with central (true) precocious puberty was successfully treated with a combination of the luteinising hormone releasing hormone analogue (D-Trp6)-LH-RH and cyproterone acetate. This treatment led to an almost complete arrest of gonadotrophin and oestrogen secretion, induced regression of pubertal signs, and markedly slowed bone maturation. It is suggested that the paradoxical refractoriness of the gonadotrophic and gonadal cells induced by long-term treatment with LH-RH agonists can be exploited in the treatment of precocious puberty.

Bone Development↗