Correlative study of radioreceptor assay and radioimmunoassay of serum growth hormone in children: normal children and HGH-treated pituitary dwarfs

A sensitive and reproducible radioreceptor assay (RRA) for human growth hormone (HGH) is described. It allows the evaluation of HGH concentrations as low as 2 ng/ml. It has a limited cross-reactivity with human prolactin, which does not interfere at physiological levels in children. Comparison of the results with those of radioimmunoassay (RIA) showed no discrepancies in the serum of normal children before and after stimulation tests for GH (mean RRA/RIA ratio 1.03 +/- SEM 0.04, range 0.75 to 1.65) nor in the serum from hypopituitary dwarfs during the 12 h following an im injection of 6 mg of HGH (mean RRA/RIA ratio 1.05 +/- 0.04, range 0.84 to 1.28). It is concluded that receptoractivity of HGH is parallel to its immunoreactivity in normal children and in hypopituitary patients clinical grade HGH.

[Plasma dehydroepiandrosterone concentrations in normal boys and in those with growth retardation]

Radioimmunoassay of plasma DHA in 179 boys 2 to 16 years old has allowed assessment of normal values (mean and 95% confidence limits) increasing with age on a log DHA/age relationship. Plasma DHA was normal in 58 cases of male idiopathic growth retardation and 40 boys with delayed adolescence. It was significantly increased in 42 obese boys. DHA levels were normal in 10 hypopituitary dwarfs with isolated GH deficiency, and significantly decreased in 24 others with multiple pituitary deficiencies. In pituitary dwarfism, a lowered DHA level may be a reliable index of ACTH deficiency, and may be of importance for evaluation of therapeutic programmes.

[Thyroid dysgenesis in mother and daughter]

A case of congenital hypothyroidism with lingual thyroid in a woman and her daughter is presented. The scarcity of familial cases of thyroid malformations leads to discuss the genetic factors involved.

Pituitary LH and FSH and testosterone secretion in infants with undescended testes

Twelve male infants with undescended testes (5 bilaterally, 7 unilaterally) were studied between the ages of 1 week and 11 months. As in older pre-pubertal cryptorchid boys, a significant decrease of the LH response to LH-RH test was found, while basal plasma levels of gonadotrophins and FSH response to LH-RH were normal. Plasma testosterone levels were in the normal range, and Leydig cells responded to stimulation by HCG, the degree of this response being significantly and positively correlated to the LH peak elicited by LH-RH. It may be concluded that some early defect of the pituitary-Leydig cell axis is associated with undescended testis.

The use of luteinizing hormone-releasing hormone in pediatric patients

Luteinizing hormone-releasing hormone (LH-RH), first synthetized in 1971; became soon available for clinical purposes and was immediately used as a diagnostic tool in children and adolescents as well as in adults. The first results of the LH-RH test in pediatrics were reported in 1972 and soon after discussed in meetings allowing comparison of the data from different groups. From this time, a great number of publications has been devoted to the diagnostic usefulness of LH-RH in the study of pubertal development and of pituitary-gonadal disorders in children and adolescents. Until recently, the theraeputic use of LH-RH has been restricted by the lack of availability of sufficient amounts, so that only few preliminary data have been reported in this field. Thus the scope of this review is mainly to present a critical survey of the data concerning LH-RH test in pediatric patients.

Effect of 24 hour fast in obese children

Effects of a 24 hour fast were studied in 21 obese children aged 7 to 14 and in 8 controls. Mean blood glucose (BG) during fast dropped more in controls (0.88 to 0.54 g/l) than in obese (0.90 to 0.63 g/l) Plasma cortisol changes were similar in the 2 groups, FFA increased (p less than 0.01) in the 2 groups, but the 24 hour mean level was higher in controls (4.0 mEq/l) than in obese (2.06 mEq/l). At the end of the fast, a ketonuria was present in all obese children except 2. Serum alanine dropped similarly in obese (28 to 24 muM p. cent ml) and in controls (30 to 22 muM p. cent ml). All obese exhibited at the end of the fast a significant rise (p less than 0.01) of branched chain aminoacids, not observed in controls. Responses to glucagon (0.03 mg/kg I.M.) were studied before and after fast. At time 0, BG response was higher and more prolonged in obese in spite of hyperinsulinism. At time 24 hours, BG raised from 0.50 to 0.74 g/1 and insulin from 8 to 35 muU/ml in controls, while in obese BG raised from 0.63 to 1.06 g/l and insulin from 25 to 88 muU/ml. Concomitant hyperinsulinsim and biological criteria of hypoinsulinism demonstrated in obese children the peripheral resistance to insulin. The contrast between a normal degree of protein gluconeogenesis and a reduced rate of fat mobilization during fast may be a major biological feature of obesity in childhood.

[Infantile and juvenile hypothyroidism with the gland in place and low radio-iodide uptake]

27 hypothyroid infants of children, with a low iodine uptake in spite of a thyroid gland or thyroid tissue in normal pretracheal place, have been studied. 21 cases are related to primary thyroid involvement leading to vanishing iodine or technetium uptake. In 8 of these cases, clinical onset in late childhood, high frequency of antithyroid antibodies and of familial thyroid dysfunction were similar to those found in childhood's thyroiditis. 8 other cases had a precocious onset (first months in 6, first year in 1, second year in 1) with some pretracheal iodine uptake when first studied and no uptake at further examinations, 1 patient having received no treatment from first to second study, the others being without treatment from more than two months and certain of them receiving injections of TSH. The last 5 cases of this group were those of children born to 2 mothers with treated hypothyroidism, with low iodine uptake in pretracheal place. The role of genetic factors and auto-immunity in theses cases is discussed. The 6 other patients had clinically isolated hypothyroidism secondary to TSH deficiency, eventually associated to clinically inapparent GH or ACTH deficiencies, most of them by hypothalamic defect with normal response to TRH.

[Endocrine exploration in Prader-Labhardt-Willi syndrome]

In nine children with Prader-Labhardt-Willi syndrome, some tests of anterior pituitary functions and insulin secretion have been performed. The endocrine disturbances found in these cases have been those commonly encountered in obese and/or cryptorchid subjects, so that they do not allow to ascertain a primary hypothalamo-pituitary defect.

Effect of synthetic luteinizing hormone-releasing hormone on the release of gonadotropins in hypophysogonadal disorders of children and adolscents. VII. Constitutional delay of puberty in males

Serum gonadotropins (LH and FSH) were measured by radioimmunoassay before and after intravenous injection of 0.1 mg/m2 of synthetic luteinizing hormone-releasing hormone in 20 male patients, aged 15 to 18 years, with constitutional delay of puberty. Basal plasma levels of LH and FSH were in the prepubertal range. After administration of LH-RH, the increase in LH was significantly high than in prepubertal control subjects, aged 1 to 13 years; the difference between test patients and pubertal control subjects was not significant. The increase in FSH was in the prepubertal range, significantly lower than that in pubertal control subjects. This discrepancy between LH and FSH responses to LH-RH is similar to that observed in normal boys at the late prepubertal stage and suggests that an elevation of readily releasable pituitary stores of LH correlates with the first step of pubertal onset in males, even if puberty is delayed.

[Hypophyseal gonadotropin secretion in sexual precocity with McCune-Albright's syndrome]

In three young girls with isosexual precocity and fibrous dysplasia of bones, plasma gonadotropins (LH and FSH) response to releasing hormone (LH-RH) has been much under the mean response in true female precocious puberty. These data and those previously reported in the literature suggest that MacCune-Albright's syndrome correlates to an hypothalamo-pituitary dysfunction rather than to a true prematurity.

[Paraneoplastic precocious puberty in a child. Mediastinal teratoma with chorionic gonadotropin secretion]

A case of precocious puberty in a 5-years old boy with a rapid increase of androgens, small testes, a high level of urinary bioassayable gonadotrophins, but no response of pituitary gonadotrophins of LH-RH injection. The cause was a mediastinal teratoma secreting chorionic gonadotrophin (HCG and beta subunit).

[Corticosuprarenaloma in children]

Thirty-four cases of corticosurrenaloma with clinical onset before 15 years of age have been studied. Higher frequency in girls (65 percent of the cases) and in young age (80 percent before 5 years of age, 43 percent before 2 years), association with personal or familial other tumors and malformations, are noticeable features. Virilism is the major manifestation in children (83 percent of the cases), either isolated or associated with hypercortisolism and/or feminization. Hormonal assays are of little value, and the dynamic adrenal tests are of some help only in small tumors or isolated hypercortisolism. Radiological diagnosis by urography with cavography, arteriography, is easy in most cases. Evaluation of prognosis is very difficult. Clinical and biological data are not significant, histological data are often of little help. Only a very large mass, and occurrence of metastases (liver, lungs) evidence malignancy. This series does not allow to assess definitely the best therapeutic regimen. Surgery has to be performed as soon as possible. The effects of radiations have not yet been ascertained. High doses of op'DDD have led to a sustained remission of the tumor or metastases in 2 patients, and perhaps to a longer survival in 4 others.

[Sensitivity of isolated rabbit articular chrondrocytes to the somatomedin activity of human serum]

Rabbit articular chondrocytes, isolated and incubated in vitro, incorporate tritium-labelled thymidine. Thymidine incorporation is stimulated by normal human serum, this effect being related to serum concentration and increased by addition of poly-DL-ornithine. The stimulatory effect of the serum from hypopituitary dwarfs is low and is not increased by poly-DL-ornithine.

[Isolated premature breast development in young girls. Results of the LH-RH test]

Thirty-six cases of premature thelarche in girls 9 months to 7 years old have been studied. In most cases, breast development began before 3 years and came to regression. Onset after 3 years was less common and led usually to breast persistance. Height was lightly but significantly advanced. Plasma levels of estrone, estradiol (in 21 cases) and gonadotropins (FSH and LH, in 12 cases) were not significantly increased. However, LH-RH test (in 12 cases) suggested prolongation and/or increase of the physiologic gonadotropic hyperactivity of normal female infants.

Effect of synthetic luteinizing hormone-releasing hormone (LH-RH) on the release of gonadotrophins in children and adolescents. VI. Relations to age, sex and puberty

Plasma gonadotrophins (LH and FSH) were radio-immunoassayed before and after injection of 0.1 mg/m2 of synthetic luteinizing hormone-releasing hormone (LH-RH) in infants 1 to 12 months old, prepubertal children aged more than 12 months, and pubertal subjects of both sexes. The pubertal changes of gonadotrophins include a highly significant increase of LH pituitary mobilizable reserve in both sexes, while the FSH reserve shows a significant decrease in females and no significant variation in males. From the first year of life up to childhood, the basal blood levels of FSH and LH decrease significantly in girls but do not vary in boys, while the FSH reserve decreases significantly in girls and increases significantly in boys, the LH reserve showing a non-significant decrease in both sexes. In the first year of life, girls show a very significantly higher FSH secretion and reserve than boys, while boys have a significantly higher LH reserve than girls. After the end of the first year up to the onset of puberty, the FSH reserve remains significantly higher in girls than in boys. The interpretation of these facts is discussed.