Effects of hypopituitarism and growth hormone replacement therapy on the production and utilization of glucose in childhood

Glucose metabolism during fasting was investigated in 10 children aged 1.5 month-11.5 yr with deficiency of GH with or without other pituitary hormone deficiencies. After 10-16 h of fasting, mean plasma glucose was 56 +/- 4 (SEM) mg/dl, the result of decreased hepatic production of glucose (3.3 +/- 0.3 mg kg-1 min-1) insufficient to match glucose utilization (3.6 +/- 0.4 mg kg-1 min-1). The diminution of plasma glucose and of glucose production was similar whether ACTH deficiency was present (3.2 +/- mg kg-1 min-1) or not (3.5 +/- 0.6 mg kg-1 min-1). These results indicate that the lack of GH was the primary cause of hypoglycemia. Fasting plasma alanine (212 +/- 41 mumol/liter) and lactate (1222 +/- 136 mumol/liter), the main gluconeogenic substrates, were normal and did not correlate with the decrease of hepatic glucose release. Both plasma FFA (552 +/- 35 microM) and beta-hydroxybutyrate (654 +/- 158 microM) were in the low normal range, and neither correlated with the rate of glucose utilization. hGH replacement therapy resulted in a normalization of fasting plasma glucose concentration (78.5 +/- 6 mg/dl, P less than 0.005) and hepatic glucose production (6.1 +/- 1.2 mg kg-1 min-1). No significant changes occurred in the plasma concentrations of gluconeogenic or lipid substrates. These results, together with the known stimulatory effects of GH on carbohydrate-induced insulin secretion and storage of hepatic glycogen, suggest that the changes in glucose production in untreated and GH treated patients reflect the degree of hepatic glycogen replenishment.

Plasma gonadotropin and testosterone values in infants with cryptorchidism

Plasma gonadotropins and testosterone levels have been studied from day 30 +/- 6 to day 120 +/- 10 in 57 term male infants born with undescended testes-bilaterally in 22 and unilaterally in 35. Clinical follow-up of these infants showed that spontaneous testicular migration occurred at 2 to 4 months in 27 of them; the 30 others remained cryptorchid at 6 months. Plasma LH and the postnatal rise in testosterone concentration were significantly lower in patients remaining cryptorchid, either unilaterally or bilaterally, than in infants with delayed spontaneous descent of one or both testes. A significant positive correlation was found betwen plasma LH and testosterone values within these two groups of subjects. Plasma FSH levels were not different in the two groups. These data suggest a primary LH deficiency in cryptorchidism, resulting in a blunted postnatal secretion of testosterone. It may be speculated that the early postnatal deficiency of the LH-Leydig cell axis in cryptorchid patients contributes to impair both testicular migration and maturation.

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.

Glycemic response to 24-hour fast in normal children: III. Influence of age

A 24-hour fast was performed in 28 normal children-17 boys and 11 girls, 2 to 17 years of age. After the fast, blood was drawn for blood sugar, plasma growth hormone and cortisol, serum free fatty acids and alanine measurements. Blood sugar values ranged between 30 and 77 mg/dl and were significantly correlated to age (R = 0.68, P less than 0.001). Plasma cortisol (R = 0.73, P less than 0.001), GH (R = 0.57, P = 0.01), and FFA (R = 0.76, P less than 0.001) were negatively correlated to age. Serum alanine fasting values ranged between 10 and 36 micrometer/dl and were significantly correlated to age (R = 0.86, P less than 0.001) and to blood sugar values (R = 0.54, P less than 0.01). These data demonstrate that carbohydrate regulation during fast improves with age in children, correlating with higher levels of gluconeogenic substrates and a lower rate of lipolysis.

A possible common origin of "Y-negative" human XX males and XX true hermaphrodites

We have studied nine patients aged 1 month to 16 years with 46, XX karyotypes and testicular tissue. Some of these patients were followed through puberty. Phenotypically, two presented normal and seven abnormal external genitalia (AG). Among this latter group, four showed hypospadias and three true hermaphroditism (TH). The endocrine data were similar in all three groups: testosterone levels were within normal limits during puberty, decreasing in adulthood; gonadotrophin levels were above the control values at mid puberty. Histologies of the two sub groups of AG patients were identical up to 5 years of age and presented differences when compared with controls, regardless of the ovarian part of the ovotestis. However, in patients older than 8 years, germ cells disappeared and dysgenesis became obvious. In one patient, the ovarian zone of the gonad was detected only after complete serial sections of the removed gonad were examined. Southern blot analysis with Y-DNA probes displayed Y-specific material for the classic 46 XX males and a lack of such sequences for all patients with AG and TH. Based on these findings, we postulate that 46, XX males with AG and 46, XX TH may represent alternative manifestations of the same genetic defect. These data together with those concerning familial cases of 46, XX males with AG and 46, XX TH suggest an autosomally (or pseudoautosomally) determined mechanism.

Reduced post-natal rise of testosterone in plasma of cryptorchid infants

Plasma testosterone has been studied in 31 full-term male infants born with bilaterally undescended testes (14) or unilaterally undescended testis (17). From 10 to 89 days after birth, the post-natal testosterone rise was significantly lower in the 18 infants who remained cryptorchid at 4 months than in the 13 who underwent spontaneous testicular descensus and in the normal controls. Blunted post-natal Leydig cell secretion in cryptorchids may relate to a primary LH defect and could contribute to the impairment of both testicular descensus and maturation.

Long-term results of growth hormone treatment in France in children of short stature: population, register based study

OBJECTIVES

To describe the growth of children treated with growth hormone and to evaluate the prognostic factors for height at the end of treatment.

DESIGN

Register based cohort study.

SETTING

French national register of all children treated with growth hormone.

SUBJECTS

3233 short stature children (3165 of whom were deficient in growth hormone) who were treated with growth hormone (excluding children with Turner's syndrome) and whose treatment started between 1973 and 1989, last data being recorded in December 1993.

MAIN OUTCOME MEASURES

Annual changes in height, and height at the end of treatment.

RESULTS

Mean height SD score at the end of treatment, after a mean of 4.3 years, was -2, corresponding to gain in mean height SD score of 1 and to a height SD score of 1.1 below target height. In all, 923 children prematurely stopped taking growth hormone treatment, mainly because of insufficient response (insufficient growth) or tiredness. Variables that predicted height at the end of treatment were age, target height, aetiology of short stature, use of puberty inhibitors, and type of growth hormone.

CONCLUSIONS

The outcome of children of short stature with growth hormone deficiency who were treated with growth hormone has been less favourable than initially assumed. Growth hormone treatment has not restored normal growth to these children. The highly demanding nature and high costs of this treatment require an optimised prescription, and this remains to be determined.

The pituitary-gonadal axis in cryptorchid infants and children

We have attempted to document in cryptorchid children that there is an LH deficiency and a secondary deficiency of testosterone. We have shown a diminished LH peak after LH-RH in cryptorchid versus normal infants (P less than 0.05). The postnatal surge of testosterone is significantly low (P less than 0.001) in permanent cryptorchids versus infants with secondary testicular descent, whose levels are similar to those in controls. In permanent cryptorchids during the same period (0-4 months), LH and testosterone levels were significantly lower (P less than 0.01 and P less than 0.05 respectively) than in infants with secondary descent, and the levels of testosterone and LH were correlated in both populations. In children, a low basal level of LH was observed at pubertal stage P2, and LH peak after LH-RH was significantly reduced at stages P1 and P2 (P less than 0.01 and P less than 0.05 respectively). The post-stimulatory levels of testosterone after hCG were reduced at the same stages (P less than 0.01, P less than 0,05), and the two levels were correlated (P less than 0.01). No differences are seen for LH and testosterone afterwards. It has been possible to show by immunofluorescence on pituitary cells the occurrence of antigonadotropin cell antibodies (AGCA) in more than 50% of our patients, with no relation to age and no correlations between endocrinological data and the presence or absence of AGCA. The relatively low success rate of hCG treatment, mainly in young children, and of GnRH irrespective of the regimen of treatment, does not exclude the role of primary LH deficiency in cryptorchidism.

Growth hormone response to thyrotropin-releasing hormone and oral glucose-loading tests in tall children and adolescents

The effects of TRH and oral glucose loading on the release of GH were investigated in 10 children or adolescents with constitutional tall stature. Eight of these children had a family history of above average height. The mean (and SEM) baseline GH levels (3.12 +/- 2.0 ng/ml) were similar to those in control subjects. Somatomedin activity, measured by sulfate incorporation into chick embryo cartilage, was elevated. Oral glucose loading caused an early significant increase in plasma GH at 30 min in 2 of these subjects and a late rise at 180 min in 4 others. Intravenous injection of synthetic TRH (0.2 mg/m2) caused a marked increase in plasma GH (17 +/- 3.0 ng/ml) in 7 of the 10 patients; the peak of GH was observed within the first hour after the injection of TRH in 3 cases, while a later peak was observed in the second hour after injection in 4 others. Peak plasma PRL (47 +/- 3.8 ng/ml) and TSH (20 +/- 1.2 microU/ml) levels in response to TRH were normal. These results suggest a disorder of hypothalamo-pituitary regulation of GH secretion in certain children with apparently constitutional tall stature. Similar findings in a probably preacromegalic girl are reported.

Falsely elevated serum thyrotropin (TSH) in newborn infants: transfer from mothers to infants of a factor interfering in the TSH radioimmunoassay

In a TSH screening program for congenital hypothyroidism we detected seven newborn infants with normal plasma T4 and T3 levels but high immunoassayable TSH. Similar findings were obtained in their mothers. Serial plasma dilution curves, with and without the addition of normal rabbit serum to the samples, showed that the result of TSH assay performed with antihuman TSH rabbit antiserum was falsely elevated in mothers and infants by an interfering factor. Follow-up of the infants demonstrated that the falsely elevated plasma TSH levels returned to normal within the first 6 months of life. On the contrary, plasma TSH levels remained high in the mothers. These results suggested a placental transfer of maternal antibodies. Indeed, the analysis of the mothers anamnesis revealed that all had previously received injections of a microbial vaccine cultured on a rabbit lung-containing medium. We conclude that placental transfer of a maternal antirabbit factor may cause an artefactual hyperthyrotropinemia in the newborn and the incorrect diagnosis of neonatal hypothyroidism. This can be avoided by the addition of normal rabbit serum or immunoglobulin to the TSH RIA tubes.

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.

Correlation of pituitary and testicular responses to stimulation tests in cryptorchid children

LH-RH test and HCG stimulation test were performed in 154 cryptorchid boys aged 1 month to 15 years (64 unilateral and 90 bilateral). Basal plasma LH levels and LH response to LH-RH were significantly lower from infancy to early puberty in cryptorchids compared with controls. Basal FSH levels and FSH response to LH-RH were normal. The post-HCG rise of plasma testosterone was reduced until mid-puberty. A significant positive correlation was found between post-HCG testosterone levels and pre- and post-LH-RH levels of LH. This correlation suggests that testicular maldescent and the decreased ability of Leydig cells to respond to a short course of HCG may result from an early defect or a delay of pituitary LH secretion.

Serum insulin-like growth factor 1 and serum growth-promoting activity during the first postnatal year in infants with intrauterine growth retardation

Follow-up from birth to age 12 months was obtained in 21 infants born with intrauterine growth retardation. Serum insulin-like growth factor 1 was measured by radioimmunoassay. The bioassayable growth-promoting activity of the serum was measured as the "thymidine activity" on lectin-activated lymphocytes at 5 days and 1, 3, 6, 9, and 12 months, and was compared with control values. Depending on their length at age 12 months, the intrauterine growth retardation infants were divided into three groups: at or above the average (n = 8, group A), between the mean and -2 SD (n = 7, group B), or less than -2 SD (n = 6, group C). No differences in nutritional indexes or in head circumference were found between the three groups. Insulin-like growth factor 1 was significantly lower at age 5 days in intrauterine growth retardation than in control infants. It increased slowly in groups A and B to reach the control values at age 9 and 12 months. In group C it remained significantly subnormal at 1 yr of age. Thymidine activity was also significantly lower at age 5 days in intrauterine growth retardation compared with control infants. It increased sharply at age 1-3 months in groups A and B but remained significantly lower in group C up to 1 yr of age. Although individual values of insulin-like growth factor 1 and thymidine activity were closely correlated, the increase of length during the first postnatal year correlated significantly with the thymidine activity levels at 1 and 3 months but not with the insulin-like growth factor 1 levels at 1, 3, and 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous study of somatotrophic and corticotrophic pituitary secretions during ornithine infusion test

An ornithine infusion test was performed in fifty-four children with constitutional short stature. The ornithine infusion induced an elevated level of GH at 45 min (mean value = 873 pmol/l) and a similar rise of cortisol levels (mean value = 544 nmol/l). An important peak of ACTH appeared 15 min before the increase of cortisol. In three panhypopituitary dwarfs studied, no elevation of GH or cortisol was observed. The well tolerated ornithine infusion test allows the simultaneous study of the somatotropic and corticotropic pituitary secretions in children with delayed growth.

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.

Comparative study of biosynthetic human growth hormone immunogenicity in growth hormone deficient children

The immunogenicities of six recombinant human growth hormone (rhGH) preparations, from KABI (A rhGH191 and B rhGH192), Eli Lilly (C), Nordisk (D), Sanofi (E) and Serono (F), used to treat 260 GH-deficient children, have been compared using a common specific and sensitive procedure for antibody determination. For this purpose we developed two immunoassays: a competitive liquid radioimmunoassay using 125I-rhGH, and an immunometric solid enzymoimmunoassay in which the rhGHs were immobilized. Blood samples were collected from the GH-deficient children before treatment and after 3, 6, 9, 12, 18 and 24 months of therapy. Human GH antibodies were detected in children treated with 3 of the 6 rhGH preparations. Seven percent of the patients treated with hormone A, 14% with hormone B and 22% with hormone C formed antibodies against the respective rhGH. Differences in capacity and affinity of the hGH antibodies were observed between these anti-GH-positive groups. They could be divided into 2 groups according to their immunopotency. One group (7, 14 and 6% of the patients treated with hormones A, B and C, respectively) developed anti-hGH antibodies with very low binding capacities (30-100 fmol/ml). The other group (16% of the patients treated with hormone C) developed IgG-type antibodies to hGH with higher binding capacities (200-1,200 fmol/ml) and a measurable binding affinity (Ka = 10(8) M-1). These hGH antibodies partially inhibited the binding of labeled GH to its specific liver membrane receptor. However, because of their low titer, they did not inhibit growth in the treated children.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth hormone testing for the diagnosis of growth hormone deficiency in childhood: a population register-based study

Evaluation of GH secretion using pharmacological GH stimulation tests (GHST) remains a current practice, although the reliability of GHST has been questioned, and many pitfalls have been pointed out. We have analyzed all of the 6373 GH stimulation tests that led to the initiation of GH therapy in 3233 children treated in France from 1973-1989. Tests and GH measurements were performed by individual centers and collected by the Association France-Hypophyse. GH deficiency (GHD) was due to craniospinal irradiation (11%), was due to organic causes or associated with multiple deficiencies (22%), or was considered idiopathic (65%); 2% of the patients were considered non-GHD. Eleven different pharmacological tests were used, and 62 of the 66 theoretical pairs of tests were used at least once. The most frequent combination of tests (ornithine in one instance and insulin in another) was used in 12.7% of patients. The reliability of the GH peak measured by comparing the results of 2 tests in the same patient was poor, as measured by intraclass correlation coefficients below 0.8. Multivariate analysis identified several parameters positively or negatively associated with peak plasma GH: calendar year of initiation of treatment, etiology of GHD, height SD score, bone age SD score, puberty, weight SD score, genetic target height SD score, and the nature of the pharmacological agent used. We believe that several of these factors (weight SD score, genetic target height SD score, and nature of the agent) identify biases in the diagnosis of GHD. We conclude that GHST should be performed with a very limited number of agents, interpreted after the establishment of reference values in age-matched normal children, and associated with other clinical and biochemical parameters for establishing the diagnosis of GHD.

Thyrocalcitonin: effect on idiopathic hypercalcemia

Identical twins having idiopathic hypercalcemia were treated with repeated doses of thyrocalcitonin extracted from porcine thyroid glands. The treatment produced a marked change in the amount of calcitum and phosphate in the plasma and in the excretion of urinary calcium.

Variations of plasma growth hormone (GH)-releasing factor levels during GH stimulation tests in children

GH-releasing factor (GHRH) was measured by RIA in the plasma of 22 constitutionally short children given an ornithine infusion or an oral dose of L-dopa. After an overnight fast and 1 h of rest, plasma GHRH levels were 49.7 +/- 7.3 pg/ml (+/- SEM). In 5 children, L-dopa induced an increase in mean GH levels from 1.8 to 12 ng/ml at 60 min. Mean plasma GHRH levels increased from 47 pg/ml to a peak of 96 pg/ml at 15 min (P less than 0.02). In 4 other children, no increase in either GH or GHRH occurred after L-dopa treatment. In these 9 children, a significant correlation was found between the peak GH and GHRH concentrations (r = 0.841; P less than 0.001). On the contrary, ornithine-induced GH release was not preceded by a GHRH rise, but was followed by a GHRH decrease, from 51 to 27 pg/ml (P less than 0.02). We conclude that the 2 tests stimulate GH release in different ways, and that GH levels may be involved in the feedback control of GHRH secretion.

Endocrine and immunological findings in cryptorchid infants

In cryptorchid infants, significantly decreased mean levels of plasma testosterone and luteinizing hormone (LH) were found between the ages of 30 and 120 days. The levels of testosterone and LH were significantly correlated. No significant difference was found between infants with bilateral or unilateral cryptorchidism. After 120 days there was no longer any significant difference between cryptorchid infants and controls. No significant change in plasma follicle-stimulating hormone (FSH) was found. These data suggest that subnormal secretion of LH could be the primary abnormality in a proportion of boys with so-called common cryptorchidism. Our studies using LH-releasing hormone and human chorionic gonadotropin stimulation tests in older infants and children agree with the data obtained by measurement of basal plasma hormone levels during the first months of life. Anti-gonadotroph antibodies were found in the sera of approximately 50% of the cryptorchid children and infants studied, using an immunofluorescence technique. A study of 17 mothers and their infants gave concordant results in 16 pairs, 9 with and 7 without antibodies. This lead us to speculate on the possible role of maternal autoantibodies as a cause of partial gonadotrophin deficiency in the perinatal period and thus of testicular maldescent. As cryptorchidism is a syndrome, these findings do not mean that a similar mechanism is operative in all cases. However, these data do suggest that alternatives to the classical anatomical view of the descent and nondescent of the testes should be considered.