Adrenal androgens in children with short stature

Recent data suggest that adolescent individuals with growth hormone (GH) deficiency have subnormal levels of adrenal androgens (AA). In order to determine the developmental pattern of AA in GH deficiency and to assess whether AA levels can help identify children with GH deficiency, we measured plasma concentrations of dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), delta 4-androstenedione (delta 4A), and cortisol in the basal state and during prolonged adrenocorticotropin (ACTH) infusion (8 h) in a group of 34 individuals, 26 males and 8 females, with short stature. Their chronological ages (CA) ranged from 1.75 to 17.5 years (median 10.35 years). The subjects were grouped into two categories according to the results of pituitary testing: group 1 = short, non-GH-deficient (n = 16), and group 2 = GH-deficient, ACTH-sufficient (n = 18). Patients in groups 1 and 2 had similar bone ages (BA: 7.2 +/- 0.7 vs. 7.5 +/- 1.0 years) and Z scores for height (-3.0 +/- 0.2 vs. -3.2 +/- 0.3 units) and height velocity (-2.5 +/- 0.4 vs. -2.6 +/- 0.2 units). For both groups there were significant increases from basal to peak levels for DHEA, DHEA-S, delta 4A and cortisol following prolonged ACTH infusion. Although both basal and peak levels of DHEA-S overlapped in groups 1 and 2 for all CA and BA, levels in group 2 tended to be lower, especially for BA greater than 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spontaneous growth hormone secretion and plasma somatomedin-C in children of short stature

We studied 17 short prepubertal children, aged 7.5 to 17.0 years (mean +/- SD: 11.7 +/- 2.4) more than 2.0 SD below the mean height for their age and of delayed bone age (M +/- SD: 8.1 +/- 2.3), to clarify their physiological GH secretory status. The mean concentration of GH (MCGH) was calculated and was compared with the subjects' GH responses to insulin and arginine tolerance tests (IATT) and plasma somatomedin-C (SM-C). The mean 24-h MCGH value was 3.2 +/- 1.3 ng/ml (range 1.6-5.5). The mean peak GH response to the IATT was 13.0 +/- 7.5 ng/ml (range 2.4-33.9). In addition to the two patients with abnormally low GH responses to the IATT, seven with normal responses showed low 24-h MCGH values, a small number of GH pulses and low mean GH amplitude. The mean plasma SM-C in all patients was 0.60 +/- 0.20 U/ml. This was significantly lower than that of age-matched children of normal height (p less than 0.001). The 24-h MCGH was significantly correlated with plasma SM-C levels (r = 0.51, p less than 0.05) and with that of the first three hours of sleep at night (r = 0.84, p less than 0.01). These results indicate that: 1) some short children with normal GH response to pharmacological tests secrete a low amount of GH physiologically and 2) blood sampling during the first three hours of sleep as well as 24-hour sampling is suitable in evaluating the physiological secretion of GH.     

Euthyroid hypothyrotropinemia in children of short stature

Unique association of hypothyrotropinemia with euthyroidism was described in 2 children of short stature. Both had a history of intrauterine growth retardation (IUGR), but showed an appropriate growth rate after infancy (5 cm/y). Growth hormone secretion after provocation tests was normal, whereas TSH response to TRH was absent. With a highly sensitive TSH radioimmunoassay (RIA) and a specific RIA for TSH-alpha-subunit, both responded to a high dose of TRH stimulation. Serum thyroid hormones were within the normal range, while prolactin response to TRH was exaggerated. Exogenous thyroxine (T4) supplement in case 1 did not improve his growth rate, indicating absence of hypothyroidism. Case 2 was treated with stanozolol, which accelerated his growth velocity to 8 cm/y. During the treatment, serum T4 gradually decreased to 50% of the initial level, but blunted TSH response to TRH remained unchanged. These results indicate that their thyrotrophs are resistant to TRH stimulation and the pituitary setpoint of TSH release is unusually high. The exact mechanism involved in maintaining euthyroidism despite hypothyrotropinemia remains to be elucidated, but a common history of IUGR appears to play a role in producing this pituitary-thyroid state.     

Reduced pituitary volume in children with short stature: clinical and radiological correlates

A retrospective evaluation of 80 cases of growth retardation evaluated at the H?pital Sainte-Justine of Montreal has revealed that 20 of them (25%; 15 boys and 5 girls) had a reduction of pituitary volume as revealed by high-resolution CT scanning of the pituitary gland. Of these patients, 8 had complete growth hormone (GH) deficiency, as evaluated by arginine infusion and L-Dopa-propranolol testing and nocturnal blood sampling, and 3 had GH neurosecretory dysfunction. Five patients had combined or multiple hormonal deficiencies. A statistically significant correlation was found between nocturnal plasma GH values and pituitary volumes. From this study it can be concluded that reduced pituitary volume is a frequent finding in growth-retarded children with hypopituitarism.     

Physiological growth hormone secretion in children with short stature and intra-uterine growth retardation

31 prepubertal children with short stature [mean height standard deviation score (SDS) -2.84] and low birth weight (mean -2.82 SDS) were studied. Mean age was 6.0 years and mean height velocity SDS was -0.76. Patients were classified as having either the clinical characteristics of Russell-Silver syndrome (RSS) (4 F, 13 M) or not (4 F, 10 M). All children had an overnight profile of spontaneous growth hormone (GH) secretion. 4 children achieved a maximum GH concentration of less than 20 mU/l. 9 children with RSS secreted only one large GH peak during the night. Most of the non-RSS group had normal GH pulse frequency but 3 boys had a fast-frequency pattern. Abnormal GH secretion may contribute towards growth failure in children with low birth weight/RSS.     

Circadian variation in human stature

The aim of this study was to monitor the creep in stature due to compression and its recovery over 24 hr in eight adult males. Measurements of stature were made at nine times during the 24-hr cycle using a purpose built metal frame tilted 5 degrees to the vertical. Accessories for standardization of posture and prevention of unwanted muscular tension included a series of microswitches on the frame, cross-beams for controlling spinal curvatures, slit spectacles used in conjunction with a mirror for proper head alignment. A dead load BAYE micrometer recorded stature to 0.01 mm. A significant circadian rhythm was established, the trough to peak variation being 19.3 mm or 1.1% of overall stature. Peak stature was measured at 0730 on awakening and the trough occurred at midnight before assuming a recumbent posture for sleep. Altogether 71% of the height gained during the night was achieved in the first half of the night's sleep. Over 50% of the height loss in a day was lost within the first hour of rising, 80% being lost within 3 hr of arising: the rate of creep decelerated throughout the remainder of the waking day. It is concluded that the rate of change in creep throughout the day varies, being greatest in the morning whilst distension is most pronounced in the early hours of sleep.     

Comparison of spontaneous growth hormone secretion during daytime and sleep in children with short stature

The authors compared diurnal growth hormone (GH) secretion with GH secretion during sleep in 24 children with delayed growth. In group I (children with normal response to provocative tests), the level of daytime secretion was lower than that of nocturnal secretion. In 3 of 9 cases, daytime secretion was abnormal, whereas nocturnal secretion was normal. In 2 cases, both diurnal and nocturnal secretion were abnormal, but response to provocative stimuli was normal. In group II (children with a false partial GH deficiency, i.e. with inadequate response to provocative tests, GH peak less than 11 ng/ml and normal nocturnal secretion), the results were comparable with those of group I, with extremely low diurnal secretion in 6 of 9 cases. In group III (children presenting true partial GH deficiency, i.e. GH less than 11 ng/ml in response to provocative tests together with abnormal nocturnal secretion), both diurnal and nocturnal GH secretion were insufficient, with nonexistent diurnal secretion in 5 of 6 cases. Diurnal secretion does not seem to be a reliable indicator of 24-hour spontaneous secretion.     

A proteomic approach identified growth hormone-dependent nutrition markers in children with idiopathic short stature

Background  

The broad range in growth observed in short prepubertal children receiving the same growth hormone (GH) dose is due to individual variation in GH responsiveness. This study used a pharmaco-proteomic approach in order to identify novel biomarkers that discriminate between short non-GH-deficient (GHD) children who show a good or poor growth response to GH treatment.     

Novel treatment of short stature with aromatase inhibitors

Estrogens have an essential role in the regulation of bone maturation and importantly in the closure of growth plates in both sexes. This prospective, randomized, placebo-controlled study was undertaken to evaluate whether suppression of estrogen synthesis in pubertal boys delays bone maturation and ultimately results in increased adult height.

A total of 23 boys with constitutional delay of puberty (CDP) received a conventional, low-dose testosterone treatment for inducing progression of puberty. Eleven of these 23 boys were randomized to receive a specific and potent P450-aromatase inhibitor, letrozole, for suppression of estrogen action, and 12 boys were randomized to receive placebo. Estradiol concentrations in the letrozole-treated boys remained at the pretreatment level during the administration of letrozole, whereas the concentrations increased during the treatment with testosterone alone and during spontaneous progression of puberty. Testosterone concentrations increased in all groups, but during the letrozole treatment, the increase was more than fivefold higher than in the group treated with testosterone alone.

The inhibition of estrogen synthesis delayed bone maturation. The slower bone maturation in the boys treated with testosterone and letrozole, despite higher androgen concentrations, than in the boys treated with testosterone indicate that estrogens are more important than androgens in regulation of bone maturation in pubertal boys. During the 18 months follow-up, an increase of 5.1 cm in predicted adult height was observed in the boys who received testosterone and letrozole, but no change was seen in the boys who received testosterone alone or in the untreated boys. This finding indicates that an increase in adult height can be attained in growing adolescent boys by inhibiting of estrogen action.     

Genetic analysis of short stature

Short stature is a major concern for patients and their parents, and represents a diagnostic challenge to the clinician. A correct diagnosis is of particular importance in view of the availability of effective, but costly, therapy in a small subset of cases. Many different genetic etiologies of short stature are known. Therefore, chromosome as well as molecular analysis are requisite diagnostic investigations in children with short stature. Particularly in the group of children with idiopathic short stature, possibilities of molecular analysis are often underestimated. Important options are UPD7 and the FGFR3, SHOX, GH1 and GHR genes. Furthermore, analysis of the IGF and IGF1R genes should be considered. We propose a flow chart for molecular analysis in short stature.     

Effect of chronic clonidine treatment on urinary growth hormone excretion and linear growth in children with short stature

Eleven prepubertal children with short stature were treated with clonidine (0.15 mg/m2 daily) for a period of 1 year. The effect of this drug was evaluated on both clinical (growth velocity, height standard deviation scores for chronological age and bone age) and hormonal (urinary growth hormone excretion and insulin-like growth factor I) parameters. Our study shows that long-term clonidine administration in children with short stature did not result in significant differences in growth velocity, height standard deviation scores for chronological age and bone age, insulin-like growth factor I or in urinary growth hormone excretion.     

Growth response of Egyptian children with idiopathic short stature during four years of growth hormone therapy

BACKGROUND:

Multiple factors affect the growth response to recombinant human growth hormone (rhGH) in children with idiopathic short stature (ISS).

AIM:

To evaluate the growth responses of children with ISS treated with rhGH, aiming to identify the predictors of growth response.

MATERIALS AND METHODS:

We studied 120 cases, 90 males (75%), with a mean age of 13.8±2.7 years and 30 females (25%), with a mean age of 12.3±2.5 years. All patients received rhGH with a standard dose of 20 IU/m²/week. The calculated dose per week was divided into six days and given subcutaneous at night.

RESULTS:

A significant positive trend was detected in the delta changes of all anthropometric data. For the first year, the growth response was positively correlated to CA and BA delay and negatively correlated to height, weight and IGF-1 SDSs. For the second year, the growth response was correlated positively to first year growth velocity, BA, triceps skin fold thickness SDS and deviation from target height, and negatively correlated to weight, IGFBP3 SDS and target height SDS. For the third year, the growth response was positively correlated to five variables namely target height, 2^nd year growth velocity, IGF-1 SDS, weight SDS and triceps skin fold thickness SDS. For the fourth year, growth response was positively correlated to 2^nd and 3^rd year growth velocity, BA, deviation from target height and weight/ height SDS.

CONCLUSION:

Our study showed multiplicity of predictors that is responsible for response in ISS children treated with rhGH, and BA was an important predictor.