Urinary growth hormone excretion in post-menarcheal adolescent girls with type 1 diabetes

The aim of the present study was to compare measurements of urinary growth hormone (GH), serum insulinlike growth factor I (IGF-I) and IGF binding protein 3 (IGFBP3) between two groups of post-menarcheal girls, 13–18 y of age, one comprising 64 type 1 diabetic patients and the other 64 healthy girls matched for age and stage of puberty. GH was determined on two occasions in nocturnal urine samples by using a modification of an immunoradiometric method for serum. Significantly higher urinary GH concentrations but lower IGF-I and IGFBP3 levels were found in diabetic girls than in controls ( p < 0:001). A significant correlation was found between urinary GH concentrations and the daily dose of insulin (U kg ⁻¹) ( r = 0:426, p = 0:003). Urinary GH concentrations were also significantly related to HbA1c ( r = 0:380, p = 0:003). In conclusion, disturbances of the GH-IGF-I axis may be evaluated by the use of non-invasive urinary GH measurements, which is a simple alternative to frequent sampling of serum GH. Increased GH secretion seems to be related to a great need for insulin and poor metabolic control. More knowledge about underlying causal factors in the disturbed GH-IGF-I axis is required.     

Absence of hypoglycemia in response to varying doses of recombinant human insulin-like growth factor-I (rhIGF-I) in children and adolescents with low serum concentrations of IGF-I

AIM: To determine whether recombinant human insulin-like growth factor-I (rhIGF-I) administration to children with low IGF-I and relatively low insulin-like growth factor binding protein-3 (IGFBP3) serum concentrations would result in hypoglycemia. METHODS: Eighteen children age 11-19 y with serum levels of IGF-I< -2 SDS and IGFBP3< 0 SDS were randomly assigned to receive rhIGF-I at 80 microg/kg body weight daily (n = 6), 40 microg/kg twice daily (n = 6), or 80 microg/kg twice daily (n = 6). After a 10-d dose escalation and 15 d of treatment at the specified dosage, a 25-h pharmacokinetic/pharmacodynamic profile was obtained, which included 22 blood glucose measurements. Regular meals and snacks were provided. RESULTS: No signs or symptoms of hypoglycemia were noted throughout the study. There were no differences in mean blood glucose concentrations among the three dosage groups. The lowest glucose value recorded, 3.44 mmol/l, was 15 min after a morning injection of 80 microg/kg IGF-I, and promptly rose. Although subjects were selected on the basis of low concentrations of IGF-I to represent proposed candidates for rhIGF-I therapy, the mean and range of SDS for height were not different from those of previously studied normal Ecuadorian controls. CONCLUSION: In normal individuals with low serum concentrations of IGF-I and relatively low concentrations of IGFBP3, the administration of therapeutic doses of rhIGF-I, while maintaining reasonable food intake, does not result in hypoglycemia.     

Pubertal changes in serum leptin levels in adolescents with type 1 diabetes mellitus: a controlled longitudinal study

The mechanism of the pubertal delay seen in some adolescents with type 1 diabetes mellitus is not entirely clear. Since leptin has been implicated as a neuroendocrine modulator of puberty, we measured serum leptin levels longitudinally in 24 post-'honeymoon' patients with diabetes mellitus (M/F = 15/9) with a mean (+/- SD) age of 10.5 +/- 0.9 years and 26 controls (M/F = 15/11) with a mean age of 10.0 +/- 1.1 years. Physical examinations; serum leptin, IGF-I, IGFBP-3 and IGFBP-1 levels; and bone age X-rays were performed annually for up to 48 months. Glycosylated hemoglobin (HbA1c) was measured 2-4 times a year in patients with diabetes mellitus. Serum leptin levels strongly correlated with the body mass index z-scores (BMI-Z) in both controls (r = 0.666, p <0.00001) and diabetic patients (r = 0.577, p <0.00001). Girls had increased serum leptin levels for a given BMI compared to boys (p <0.005). There were no significant differences in serum leptin levels of patients with diabetes mellitus compared to controls, nor were differences seen when the groups were stratified by age, Tanner stage, or gender. There were also no significant correlations between serum leptin levels and degree of metabolic control (i.e. HbA1c) or insulin dose standardized for body weight. Although there was no significant diabetes-related or metabolic control-related delay in bone age z-score or pubertal development, there was a significant negative correlation between HbA1c and growth velocity z-score, indicating that children with poor diabetes control had modest but significant slowing of growth. It is concluded that neither pubertal development nor serum leptin levels are significantly altered in adolescents with diabetes mellitus managed with standard therapy. The potential role of leptin in initiation of pubertal development is not easily demonstrable in observational studies.     

Improvement of HbA1c without increased hypoglycemia in adolescents and young adults with type 1 diabetes mellitus treated with recombinant human insulin-like growth factor-I and insulin. rhIGF-I in IDDM Study Group

OBJECTIVE: A 12-week trial with insulin and rhIGF-I compared to insulin and placebo was conducted in patients with type 1 diabetes mellitus aged 11-66 years. We present the efficacy and safety data pertinent to the younger subset of participants (11-21 years). STUDY DESIGN: The patients were randomized to receive s.c. insulin and either placebo or rhIGF-I at one of the following doses (microg/kg): 40 a.m./40 p.m., 80 a.m./40 p.m. or 80 a.m./60 p.m.). RESULTS: The average decrease of HbA1c from baseline was higher (-1.3 +/- 0.2%) in the rhIGF-I treated group compared to the placebo group (-0.6 +/- 0.3%; p <0.05). This was associated with a significant decrease in daily insulin dose (U) of both Regular (rhIGF-I: -7 +/- 1; placebo: -1 +/- 1; p <0.01) and NPH (rhIGF-I: -4 +/- 2; placebo: +5 +/- 3; p <0.05). The incidence of hypoglycemia and weight gain were not increased. Edema, jaw pain and tachycardia were associated with rhIGF-I treatment, particularly at doses higher than 40 microg/kg b.i.d. Dose-related early worsening of retinopathy was observed in 11/55 patients in the rhIGF-I group, with resolution in the majority of them in the follow-up photographs. CONCLUSIONS: These findings suggest a possible role for rhIGF-I co-therapy in adolescents and young adults with type 1 diabetes mellitus.     

Factors involved in the regulation of plasma leptin levels in children and adolescents with anorexia nervosa

OBJECTIVE: The effects of changes in body mass index (BMI) and other factors on plasma leptin levels in children and adolescents with anorexia nervosa (AN) were examined. METHODS: Plasma leptin levels and BMI was measured before and after initiation of refeeding therapy every 2 weeks for 8 weeks in 12 children and adolescents with AN. The plasma levels of insulin, cortisol, insulin-like growth factor-I (IGF-I), and tumor necrosis factor-alpha (TNF-alpha) were also measured in these subjects before and after 8 weeks of the refeeding therapy, and the results were compared with those from 12 age-matched healthy girls. RESULTS: The plasma leptin and IGF-I levels, as well as the BMI, in the AN patients before refeeding therapy were significantly lower than both of these indices in the AN patients 8 weeks after initiation of the therapy and in the controls. The plasma leptin levels and BMI in the AN patients 8 weeks after initiation of the therapy were still significantly lower than those in the controls. Significant correlations between the plasma leptin levels and BMI were detected in the AN patients both before and 8 weeks after initiation of the refeeding therapy, as well as in the controls. The BMI showed a significant increase beginning at 2 weeks after initiation of the therapy compared with that before refeeding, but the plasma leptin levels did not significantly increase until 4 weeks after the initiation of therapy. CONCLUSION: The results suggest that plasma leptin levels reflect changes in body fat content in children and adolescents with AN, although there is a delay in the recovery of plasma leptin levels compared with those of BMI in the early period of refeeding therapy, which is probably regulated by other factors.     

Ghrelin, IGF-I and IGFBP-3 levels in children with type 1 diabetes mellitus

There is a strong relationship between ghrelin, insulin, glucose and IGF-I/IGFBP-3 metabolism. This aim of this study was to investigate ghrelin level, and its relationship with IGF-I and IGFBP-3 levels in children with type 1 diabetes mellitus (DM1). Twenty-seven children with DM1 and 25 healthy controls were investigated. Ghrelin levels were similar, and IGF-I and IGFBP-3 levels were lower, in prepubertal and pubertal patients compared to controls. In the patient group, ghrelin levels were negatively correlated with chronological age, height, weight, pubertal status and IGF-I, but had no correlation with fasting glucose, HbA1c, insulin dose, duration of insulin therapy, and IGFBP-3 levels. Similar ghrelin levels in patients compared to controls may suggest that ghrelin levels remain unchanged in children with DM1, or that altered ghrelin levels at diagnosis recover as a consequence of insulin therapy. The lack of correlation of serum ghrelin levels with fasting plasma glucose, HbA1c and insulin dose suggests that ghrelin level is not affected by these parameters. Decreased IGF-I level and its negative correlation with ghrelin are compatible with previous findings.     

Short-term insulin therapy in adolescents with type 2 diabetes mellitus

The optimum pharmacological treatment of type 2 diabetes mellitus (DM2) in youth for those who fail to achieve adequate glycemic control (HbA1c <7%) with lifestyle intervention is unknown. The aim of this pilot study was to observe the effect of short-term insulin therapy (<16 weeks duration) on glycemic control in youth with DM2. A pre-mix 30/70 insulin was given twice daily to 18 youth aged 10-18 years with DM2 for 8.7+/-4.3 weeks with a starting dose of 0.5 U/kg/day. HbA1c, body mass index (BMI) and episodes of hypoglycemia were monitored during the treatment period and for a 12-month period after insulin was stopped. Mean HbA1c decreased from 12.81% to 7.59% (95% CI 6.54, 8.64). This improvement persisted for 12 months without any further drug therapy. There was no significant change in mean BMI and there were no episodes of moderate or severe hypoglycemia. Decreasing beta-cell glucose toxicity with rapid improvement of blood glucose may play an important role in treatment of DM2 in adolescents. Early success in achieving target blood glucose levels is an important aspect of adolescent DM2 care.     

Leptin and metabolic hormones in infants of diabetic mothers

AIMS: To investigate the effect of maternal diabetes on leptin in term newborns and to determine whether leptin correlates with insulin and its associated biochemical parameters in support of the hypothesis that a functional "adipoinsular axis" might exist at this stage of development. METHODS: A total of 116 term newborns were prospectively enrolled and categorised into three groups: 44 were infants of non-diabetic mothers (control group C); 41 were infants born to mothers with gestational diabetes on dietary treatment (group D); and 31 were infants born to mothers with gestational or pregestational diabetes on insulin treatment (group I). RESULTS: No significant difference in serum leptin was observed between the three groups; the results of the study population were therefore pooled and analysed. Serum leptin correlated significantly with serum insulin, insulin:glucose ratio, birth weight, body length, body mass index, placenta weight, and maternal HbA(1c). Female infants had significantly higher serum leptin than male infants. All parameters except placenta weight and body length remained significantly associated with serum leptin when multivariate stepwise regression analysis was applied. Subgroup analysis revealed a significant correlation between serum leptin and cortisol in group D. CONCLUSIONS: There was no significant difference in serum leptin between infants born to diabetic and non-diabetic mothers, though infants born to mothers requiring insulin treatment had the highest median serum leptin concentrations. The significant association between serum leptin and insulin or insulin:glucose ratio supports the hypothesis that a functional adipoinsular axis might exist in term newborns. Furthermore, the significant correlation between maternal HbA(1c) and circulating leptin of the studied infants suggests that the clinical control of maternal diabetes could affect the regulation of serum leptin in these infants.     

Pharmacokinetics of recombinant human insulin-like growth factor I given subcutaneously to healthy volunteers and to patients with growth hormone receptor deficiency

The pharmacokinetics of recombinant human insulin-like growth factor I (rhIGF-I) were studied in healthy volunteers and in patients with growth hormone receptor deficiency (GHRD; Laron syndrome). Following single subcutaneous injections of rhIGF-I, 40 and 80 μgkg, to healthy volunteers, the peptide was absorbed slowly, with a maximum concentration reached after about 7 hours. Following daily multiple subcutaneous injections of rhIGF-I, 40 μg/kg, trough concentrations of IGF-I were increased by 277 ± 50 μg/l (mean ± SD) from baseline. IGF-I was thus characterized as a low-clearance peptide, with a clearance and half-life estimated at about 0.20 ml/minute/kg and 20 hours, respectively, in healthy volunteers. The volume of distribution was low, about 0.20–0.36 litres/kg, the bioavailability of subcutaneously administered rhIGF-I was 100%, and the rate of production of IGF-I was estimated to be about 50 μg/kg/day (3.5 mg/day). Patients with GHRD had low baseline IGF-I concentrations (30–50 μ g/ l) and a much more rapid turnover of IGF-I compared with that in healthy volunteers. The clearance and half-life of IGF-I were estimated to be about 0.60 ml/minute/kg and 6 hours, respectively. The volume of distribution was about the same as in healthy subjects. Due to the rapid turnover of IGF-I, trough IGF-I concentrations were increased to just above baseline during subcutaneous injections of 40 μg/kg once daily for 7 days. The maximum increase in IGF-I levels was 111 ± 12 μg/l and 150 ± 3 μg/l following daily subcutaneous injections of 40 × 1 and 40 × 2 μg/kg for 7 days, respectively.     

Leptin levels in children with insulin dependent diabetes mellitus

Leptin, a product of the ob gene, is a polypeptide hormone produced in adipose tissue that informs the brain about the amount of energy storage of body fat. It has very important effects on neuroendocrine functions and energy expenditure. The aim of our study was to determine leptin levels of children with insulin dependent diabetes mellitus (IDDM), which is known to affect body metabolism, and to investigate the relationship between duration of the disease, insulin dosage, HbA1c levels, body mass index (BMI), serum lipids and IGF-1 levels. Sixteen patients with IDDM (chronological age 13.8 +/- 2.6 years) whose HbAlc levels were 10.2 +/- 1.9 %, BMI 21.2. +/- 2.7 kg/m2, insulin dosage 0.9 +/- 0.4 U/kg/day and duration of the disease 6.7 +/- 2.6 years, and 12 healthy controls (13.4 +/- 2.6 years) were included in the study. Fasting plasma leptin levels were measured by radioimmunoassay method. The mean plasma leptin levels of the patient and the control groups were 19.1 +/- 7.6 ng/ml and 6.1 +/- 2.9 ng/ml, respectively, and significant difference was found between the two groups (p < 0.05). No correlation was found between leptin values and IGF-1, cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride levels, atherogenic index, insulin dosage or HbA1c levels in the patient group. A weak statistical correlation was determined between BMI and leptin levels in the IDDM group (r = 0.28, p < 0.05). A positive correlation was also found between leptin levels and the duration of the disease (r = 49, p < 0.05). As a result, it seems that leptin levels of children with IDDM differed from the levels of the control group significantly, and that the duration of insulin therapy was responsible for this difference.     

Growth hormone-IGF-I axis and growth velocity in Chinese children with type 1 diabetes mellitus

OBJECTIVE: To elucidate hormonal disturbances in patients with type 1 diabetes mellitus (DM1) with and without growth retardation. METHODS: Patients with DM1 were divided into two groups, group A consisted of 14 patients with poor growth, and group B consisted of 24 patients with normal growth. Serum IGF-I, IGFBP-3, basal and stimulated GH, and HbA1c were measured. RESULTS: Serum IGF-I and IGFBP-3 concentrations were significantly decreased in group A versus both groups B and controls in Tanner stages I-III; in addition, these measurements in group B were significantly lower compared to controls in Tanner stages II and III, but there was no significant difference in prepuberty. Both basal and peak serum GH were attenuated significantly in group A versus group B. Basal serum GH in group B (normal growth DM1) was significantly elevated versus the controls. There was an unambiguous negative linear regression between IGF-I and mean HbA1c in patients with DM1. CONCLUSIONS: Growth retardation in patients with DM1 is associated with an abnormal GH-IGF-I axis and poor glycemic control.     

Exercise training and glycemic control in adolescents with poorly controlled type 1 diabetes mellitus

This study sought to establish whether the glycemic control achieved in exercise-trained adolescents with type 1 diabetes mellitus (DM) is dependent on the quality of glycemic control prior to the initiation of exercise training. Adolescents with type 1 DM were randomly assigned to groups with either lower or higher than 9% glycosylated hemoglobin (HbA1c), and submitted to 12 weeks of supervised training followed by 12 weeks of unsupervised training (n = 12 per group). Supervised training caused a 17% rise in the patients' aerobic capacity which during the ensuing period of unsupervised training decreased to pre-training levels, thus suggesting a poor compliance with unsupervised training. The average levels of HbA1c in poorly and well controlled diabetic patients were not affected by training, a finding indicating that irrespective of the quality of glycemia prior to exercise training, glycemic control in adolescents with type 1 DM does not improve in response to exercise training alone.     

Response of circulating ghrelin levels to insulin therapy in children with newly diagnosed type 1 diabetes mellitus

Ghrelin is secreted primarily by the stomach, although other tissues such as the pancreas synthesize a minor proportion. The discovery of a new cell type that produces ghrelin in the human pancreas and that this organ expresses GHS-R opens new perspectives in the understanding of the control of glucose metabolism. We have studied 22 children with newly diagnosed type 1 diabetes mellitus at four different points: at diagnosis before insulin therapy, after 48-60 h of insulin therapy, and after 1 and 4 mo of insulin treatment. At each point circulating levels of ghrelin, leptin, IGF-I, IGF binding protein (IGFBP)-1, IGFBP-2, IGFBP-3, and glucose were determined. Ghrelin levels were significantly decreased at diagnosis (573 +/- 68 pg/mL, p < 0.01) compared with controls (867 +/- 38 pg/mL) and remained decreased after insulin therapy (d 2: 595 +/- 68 pg/mL; 1 mo: 590 +/- 61 pg/mL; 4 mo: 538 +/- 67 pg/mL) with no differences before or after insulin treatment. There was a negative correlation between ghrelin levels and body mass index at all of the study points, whereas a negative correlation between ghrelin and glucose concentrations was only observed after insulin therapy. No correlation between ghrelin and HbA1c was found at any point. A positive correlation between ghrelin and IGFBP-1 was found after insulin therapy, but no correlation with other members of the IGF system or leptin was found. In conclusion, these data could indicate a possible link between glucose concentrations and ghrelin; hence, the persisting low ghrelin levels in diabetic children may suggest a defensive mechanism against hyperglycemia.     

The relationship of the levels of leptin, insulin-like growth factor-I and insulin in cord blood with birth size, ponderal index, and gender difference

In humans, serum levels of leptin correlate with total body fat in both adults and children. After collecting cord blood from 156 term neonates (82 males, 74 females; 132 AGA and 22 LGA), we measured the cord levels of leptin, insulin and IGF-I to determine the relationships between these three hormones and relationships of these hormones with birth size (birth weight and ponderal index for adiposity in newborn) and gender. The leptin and IGF-I levels were significantly higher in the LGA group (9.2+/-4.0 ng/ml and 96.1+/-34.1 ng/ml, respectively) than in the AGA group (4.8+/-3.8 ng/ml and 56.4+/-37.6 ng/ml, respectively). A significant positive correlation was observed between leptin levels and birth weight, and a weaker correlation between leptin levels and birth height. IGF-I level significantly correlated with birth weight and birth height, but there was no correlation between the levels of insulin and birth weight. There was no relationship between the levels of IGF-I, insulin and leptin. Ponderal index was higher in LGA than in AGA. A significant correlation was also observed between the levels of leptin and ponderal index, but not between the levels of insulin or IGF-I and ponderal index. The levels of leptin and ponderal index were higher in females than males despite no gender differences in gestational age and birth weight. In conclusion, our results suggest that the level of IGF-I is a useful index for fetal growth during late gestation, and the development of adipose tissue is the major determinant of fetal serum leptin levels, the production of which is not regulated by insulin or IGF-I. In addition, a gender difference with a higher level of leptin in female neonates suggests that sexual dimorphism in adipose tissue already exists in utero.     

Insulin and Leptin Levels in Appropriate-for-Gestational-Age Infants of Diabetic Mother

Objective

Intensified management of gestational diabetes mellitus can normalize birth weight. However, it is still unknown whether intrauterine exposure to maternal diabetes is a risk factor for changing hormone levels involved in the development of insulin resistance in these infants. We compared insulin and leptin levels in appropriate for gestational age (AGA) infants of diabetic and non diabetic mothers.

Methods

We performed a cross-sectional study in the department of Neonatology of the Hospital of Gynecology-Pediatrics, in Leon, Mexico. We evaluated 182 full term AGA newborns (86 infants of diabetic and 96 of non-diabetic mothers). A venous blood sample was taken from cord blood immediately after the separation of the placenta and glucose, insulin and leptin levels were measured. In all diabetic mothers HbA1c was also evaluated immediately post-partum.

Findings

Leptin, insulin and insulin resistance index were significantly higher in infants of diabetic mothers. Leptin levels were positive correlated with insulin, parents‘ body mass index and age in the entire group. In infants of diabetic mothers only insulin levels showed a significantly correlation, whereas in those of non-diabetic mothers only mothers‘ age was significantly correlated with leptin levels.

Conclusion

AGA infants of diabetic mothers showed higher leptin, insulin levels and insulin resistance index than those of non-diabetic mothers.     

Insulin requirement in preschoolers treated with insulin pumps at the onset of type 1 diabetes mellitus

The aim: The aim of this study is to analyze changes in the basal insulin requirement in preschoolers treated with insulin pump at the onset of T1DM, using system to calculate meal time insulin.
Methods: 58 children (31 girls) under 6 years (mean age 3.3 ± 1.5 years) initiated on insulin pump therapy within 2 months after recognition of T1DM and treated at least for 1 year were analyzed during a follow-up period of 165 patient-years. Data was collected every 6 months: HbA1c, BMI SDS, diabetic ketoacidosis, severe hypoglycaemia, total daily insulin dose (TDD) and basal insulin.
Results: Basal insulin rose from 10% in the third month and did not exceed 30% of TDD after 12 months (p<0.0001). In the third month, 46% of children were without basal insulin; this group included significantly older children (3.7 ± 1.4 vs. 2.8 ± 1.4 years; p = 0.01), which had lower TDD (0.33 ± 0.18 vs. 0.54 ± 0.23u/kg/d; p = 0.0007) than children with basal insulin. HbA1c persisted ≤7.3%.
Conclusion: In preschool children initiated on CSII therapy at the time of T1DM diagnosis the first year of treatment is critical for altering the basal insulin dose. Preschoolers with TDD lower than 0.5U/kg/d may not require basal insulin. Moreover, basal insulin did not exceed 30% of TDD in the first years after T1DM onset.     

1型糖尿病儿童血胰岛素样生长因子的变化

目的 探讨中国1型糖尿病病儿血胰岛素样生长因子－1（IGF－1）和胰岛素样生长因子结合蛋白－3（IGFBP－3）的变化。方法 糖尿病组46例,测定胰岛素治疗前、后血IGF－1、IGFBP－3等指标。对照组为正常儿童78例,测定空腹血IGF－1,IGFBP－3。结果 1．糖尿病组胰岛素治疗前血IGF－1和IGFBP－3均低于正常对照组,P＜0．01。经过胰岛素治疗,血IGF－1和IGFBP－3的水平随血糖水平的下降和C－肽水平的升高明显上升,仍低于对照组,P＜0．05。2．糖尿病组使用胰岛素治疗前血IGF－1和IGFBP－3分别与治疗前血糖浓度呈高度负相关关系,P＜0．05。胰岛素治疗前、后血IGF－1与血C－肽水平呈高度正相关关系,P＜0．05。结论 1型糖尿病病儿血IGF－1和TGFBP－3明显下降,青春期前血胰岛素和C－肽可能对IGF－1和IGFBP－3起主要调节作用。     

Leptin binding activity (LBA) in plasma of nondiabetic and diabetic adolescents and obese children: relation to auxologic and hormonal data

Leptin circulates in serum bound to high molecular weight proteins. Hypothesizing that leptin binding proteins may regulate the functional efficiency of leptin, we characterized auxologic and hormonal factors that influence leptin binding in three disparate groups: normal adolescents, obese children, and teenagers with type I diabetes mellitus (IDDM). Specific leptin binding activity (sLBA) was assessed by column chromatography after incubation of serum with 125I-leptin in the presence and absence of excess unlabeled leptin. Mean sLBA was 17.0 +/- 7% (SD) in the healthy adolescents (n=41), 6.6 +/-4.3% in the obese children (n=26), and 14.9 +/-7.3% in the diabetic teenagers (n=17). At any value of sLBA, obese children had higher serum leptin levels than non-obese adolescents or diabetic teenagers, consistent with "leptin resistance" in the obese group. sLBA was higher in males than in females only in those with diabetes (18.6 +/- 7.3 vs 10.9 +/- 5.1%, p<0.05). sLBA correlated inversely with serum insulin-like growth factor-I values in the normal group (r= -0.45, p<0.01) and with insulin in the obese children (r= -0.53, p<0.01). There was no correlation between sLBA or serum leptin values and HbA1c, in the diabetic group. The serum leptin concentration was the principal determinant explaining the total variability of sLBA in all three cohorts. However, body mass index (BMI = weight/ height2) accounted for more of the total variability of percent specific binding in the healthy adolescents than in the other groups. We conclude that sLBA reflects circulating leptin levels, body composition, and hormonal milieu. Thus, in addition to leptin, qualitative and quantitative characteristics of leptin binding may play a physiological role in the regulation of appetite and in the "leptin resistance" of obesity.     

儿童I型糖尿病青春发育前及青春期血清IGF-I和IGFBP-3水平监测

目的：研究儿童Ⅰ型糖尿病青春发育前及青春期血清胰岛素样生长因子I(IGF-I),胰岛素样生长因子结合蛋白3(IGFBP-3)水平变化,探讨生长激素 胰岛素样生长因子I(GH-IGF-I)轴与血糖控制的关系。方法：分别采用ELISA和免疫放射法测定63例Ⅰ型糖尿病患儿和47例正常对照血清IGF-I,IGFBP-3水平,用胶乳凝集法测定Ⅰ型糖尿病患儿的糖化血红蛋白(HbAIC)。结果：①青春发育前糖尿病患儿血IGF-I为(75.4±26.6) ng/ml,IGFBP-3为(2 756.1±763.8) ng/ml,与对照组［(103.9±46.5) ng/ml,(2 717.1±480.2 ng/ml)相比无统计学差异(P>0.05);但青春期糖尿病患儿血IGF-I和IGFBP-3［(178.2±65.9) ng/ml,(2 956.0±847.6) ng/ml］均低于对照组［(229.6±54.5) ng/ml,(3 393.2±748.9) ng/ml］］P<0.05。②新发病的I型糖尿病患儿胰岛素治疗后血IGF-I为(143.0±67.5) ng/ml,IGFBP-3为(2 740.0±449.8) ng/ml,较治疗前［(54.8±44.3) ng/ml, (2 233.8±336.2) ng/ml］明显升高(P<0.05)。③糖尿病组HbA IC与血IGF-I,IGFBP-3之间存在负相关关系(r=-0.32,-0.29,P<0.01或0.05)。④糖尿病组青春期HbAIC为(9.0±1.8)%,每日胰岛素用量为(0.86±0.30)U/kg,均高于青春期前［(7.8±1.8) %,(0.64±0.38) U/kg］(P<0.05)。结论：儿童Ⅰ型糖尿病血IGF-I,IGFBP-3水平较正常儿降低,尤其青春期患儿比正常同龄儿降低的程度更为显著,提示此类患者青春期存在GH IGF-I轴的严重紊乱,可能是导致这一时期血糖控制不良的重要原因。     

Insulin-like growth factor binding protein-1 as glucose regulator in adolescent boys with type 1 diabetes

The aim of the present study was to investigate whether the diurnal variability of B-Glucose is dependent on GH, IGF-I and IGFBP-1 levels, apart from insulin, and if there is any difference between Tanner stages 3 and 5. Five boys in Tanner stage 3 and 6 boys in stage 5 with type 1 diabetes were included. Blood was continuously collected from a cubital vein for 24 h. S-Insulin, S-GH, S-IGF-I and S-IGFBP-1 were analysed. B-Glucose was analysed hourly at bedside. One week before and 1 wk after the 24-h study period the participants performed self-monitoring of blood glucose (SMBG) during normal physiologic conditions. In the 24-h profile of B-Glucose, insulin, IGFBP-1 and GH, we found a significant positive correlation between B-Glucose and log IGFBP-1 (r = 0.5, p = 0.005) and an inverse correlation to insulin (r = -0.5, p = 0.004) but no correlation to logGH (r = -0.04, p = 0.831). In multiple regression analysis, B-Glucose was still significantly correlated to log IGFBP-1, when adjusting for insulin and GH, in Tanner stage 5. We found a difference between Tanner stages 3 and 5 in the variability of B-Glucose over a longer period during normal daily activity (p = 0.02), but not over the 24-h study period. CONCLUSION: We have demonstrated in type 1 diabetes adolescent boys a relationship between simultaneously measured blood-glucose and IGFBP-1 levels independent of the insulin and GH levels, suggesting that the free fraction of IGF-I influences the glucose metabolism.