Pharmacogenomics of insulin-like growth factor-I generation during GH treatment in children with GH deficiency or Turner syndrome.

Individual responses to growth hormone (GH) treatment are variable. Short-term generation of insulin-like growth factor-I (IGF-I) is recognized as a potential marker of sensitivity to GH treatment. This prospective, phase IV study used an integrated genomic analysis to identify markers associated with 1-month change in IGF-I (ΔIGF-I) following initiation of recombinant human (r-h)GH therapy in treatment-naïve children with GH deficiency (GHD) (n=166) or Turner syndrome (TS) (n=147). In both GHD and TS, polymorphisms in the cell-cycle regulator CDK4 were associated with 1-month ΔIGF-I (P<0.05). Baseline gene expression was also correlated with 1-month ΔIGF-I in both GHD and TS (r=0.3; P<0.01). In patients with low IGF-I responses, carriage of specific CDK4 alleles was associated with MAPK and glucocorticoid receptor signaling in GHD, and with p53 and Wnt signaling pathways in TS. Understanding the relationship between genomic markers and early changes in IGF-I may allow development of strategies to rapidly individualize r-hGH dose.

Behaviour and metabolic control in children with Type 1 diabetes mellitus on insulin pump therapy: 2-year follow-up.

AIMS: This study investigated whether continuous subcutaneous insulin infusion is associated with sustained improvement in behaviour and metabolic control. METHODS: Children with Type 1 diabetes mellitus (n = 27, 8-18 years old) who had been assessed previously prior to commencing continuous subcutaneous insulin infusion, and 6-8 weeks later, were re-evaluated 2 years after commencing insulin pump therapy. Behaviour was reassessed using the Behavioral Assessment System for Children-2nd edition (BASC-2) and current HbA(1c) levels were recorded. RESULTS: Two years after commencing continuous subcutaneous insulin infusion, parent-reported internalizing and externalizing symptoms were significantly lower than pre-insulin pump therapy commencement levels. Self reports of internalizing and externalizing problems did not differ significantly across the three assessment points. There was no significant difference between pre-insulin pump therapy HbA(1c) and HbA(1c) after 2 years on continuous subcutaneous insulin infusion, despite an initial improvement 6-8 weeks after commencing the therapy. CONCLUSIONS: Children with Type 1 diabetes mellitus showed sustained improvements in parent-reported behaviour, but not in self reports of behaviour or in metabolic control 2 years after commencement of continuous subcutaneous insulin infusion.

Improvements in cognition, mood and behaviour following commencement of continuous subcutaneous insulin infusion therapy in children with type 1 diabetes mellitus: a pilot study.

AIMS/HYPOTHESIS: Anecdotally, parents and teachers of children with type 1 diabetes mellitus report improvements in behaviour and learning following the commencement of continuous subcutaneous insulin infusion (CSII). This study aimed to investigate changes in cognition, mood and behaviour following commencement of CSII in children with type 1 diabetes. METHODS: Children (n = 32) with type 1 diabetes aged 6-16 years and starting CSII at two Australian centres underwent behavioural, cognitive and glycaemic assessments prior to the commencement of CSII and 6-8 weeks after its start. A comprehensive cognitive test battery was administered, comprising measures of intelligence, attention, processing speed and executive skills. Behaviour and mood were assessed using the Behaviour Assessment System for Children--Second Edition. Continuous glucose monitoring was performed over a 72 h period and HbA(1c) was measured at both time-points. RESULTS: After commencement of CSII, there were significant improvements in HbA(1c), a reduction in hyperglycaemia and blood glucose variation and an increase in normoglycaemia. Significant improvements were observed in perceptual reasoning, selective attention, divided attention, cognitive flexibility and working memory. Fewer mood-related symptoms were reported (parent, teacher and self-report) and fewer behavioural problems (parent reports) CONCLUSIONS/INTERPRETATION: In this uncontrolled pilot study, children with type 1 diabetes demonstrated significant improvements in measures of metabolic control, mood and behaviour and in some complex cognitive skills after commencing CSII therapy.

Glycaemic impact of patient-led use of sensor-guided pump therapy in type 1 diabetes: a randomised controlled trial.

AIMS/HYPOTHESIS: The objective of this study was to assess the impact of patient-led sensor-guided pump management on glycaemic control, and compare the effect with that of standard insulin pump therapy. METHODS: An open multicentre parallel randomised controlled trial was conducted at five tertiary diabetes centres. Participants aged 13.0-40.0 years with well-controlled type 1 diabetes were randomised 1:1 to either study group for 3 months. Randomisation was carried out using a central computer-generated schedule. Participants in the intervention group used sensor-guided pump management; no instructive guidelines in interpreting real-time data were provided ('patient-led' use). Participants in the control group continued their original insulin pump regimen. Continuous glucose monitoring (CGM) and HbA(1c) level were used to assess outcomes. The primary outcome was the difference in the proportion of time in the target glycaemic range during the 3 month study period (derived from CGM, target range 4-10 mmol/l). Secondary outcomes were difference in HbA(1c), time in hypoglycaemic (< or =3.9 mmol/l) and hyperglycaemic (> or =10.1 mmol/l) ranges and glycaemic variability. RESULTS: Sixty-two participants were recruited and randomised; 5/31 and 2/31 withdrew from intervention and control groups, respectively, leaving 26/31 and 29/31 for the intention-to-treat analyses. When adjusted for baseline values, the mean end-of-study HbA(1c) was 0.43% lower in the intervention group compared with the control group (95% CI 0.19 to 0.75%; p = 0.009). No difference was observed in CGM-derived time in target (measured difference 1.72; 95% CI -5.37 to 8.81), hypoglycaemic (0.54; 95% CI -3.48 to 4.55) or hyperglycaemic (-2.18; 95% CI -10.0 to 5.69) range or in glycaemic variability (-0.29; 95% CI -0.34 to 0.28). Within the intervention group, HbA(1c) was 0.51% lower in participants with sensor use > or =70% compared with participants with sensor use <70% (95% CI -0.98 to -0.04, p = 0.04). Five episodes of device malfunction occurred. CONCLUSIONS/INTERPRETATION: Individuals established on insulin pump therapy can employ sensor-guided pump management to improve glycaemic control. An apparent dose-dependent effect of sensor usage was noted; however, frequent use of this technology (> or =70%) was not universally acceptable. TRIAL REGISTRATION: ACTRN12606000049572

Safety and efficacy of the predictive low glucose management system in the prevention of hypoglycaemia: protocol for randomised controlled home trial to evaluate the Suspend before low function.

INTRODUCTION: Innovations with sensor-augmented pump therapy (SAPT) to reduce hypoglycaemia in patients with type 1 diabetes are an ongoing area of research. The predictive low glucose management (PLGM) system incorporates continuous glucose sensor data into an algorithm and suspends basal insulin before the occurrence of hypoglycaemia. The system was evaluated in in-clinic studies, and has informed the parameters of a larger home trial to study its efficacy and safety in real life. METHODS AND ANALYSIS: The aim of this report is to describe the study design and outcome measures for the trial. This is a 6-month, multicentre, randomised controlled home trial to test the PLGM system in children and adolescents with type 1 diabetes. The system is available in the Medtronic MiniMed 640G pump as the 'Suspend before low' feature. Following a run-in period, participants are randomised to either the control arm with SAPT alone or the intervention arm with SAPT and Suspend before low. The primary aim of this study is to evaluate the time spent hypoglycaemic (sensor glucose <3.5 mmol/L) with and without the system. The secondary aims are to determine the number of hypoglycaemic events, the time spent hyperglycaemic, and to evaluate safety with ketosis and changes in glycated haemoglobin. The study also aims to assess the changes in counter-regulatory hormone responses to hypoglycaemia evaluated by a hyperinsulinaemic hypoglycaemic clamp in a subgroup of patients with impaired awareness. Validated questionnaires are used to measure the fear of hypoglycaemia and the impact on the quality of life to assess burden of the disease. ETHICS AND DISSEMINATION: Ethics committee permissions were gained from respective Institutional Review boards. The findings of the study will provide high quality evidence of the ability of the system in the prevention of hypoglycaemia in real life. TRIAL REGISTRATION NUMBER: ACTRN12614000510640, Pre-results.

Improvement of doxorubicin induced cardiomyopathy in rats treated with insulin-like growth factor I.

OBJECTIVES: This study was designed to assess the effects of treatment with insulin-like growth factor-I (IGF-I) on cardiac function and structure in rats with an established cardiomyopathy. METHODS: Adult male Wistar rats were injected with doxorubicin (2 mg.kg-1 subcutaneously) weekly for 12 weeks and either rhIGF-I (0.8 mg.kg-1.day-1; n = 16, D-I group) or saline (n = 25, D-S group) subcutaneously via an osmotic pump from weeks 9 to 12. A non-doxorubicin injected control group was also studied. After 12 weeks survivors were anaesthetised and cardiac output determined with radiolabelled microspheres. At postmortem pleural effusion and ascitic volumes were measured and the heart was removed for histological examination by light and transmission electron microscopy. RESULTS: Doxorubicin treated animals showed less mean weight gain from week 2 than the untreated control group. Animals treated with IGF-I from week 9 showed a significant (p < 0.05) but non-sustained increase in weight. Survival to 12 weeks was 56% in the D-I group and 44% in the D-S group (p = 0.2). Evidence of cardiac failure was seen in the D-I and the D-S groups, but there was a tendency (p = 0.06) for less ascites in the D-I group (21 (SEM 8) ml) than in the D-S group (46 (10) ml). Cardiac output was significantly higher in the D-I than in the D-S group (132 (7.2) v 91.4 (6.4) ml.min-1, p < 0.01), as was stroke volume (0.323 (0.03) v 0.226 (0.02) ml, p < 0.01). There was focal cardiac damage in both D-I and D-S animals. Scattered groups of myocytes showed prominent vacuolation of the nuclear envelope, sarcoplasmic reticulum, and t tubular system, mild to severe mitochondrial swelling, and loss of orientation and definition of myofibrils. No clear morphological differences were evident between the two groups. CONCLUSIONS: Administration of IGF-I may improve the function of damaged myocardium, although the mechanisms are unclear. Further studies with earlier coadministration of IGF-I, quantitative histological analysis, and with other models of cardiac injury are indicated.

Ovine placental lactogen is a potent somatogen in the growth hormone (GH)-deficient rat: comparison of somatogenic activity with bovine GH.

The somatogenic effects of recombinant ovine placental lactogen (oPL) were investigated in the GH-deficient dwarf rat and compared to those of identical doses of recombinant bovine GH (bGH) in three independent studies. Both oPL and bGH treatments resulted in an increase (P less than 0.05) in body weight gain compared to that in saline controls, with oPL treatment being more potent than bGH (P less than 0.05). In promoting linear growth, oPL was more potent (P less than 0.05) than bGH in some instances. The nitrogen content of dry carcass matter was increased with oPL treatment compared to saline (P less than 0.05), with a nonsignificant increase in bGH-treated animals. Carcass fat was similarly reduced by both oPL and bGH treatment (P less than 0.05) compared to saline. Serum insulin-like growth factor-I (IGF-I) concentrations were increased significantly (P less than 0.05) by both oPL and bGH treatments, with a significantly greater effect of oPL suggested in one study. No increase in hepatic IGF-I mRNA was evident with either treatment, suggesting that the increase in serum IGF-I is due to posttranscriptional mechanisms. The expression of IGF-binding protein-3 hepatic mRNA was increased (P less than 0.05) with bGH treatment compared to that after saline treatment, but was unaffected by oPL treatment, indicating regulation by GH at the transcriptional level. The binding of [125I]bGH to hepatic membrane preparations demonstrated no difference in specific binding compared to that in saline controls. However, [125I]oPL specific binding was greater in oPL-treated animals (P less than 0.05). Animals treated with bGH had reduced (P less than 0.05) hepatic GH receptor mRNA compared to saline controls, but oPL treatment had no effect. Thus, oPL is a potent anabolic and lipolytic agent in the dwarf rat, exerting greater somatogenic effects on some parameters than bGH. Our data suggest differences in receptor binding and effects on GH receptor and IGF-binding protein-3 expression with these two treatments, raising the possibility of actions through different pathways or differential effects at the GH receptor level.

Characterization of ovine growth hormone (oGH) and ovine placental lactogen (oPL) binding to fetal and adult hepatic tissue in sheep: evidence that oGH and oPL interact with a common receptor.

The GH receptor (GHR) plays a key role in postnatal growth regulation. Although plasma concentrations of GH are high during fetal life, its role during fetal development is not well understood. Recent data suggest that GHR are present in fetal hepatic tissue as early as 51 days gestation. However, the levels of GHR expression are markedly lower in fetal hepatic tissue compared to postnatal values, and there are conflicting data suggesting that ovine placental lactogen (oPL) and oGH share a common receptor. Given the uncertainty about whether oPL acts via the oGHR or a distinct receptor, we performed ligand binding and affinity cross-linking studies on hepatic microsomal membranes from adult castrated male, pregnant female, and fetal sheep. Ligand binding assays at a constant concentration of membranes showed that [125I]oPL yielded consistently higher (P < 0.001) specific binding (59.5 +/- 6.4%, 30.5 +/- 5.7%, and 7.6 +/- 2.4% for castrated male, pregnant female, and fetal sheep, respectively) compared to [125I]oGH (17.8 +/- 4.7%, 5.0 +/- 1.6%, and 1.2 +/- 0.4% for castrated male, pregnant female, and fetal sheep, respectively). Cross-reactivity studies showed that unlabeled oPL was consistently more potent than unlabeled oGH in displacing either of the labeled ligands. The dissociation constant (Kd) for oPL binding ranged from 0.16-0.40 nM and was not changed by solubilization with Triton X-100. Equilibrium binding analysis for oGH showed lower affinity for hepatic microsomal membranes (Kd, 1.7-3.2 nM) in each of the three groups of animals. Affinity cross-linking of microsomal membranes from castrated male and pregnant female sheep liver showed four major cross-linked complexes with both [125I]oPL and [125I]oGH, with mol wt of 150, 97, 75, and 60 kilodaltons. All four bands were identified with both ligands. Unlabeled oPL showed markedly higher potency than unlabeled oGH in reducing the signal of the [125I]oPL cross-linked complexes, whereas unlabeled oGH and oPL showed comparable potencies in reducing the signal of the [125I]oGH complexes. Immunoprecipitation of detergent-solubilized hepatic microsomal membranes from pregnant and fetal sheep using a panel of monoclonal antibodies raised against the extracellular region of the rabbit GHR showed potent immunological recognition of the [125I]oPL-receptor complexes. We suggest that oGH and oPL bind to a common or a related receptor protein(s). It is possible that differences in receptor dimerization or association with other membrane proteins are the basis of the differences in affinity and biological actions of the two hormones.

Presence of insulin-like growth factor-I receptors and absence of growth hormone receptors in the antler tip.

Red deer antler tips in the growing phase were removed 60 days after the recommencement of growth for autoradiographical studies and RRAs. Sections were incubated with radiolabeled GH or insulin-like growth factor-I (IGF-I), with or without excess competing unlabeled hormones, and were analyzed autoradiographically. There was negligible binding of [125I]GH in any histological zone of antler sections. [125I]IGF-I showed highest specific binding in the chondroblast zone to a receptor demonstrating binding characteristics of the type 1 IGF receptor. The lowest specific binding of [125I]IGF-I was to prechondroblasts. RRAs on antler microsomal membrane preparations RRAs on antler microsomal membrane preparations confirmed the absence of GH receptors and the presence of type 1 IGF receptors found by autoradiography. These findings suggest that IGF-I may act in an endocrine manner in antler growth through a receptor resembling the type 1 IGF receptor. The presence of type 1 receptors in the chondroblast zone implicates IGF-I involvement in cartilage formation through matrixogenesis. There is no support for IGF-I having a major role in mitosis in the antler.

The induction of hepatic somatotrophic receptors after birth in sheep is dependent on parturition-associated mechanisms.

While the GH receptor (GHR) plays a key role during adult life, its role during fetal development is not well understood. Recent data suggest that GHRs are present in ovine fetal hepatic tissue at mid-gestation. However, the levels of GHR expression are markedly lower in fetal hepatic tissue in comparison with postnatal values. The present study investigates whether the neonatal induction of the hepatic GHR and plasma levels of IGF-I follow a pattern of strictly age-related development or whether birth-associated processes stimulate this increase. Stereotaxic electrolytic lesioning of the fetal paraventricular nuclei was employed to prolong gestation markedly. We compared the hepatic binding of ovine placental lactogen (oPL) and oGH and plasma levels of IGF-I in these post-mature fetuses with those in pre-term fetuses, pregnant mothers and lambs which were of the same conceptional age as the post-mature fetuses. While specific binding of both 125I-labelled oGH and 125I-labelled oPL to hepatic microsomal membranes was fully reversible in all groups, the specific binding of 125I-labelled oGH was significantly (P < 0.001) lower than specific binding of 125I-labelled oPL in all groups of animals. There was no difference in specific 125I-labelled oGH or 125I-labelled oPL binding in livers or plasma levels of IGF-I in post-mature fetuses in comparison with pre-term fetuses. In contrast, a major increase (P < 0.001) in 125I-labelled oGH and 125I-labelled oPL binding and plasma IGF-I levels was observed in lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of octreotide on GH receptor and IGF-I expression in the GH-deficient rat.

Somatostatin has been suggested to influence the somatotrophic axis outside the central nervous system, in reducing GH-induced IGF-I mRNA and IGF-I generation. This study aimed to determine whether such effects were mediated via the GH receptor (GHR). GH-deficient dwarf rats aged 45-47 days (n = 8 per group) received twice daily subcutaneous injections of octreotide (1 mg/kg) (group O), saline (group S), octreotide (1 mg/kg) plus bovine GH (0.25 mg/kg) (group OG), or bovine GH (0.25 mg/kg) plus saline (group G) for 10 days. Octreotide-treated animals had less weight gain compared with saline-treated animals, but not when GH cotreated (group OG vs G). Octreotide had an overall effect on decreasing length gain (P < 0.01). Serum IGF-I (ng/ml) was reduced by octreotide (group O 171 +/- 11, group S 239 +/- 20, P < 0.01; group OG 283 +/- 30, group G 362 +/- 10, P < 0.001), as was serum insulin (P < 0.001). A significant decrease in hepatic and muscle IGF-I mRNA expression was found as expected, yet this was not associated with decreased hepatic GHR expression. Rather, an increase in hepatic 125I-bovine GH specific binding was observed (P < 0.001) and, in GH-cotreated animals (OG), hepatic GHR and GH binding protein (GHBP) mRNA expression were also increased by octreotide by approximately 40%. In muscle, octreotide was associated with an approximately 30% decrease in GHBP mRNA and no effect on GHR mRNA. This study suggests that the suppressive effects of octreotide on IGF-I metabolism, at least in liver, are not mediated via down-regulation of GHR expression, but more likely by direct effects on IGF-I expression.

IGF-I and IGF-binding protein-3 in plasma of GH-deficient rats.

The majority of IGF-I circulates in a large (150 kDa) ternary complex with IGF-binding protein-3 (IGFBP-3) and a non-IGF-binding acid-labile subunit. The secretion of ternary complex into the circulation from liver has been considered to be GH-dependent; however, recent data indicate that GH does not directly regulate hepatic IGFBP-3 synthesis. To examine the role of insulin in regulating plasma IGFBP-3 levels, postpubertal male GH-deficient (dw/dw) rats were treated every 8 h with injections (s.c.) of 0.9% saline, 20 micrograms insulin/day, 200 micrograms hIGF-I/day, or 20 micrograms insulin/day plus 200 micrograms hIGF-I/day, for 10 days with the animals being killed 2-3 h after the final injection. Hypoglycaemia was not observed in any of the treatment groups. hIGF-I treatment increased longitudinal growth and weight gain (P < 0.05), while insulin treatment had no effect. Plasma IGF-I levels were increased in groups treated with hIGF-I (P < 0.05), while insulin treatment resulted in a reduction (P < 0.05): saline = 267.1 +/- 15.6 (ng/ml +/- S.E.M.), insulin = 219.3 +/- 17.5, hIGF-I = 391.7 +/- 17.6, insulin plus hIGF-I = 357.5 +/- 31.8. Hepatic IGF-I mRNA expression was increased in insulin-treated dw/dw rats in comparison with hIGF-I-treated animals (P < 0.05) but not in comparison with saline control or the combined treatment groups. Plasma levels of intact IGFBP-3, measured by ligand blot analysis, were increased in all treatment groups compared with saline (P < 0.05): saline = 100.0 +/- 9.4% (% of saline +/- S.E.M.), insulin = 149.9 +/- 17.5%, hIGF-I = 191.4 +/- 17.3%, insulin plus hIGF-I = 205.4 +/- 15.3%. The levels of the 28/32 kDa IGFBPs and IGFBP-4 in plasma were increased by hIGF-I treatment (P < 0.05) but not by insulin treatment. Hepatic specific 125I-bovine GH binding was not significantly different in any of the treatment groups. This study provides the first evidence in nondiabetic animals that insulin regulates hepatic IGF-I mRNA expression, plasma IGF-I and plasma IGFBP-3 levels in the GH-deficient state without changes in hepatic GH receptors. The divergent response of plasma IGF-I and IGFBP-3 levels to insulin treatment in the present study may indicate an effect of insulin on the clearance of IGF-I from the circulation.

Elevating maternal insulin-like growth factor-I in mice and rats alters the pattern of fetal growth by removing maternal constraint.

Fetal growth is normally constrained by maternal factors. This constraint is demonstrated by the usual inverse linear relationship between litter size and mean fetal weight. Cross-breeding experiments between mice of lines selected for high or low plasma insulin-like growth factor (IGF-I) levels suggested that elevations in maternal IGF-I abolish (P less than 0.01) this constraining effect and reverse the usual positive relationship between fetal and placental size in late gestation. This was confirmed by treating mice and rats throughout pregnancy with IGF-I. In normal mice and in low IGF-I line mice treatment with IGF-I (10 micrograms 8-hourly s.c. from day 1 to 19 of pregnancy) abolished maternal constraint whereas 0.9% (w/v) NaCl treatment did not. In Wistar rats osmotic pumps were implanted to deliver IGF-I (1 microgram/g body weight per day), bovine GH (bGH; 0.6 microgram/g body weight per day) or saline from day 1 to 19 of pregnancy. IGF-I therapy but not bGH or saline abolished (P less than 0.01) maternal constraint and altered (P less than 0.01) the relationship between placental and fetal weight. When high or low IGF-I line mice embroys were transplanted into a normal line of mice, the expected negative relationship (P less than 0.05) between mean fetal weight and litter size was maintained. However, the embryos of the high line were heavier (P less than 0.05) than those from the low line irrespective of fetal number, suggesting a direct role for IGF-I in the regulation of fetal growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Receptors for insulin-like growth factor-II in the growing tip of the deer antler.

Insulin-like growth factor-II (IGF-II) binding in the growing tip of the deer antler was examined using autoradiographical studies, radioreceptor assays and affinity cross-linking studies. Antler tips from red deer stags were removed 60 days after the commencement of growth, and cryogenically cut into sections. Sections were incubated with radiolabelled IGF-II, with or without an excess of competing unlabelled IGF-II and analysed autoradiographically. Radiolabelled IGF-II showed high specific binding in the reserve mesenchyme and perichondrium zones, which are tissues undergoing rapid differentiation and cell division in the antler. Binding to all other structural zones was low and significantly (P < 0.001) less than binding to the reserve mesenchyme/perichondrium zones. Radioreceptor assays on antler microsomal membrane preparations revealed that the IGF-II binding was to a relatively homogeneous receptor population (Kd = 1.3 x 10(-10) mol/l) with characteristics that were not entirely consistent with those normally attributed to the type 2 IGF receptor. Tracer binding was partly displaceable by IGF-I and insulin at concentrations above 10 nmol/l. However, affinity cross-linking studies revealed a single band migrating at 220 kDa under non-reducing conditions, indicative of the type 2 IGF receptor. These results indicate that, in antler tip tissues, IGF-II binds to sites which have different binding patterns and properties from receptors binding IGF-I. This may have functional significance as it appears that, whilst IGF-I has a role in matrix development of cartilage, IGF-II may have a role in the most rapidly differentiating and proliferating tissues of the antler.

Growth hormone (GH) and insulin-like growth factor-I (IGF-I) treatment of the GH-deficient dwarf rat: differential effects on IGF-I transcription start site expression in hepatic and extrahepatic tissues and lack of effect on type I IGF receptor mRNA expression.

The rat IGF-I gene consists of six exons, with exons 3 and 4 forming a 'core' mature IGF-I coding region to which alternate 5' and 3' regions are spliced. Transcription occurs from four dispersed start sites (ss) approximately 382 (ss 1), approximately 343 (ss 2), approximately 245 (ss 3) and approximately 30-40 (ss 4) basepairs (bp) from the 3' end of exon 1, and from a region 50-70 bp from the 3' end of exon 2. The expression of ss mRNAs displays tissue-specific and ontogenic regulation. Alternate splicing of exon 5 produces E-peptide coding domain variants (Ea and Eb mRNAs), with the Eb form found predominantly in the liver. The regulation of IGF-I mRNA expression by GH and IGF-I in the GH-deficient dwarf (dw/dw) rat was investigated using antisense RNA probes in a solution hybridization RNase protection assay to detect leader exon and E domain variant mRNAs. GH treatment of dw/dw and normal Lewis rats increased the expression of all liver leader exon ss and E domain variants coordinately (1.6-1.9-fold increase, p < 0.01), although the increase observed in Eb transcripts was significantly higher in the dw/dw compared to the normal rat (p < 0.05). In kidney, GH treatment significantly increased exon 1 ss 3 and ss 4 transcripts by approximately 40% (p < 0.05). The expression of the other start sites was not affected by GH, suggesting that transcription factors may regulate start site usage independently. GH treatment was associated with a significant increase in IGF-I mRNA expression in skeletal muscle (p < 0.05) but not cardiac muscle or spleen. IGF-I treatment was associated with minor (approximately 20%) but significant (p < 0.05) reductions in IGF-I mRNA expression in the liver and kidney of dw/dw rats, suggesting that IGF-I can suppress IGF-I mRNA expression. IGF-I treatment did not affect IGF-I mRNA expression in cardiac and skeletal muscle of dw/dw rats. IGF-I receptor mRNA was detected in extrahepatic tissues only, and was not affected by either GH or IGF-I treatment. In summary, start site-specific regulation by GH was observed in kidney. GH increased IGF-I mRNA expression in muscle, kidney and liver, but had no effect in heart or spleen in the dw/dw rat. Our data suggest that systemic IGF-I can feedback on hepatic and renal IGF-I mRNA expression in the GH-deficient state.

Children with coeliac disease and insulin dependent diabetes mellitus--growth, diabetes control and dietary intake.

We aimed to assess the growth, diabetes control, dietary intake and compliance with a gluten-free diet in children with insulin dependent diabetes mellitus (IDDM) and coeliac disease in a major paediatric and adolescent diabetes clinic. Children with IDDM and biopsy-proven coeliac disease aged <18 years were included and compared with IDDM controls matched for age, sex and duration of diabetes. Twenty patients with coeliac disease and IDDM participated (15 female, age 7.4-17.3 yr), with two matched IDDM controls for each (age 6.9-17.4 yr). The prevalence of coeliac disease in this diabetes clinic population was 2.6%. All patients completed a 3 day food record (3DFR) and a 7 day food frequency questionnaire (FFQ) to assess dietary intake and gluten-free compliance. Diabetes control measured by HbA1c was not different between groups or compared to the overall clinic population (8.48 +/- 0.98% for coeliac patients vs 8.87 +/- 1.46 for IDDM controls vs 8.60 +/- 1.30 for overall clinic population aged 5.0-17.9 yr). Height, weight and BMI standard deviation scores were not different between coeliac patients and IDDM controls. No clinically significant differences were found in intake of energy, macronutrients or micronutrients. The proportion of energy intake from carbohydrate, protein and fat was within recommended ranges, except for a higher saturated fat intake. Only 30% of coeliac patients complied with a strict gluten-free diet, but growth parameters were unaffected by dietary compliance. Thus, we found that children and adolescents with coexisting IDDM and coeliac disease have normal growth, equivalent diabetes control and no differences in energy or nutrient intake compared to matched IDDM controls in our clinic population.

Factors predictive of response to growth hormone therapy in Turner's syndrome.

In Turner's syndrome there is marked heterogeneity of growth response to growth hormone (GH) therapy. The study aim was to identify pretreatment factors that influence response to GH therapy. The 70 subjects recruited were prepubertal, had not received sex steroids and had received 28 units/m2/week of GH for > or = 1 year. Pretreatment variables associated with the greatest improvement in height SDS (r2 = 0.58) were weight for length index (p = 0.0001), target height (p = 0.004), bone age delay (p = 0.008) and age (p = 0.04). In conclusion, during two years of GH therapy the best growth response occurred in girls who were younger, heavier, had a delayed bone age and tall parents. Height SDS as a continuous variable is the most effective measure of growth when considering pretreatment factors that may influence response to GH therapy.

A pharmacogenomic approach to the treatment of children with GH deficiency or Turner syndrome.

OBJECTIVE: Individual sensitivity to recombinant human GH (r-hGH) is variable. Identification of genetic factors contributing to this variability has potential use for individualization of treatment. The objective of this study was to identify genetic markers and gene expression profiles associated with growth response on r-hGH therapy in treatment-naïve, prepubertal children with GH deficiency (GHD) or Turner syndrome (TS). DESIGN: A prospective, multicenter, international, open-label pharmacogenomic study. METHODS: The associations of genotypes in 103 growth- and metabolism-related genes and baseline gene expression profiles with growth response to r-hGH (cm/year) over the first year were evaluated. Genotype associations were assessed with growth response as a continuous variable and as a categorical variable divided into quartiles. RESULTS: Eleven genes in GHD and ten in TS, with two overlapping between conditions, were significantly associated with growth response either as a continuous variable (seven in GHD, two in TS) or as a categorical variable (four more in GHD, eight more in TS). For example, in GHD, GRB10 was associated with high response (≥ Q3; P=0.0012), while SOS2 was associated with low response (≤ Q1; P=0.006), while in TS, LHX4 was associated with high response (P=0.0003) and PTPN1 with low response (P=0.0037). Differences in expression were identified for one of the growth response-associated genes in GHD (AKT1) and for two in TS (KRAS and MYOD1). CONCLUSIONS: Carriage of specific growth-related genetic markers is associated with growth response in GHD and TS. These findings indicate that pharmacogenomics could have a role in individualized management of childhood growth disorders.