Serum Insulin-like Growth factor-I Concentrations Research Articles

Stunting and wasting in neurological Wilson disease: Role of copper, zinc, and insulin-like growth factor-I.

Copper (Cu) and zinc (Zn) are important trace elements for the growth and development of children. In Wilson disease (WD), impaired Cu metabolism may affect growth. This study was conducted to evaluate the height and weight of children with neurological WD and correlate these with serum Cu, Zn, and insulin-like growth factor-I (IGF-I). This prospective cohort study was conducted in a tertiary care teaching institute. Children with neurologic WD were included. The height, weight, and body-mass index of each child were measured and categorized according to the revised national growth chart. Serum Cu, Zn, calcium, alkaline phosphatase, albumin, thyroid-stimulating hormone, and urinary-Cu were measured. Serum IGF-1 was measured by enzyme-linked immunosorbent assay. The relationship between height and weight with trace elements and IGF was analyzed using parametric or non-parametric tests. There were 52 children (5-18 years) with neurologic WD. Thirty-six (69.2%) children had normal height, 12 (23.1%) were tall, and 4 (7.7%) were stunted. Forty-six (88.5%) children had normal weight and six (11.5%) children were underweight. IGF-1 correlated with height, weight, duration of treatment, and serum Zn level. About 15.4% of children had stunting and/or wasting, which was associated with low levels of serum IGF-I, Zn, and calcium. Stunting and/or wasting occurs in 15.4% of children with neurologic WD and is associated with reduced serum IGF-I, Zn, and calcium concentration. Adjunctive Zn and calcium treatment may help in achieving normal growth.

Abomasal Nitrogen Flow Affects the Relationship between Dietary Nitrogen and Insulin-Like Growth Factor-I in Growing Lambs

Twelve abomasally cannulated wether lambs were fed isocaloric diets containing 9, 12 or 15% crude protein to determine insulin-like growth factor-I (IGF-I) responses to altered abomasal nitrogen flow and nitrogen status. Lambs were offered 1100 g/d of their respective diets. Voluntary feed consumption was not affected by nitrogen intake. Ruminal and total tract digestibilities of dry matter, organic matter and nitrogen increased linearly (P < 0.05) with increased dietary nitrogen. Abomasal flows of total, bacterial and rumen escape nitrogen increased (linear, P < 0.01), whereas dry matter and organic matter flows decreased (linear, P < 0.01). Total amino acid flow was greater (linear, P < 0.01) in lambs fed additional nitrogen due to increased (linear, P < 0.01) flows of essential and nonessential amino acids. Nitrogen retention and blood urea nitrogen increased linearly (P < 0.01). Serum IGF-I concentrations and relative hybridization intensity of hepatic IGF-I mRNA increased (linear, P < 0.05) as lambs consumed more nitrogen. Serum IGF-I and hepatic IGF-I mRNA were correlated positively (P < 0.05) with nitrogen intake and abomasal flows of nitrogen and various amino acids. These data provide evidence of a relationship between abomasal amino acid flow, as influenced by nitrogen intake, and hepatic gene expression and serum concentrations of IGF-I in growing lambs.

Combined Growth Hormone (GH) and Insulin-Like Growth Factor-I (IGF-I) Treatment is More Effective than GH or IGF-I Alone at Enhancing Recovery from Neonatal Malnutrition in Rats

The effect of hormonal therapy on enhancing recovery from neonatal malnutrition was assessed in rats. Malnutrition was induced by maternal food restriction (60% control intake) during lactation. On d 16 postpartum, restricted pups were refed by cross-fostering to control dams and were subcutaneously administered growth hormone (GH), insulin-like growth factor-I (IGF-I), GH + IGF-I or saline. At d 21, pups were weaned and continued hormonal treatments until d 39 postpartum. By d 39, body weight of GH (96% control) and GH + IGF-I- (98%) treated animals were normal, whereas IGF-I (88%) and saline- (85%) treated animals were still stunted. Hormone effectiveness was age dependent, with growth rates of GH + IGF-I-, IGF-I- and GH-treated pups being greatest between d 16 and 30, d 16 and 21 and after d 30, respectively. Protein accretion by d 39 was higher (P < 0.01) in GH and GH + IGF-I groups than saline- or IGF-I-treated groups. On d 39, serum IGF-I concentrations were as follows: GH + IGF-I > IGF-I > GH = saline (placebo), indicating that an elevated serum IGF-I was not required for GH-stimulated growth. Of the three hormonal treatments, GH + IGF-I therapy was most efficacious at promoting rapid and complete body weight recovery and supporting lean body mass accretion.

Tracking and Cumulative Lifetime Exposure to IGF-I in 6459 Healthy Individuals and in SGA Children Treated With GH.

Supraphysiological serum insulin-like growth factor-I (IGF-I) concentrations have been a matter of concern in children treated with GH because high IGF-I levels were associated with risk of later disease in former epidemiological studies. To determine whether a single IGF-I measurement reliably reflects lifetime IGF-I exposure we evaluated intraindividual longitudinal tracking of IGF-I and IGF-binding protein-3 (IGFBP-3) levels and we estimated cumulative lifetime exposure to IGF-I in healthy and GH-treated individuals. We included 6459 healthy participants (cross-sectional = 5326; longitudinal = 1133) aged 0-76 years (9963 serum samples) and 9 patients born small-for-gestational-age (SGA) with 238 serum samples during GH treatment. Intraindividual tracking of IGF-I and IGFBP-3 (SD score [SDS]) was determined by intraclass correlation coefficients (ICCs). Cumulative lifetime IGF-I exposure was estimated by area under the curve of the predicted SDS trajectory from 0 to 76 years. For IGF-I (SDS), ICCs were 0.50 (95% CI, 0.47-0.53) for male and 0.53 (0.50-0.56) for female participants. Lifetime IGF-I exposure was significantly higher in female (mean 12 723 ± 3691 SD) than in male participants (12 563 ± 3393); P = 0.02. In SGA children, treatment with GH increased the lifetime exposure to IGF-I from 9512 ± 1889 to 11 271 ± 1689, corresponding to an increase in lifetime IGF-I trajectory from -0.89 SD ± 0.57 to -0.35 SD ± 0.49. Because IGF-I and IGFBP-3 levels track throughout life, a single measurement reliably reflects lifetime exposure. GH therapy increased the lifetime exposure to IGF-I only slightly and it remained below the average lifetime exposure in the reference population.

Resistance training-induced improvement in physical function is not associated to changes in endocrine somatotropic activity in prefrail older adults

ContextResistance training improves muscle function in prefrail and frail elderly. The role of the somatotropic axis in this physiologic process remains unclear. Insulin-like growth factor I (IGF-I) and its associated proteins Insulin-like growth factor binding protein 3 (IGFBP3) and acid labile subunit (ALS) build a circulating ternary complex that mediates growth hormone (GH) effects on peripheral organs and can serve as a measure of endocrine somatotropic activity. ObjectiveThe aim of this study was to assess the association between resistance training-induced changes in physical performance and basal levels of IGF-I, IGFBP-3 and ALS in prefrail older adults. Methods69 prefrail community-dwelling older adults, aged 65 to 94 years, were randomly assigned to a 12-week period of strength or power training or to a control group. The study was registered at clinicaltrials.gov as NCT00783159. Serum concentrations of IGF-I, IGFBP-3 and ALS were measured at rest before and after the intervention. Hormonal differences were examined in relation to changes in physical performance assessed by the Short Physical Performance Battery (SPPB). ResultsWhile resistance training led to significant improvements in SPPB score it did not induce significant differences in somatotropic hormone concentrations. Pre- and post-intervention changes in IGF-I, IGFBP-3, ALS or IGF/IGFBP-3 molar ratio were not related to the intervention mode, even after adjustment for age, sex, nutritional status, as well as SPPB and hormone concentrations at baseline. ConclusionTraining-induced improvements in physical performance in prefrail older adults were not associated with significant changes in endocrine somatotropic activity.

Determination of Insulin-like Growth Factor I (IGF-I) in Serum by a Chemiluminescence Immunoassay (CLIA)

A high-performance chemiluminescence immunoassay (CLIA) has been established for the determination of insulin-like growth factor I (IGF-I) in human serum. This approach is dependent on a double antibody sandwich-complexation method to determine the concentration of IGF-I in serum. The results demonstrate that this method was able to determine IGF-I across a wide linear range from 5 to 1000 ng/mL. The limit of the blank was 0.022 ng/mL. The coefficient of variation (CV) was less than 7% for both intra-assay and inter-assay precision. The average recoveries were 109.4%, 98.8%, and 101.9%. This method offers excellent performance and provides a foundation for further clinical applications of serum IGF-I determination.

Associations between food group intakes and circulating insulin-like growth factor-I in the UK Biobank: a cross-sectional analysis

PurposeCirculating insulin-like growth factor-I (IGF-I) concentrations have been positively associated with risk of several common cancers and inversely associated with risk of bone fractures. Intakes of some foods have been associated with increased circulating IGF-I concentrations; however, evidence remains inconclusive. Our aim was to assess cross-sectional associations of food group intakes with circulating IGF-I concentrations in the UK Biobank.MethodsAt recruitment, the UK Biobank participants reported their intake of commonly consumed foods. From these questions, intakes of total vegetables, fresh fruit, red meat, processed meat, poultry, oily fish, non-oily fish, and cheese were estimated. Serum IGF-I concentrations were measured in blood samples collected at recruitment. After exclusions, a total of 438,453 participants were included in this study. Multivariable linear regression was used to assess the associations of food group intakes with circulating IGF-I concentrations.ResultsCompared to never consumers, participants who reported consuming oily fish or non-oily fish ≥ 2 times/week had 1.25 nmol/L (95% confidence interval:1.19–1.31) and 1.16 nmol/L (1.08–1.24) higher IGF-I concentrations, respectively. Participants who reported consuming poultry ≥ 2 times/week had 0.87 nmol/L (0.80–0.94) higher IGF-I concentrations than those who reported never consuming poultry. There were no strong associations between other food groups and IGF-I concentrations.ConclusionsWe found positive associations between oily and non-oily fish intake and circulating IGF-I concentrations. A weaker positive association of IGF-I with poultry intake was also observed. Further research is needed to understand the mechanisms which might explain these associations.

Relationship of serum adiponectin and IGF-I concentrations with progesterone and their effect on pregnancy rates in cows

The aims of this study were to determine serum adiponectin and insulin-like growth factor-I (IGF-I) concentrations in early and late luteal phases following artificial insemination, to evaluate their relationship with progesterone concentrations, and to detect their effects on the pregnancy rate. We used 45 Holstein cows aged 3–4 years who had given birth at least once and who did not have any problem in the genital system as observed on rectal palpation/ultrasonography examination. Presynch–ovsynch synchronization protocol was applied on cows. Blood samples were collected to determine the concentrations of progesterone, adiponectin, and IGF-I on days 5 and 18 following artificial insemination. Pregnancy examination using real-time ultrasonography was performed on day 30 following artificial insemination. Fifteen (33.33%) of the 45 cows were determined as pregnant. The pregnancy rates were increased with increasing progesterone concentration on day 5 following artificial insemination, and the pregnancy rates were the highest (53.84%) among the cows with progesterone concentration of &gt;2.00 ng/mL. Adiponectin and IGF-I concentrations were determined as 26.69±11.84 vs 24.14±9.19 and 17.52±4.19 vs 17.42±2.92, on days 5 and 18 after artificial insemination, respectively (P&gt;0.05). Negative correlation was observed between adiponectin and progesterone concentrations (P&lt;0.05), whereas positive correlation was observed between IGF-I and progesterone on day 5 following artificial insemination (P&lt;0.05). Progesterone and IGF-I concentrations in pregnant cows were higher than in nonpregnant cows on days 5 and 18 following artificial insemination (P&lt;0.05). In conclusion, the progesterone and IGF-I concentrations in early and late luteal phase following artificial insemination had a positive effect on the pregnancy rate. However, although early adiponectin concentration affected progesterone concentrations, it did not affect the pregnancy rate.

Studies of IGF-I and Klotho Protein in Relation to Anabolic-Androgenic Steroid and Growth Hormone Administrations.

It has been suggested to longitudinally monitor Insulin-like growth factor I (IGF-I) as a biomarker for the detection of recombinant growth hormone (GH). Subsequently, it is of interest to understand any confounders of endogenous IGF-I. Herein we have studied if serum IGF-I concentration is affected by the intake of anabolic androgenic steroids (AAS) and the potential connection between IGF-I and klotho protein. Moreover, the usefulness of klotho as a biomarker for recombinant GH intake was assessed in healthy male volunteers. An ongoing administration of AAS did not affect the levels of IGF-I. Klotho protein was ~30% higher in men with an ongoing AAS use compared to those with previous (>2 months ago) AAS use, and the serum klotho protein correlated negatively with luteinizing hormone (LH) (rs = −0.38, p = 0.04) and follicle stimulating hormone (FSH) (rs = −0.35, p = 0.05) levels. Serum IGF-I and klotho concentrations showed no correlation in the AAS using population but showed a strong negative correlation in healthy volunteers (rs = −0.86, p = 0.006). The intake of recombinant GH did not affect the serum concentrations of the klotho levels. In conclusion, IGF-I was not affected by supra-physiological AAS doses in men. Interestingly, an association between AAS intake and serum klotho was seen. The usefulness of klotho as an androgen biomarker warrants further studies, whereas klotho can be discarded as a promising biomarker for GH doping.

Circulating insulin-like growth factor-I and risk of 25 common conditions: outcome-wide analyses in the UK Biobank study

While there is strong epidemiological evidence that circulating insulin-like growth factor-I (IGF-I) is associated with a higher risk of several cancers, little is known about its association with non-cancer outcomes. We investigated associations of circulating IGF-I with risk of 25 common conditions, other than cancer, in a large British cohort. Study participants were 318,749 middle-aged adults enrolled in the UK Biobank Study. Serum IGF-I concentration was measured in samples collected at baseline (2006–2010), and re-measured in 12,334 participants after an average of 4.3 years. We followed-up participants over an average of 11.5 years by linking to hospital admissions and mortality registries. Multivariable-adjusted Cox regressions estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between circulating IGF-I and 25 common conditions, using the repeated IGF-I measurements to correct for regression dilution bias. After correction for multiple testing (P < 0.002), IGF-I was positively associated with carpal tunnel syndrome (HR per 5 nmol/l higher concentration = 1.12, 95% CI 1.08–1.16), and inversely associated with varicose veins (0.90, 0.85–0.95), cataracts (0.97, 0.95–0.99), diabetes (0.92, 0.90–0.95), and iron deficiency anaemia (0.90, 0.86–0.93). The associations for cataracts and diabetes attenuated when restricted to cases diagnosed after five or more years of follow-up, suggesting that these associations were likely affected by reverse causality. Higher IGF-I concentration might be associated with the risk for several conditions, but genetic studies are needed to clarify which associations may be causal.

Associations of circulating insulin-like growth factor-I with intake of dietary proteins and other macronutrients

SummaryBackground & aimsCirculating insulin-like growth factor-I (IGF-I) is associated with the risk of several cancers. Dietary protein intake, particularly dairy protein, may increase circulating IGF-I; however, associations with different protein sources, other macronutrients, and fibre are inconclusive. To investigate the associations between intake of protein, macronutrients and their sources, fibre, and alcohol with serum IGF-I concentrations.MethodsA total of 11,815 participants from UK Biobank who completed ≥4 24-h dietary assessments and had serum IGF-I concentrations measured at baseline were included. Multivariable linear regression was used to assess the cross–sectional associations of macronutrient and fibre intake with circulating IGF-I concentrations.ResultsCirculating IGF-I concentrations were positively associated with intake of total protein (per 2.5% higher energy intake: 0.56 nmol/L (95% confidence interval: 0.47, 0.66)), milk protein: 1.20 nmol/L (0.90, 1.51), and yogurt protein: 1.33 nmol/L (0.79, 1.86), but not with cheese protein: −0.07 nmol/L (−0.40, 0.25). IGF-I concentrations were also positively associated with intake of fibre (per 5 g/day higher intake: 0.46 nmol/L (0.35, 0.57)) and starch from wholegrains (Q5 vs. Q1: 1.08 nmol/L (0.77, 1.39)), and inversely associated with alcohol consumption (>40 g/day vs <1 g/day: −1.36 nmol/L (−1.00, −1.71)).ConclusionsThese results show differing associations with IGF-I concentrations depending on the source of dairy protein, with positive associations with milk and yogurt protein intake but no association with cheese protein. The positive association of fibre and starch from wholegrains with IGF-I warrants further investigation.

Patients with low IGF-I after curative surgery for Cushing's syndrome have an adverse long-term outcome of hypercortisolism-induced myopathy.

Glucocorticoid excess leads to muscle atrophy and weakness in patients with endogenous Cushing's syndrome. Insulin-like growth factor I (IGF-I) is known to have protective effects on muscle loss. We hypothesized that individual serum IGF-I concentrations might be predictive for long-term myopathy outcome in Cushing's syndrome. In a prospective longitudinal study of 31 patients with florid Cushing's syndrome, we analyzed IGF-I and IGF binding protein 3 (IGFBP 3) concentrations at the time of diagnosis and following surgical remission over a period of up to 3 years. We assessed muscle strength by grip strength measurements using a hand grip dynamometer and muscle mass by bio-impedance measurements. Individual serum IGF-I concentrations in the postoperative phase were strongly predictive of long-term grip strength outcome (rs = 0.696, P ≤ 0.001). Also, lower IGF-I concentrations were associated with a lower muscle mass after 3 years (rs = 0.404, P = 0.033). While patients with high IGF-I s.d. scores (SDS; >1.4) showed an improvement in grip strength within the follow-up period (P = 0.009), patients with lower IGF-I SDS (≤-0.4) had a worse outcome with persisting muscle dysfunction. In contrast, preoperative IGF-I concentrations during the florid phase of Cushing's syndrome did not predict long-term muscle function outcome (rs = 0.285, P = 0.127). Lower individual IGF-I concentrations 6 months after curative surgery for Cushing's syndrome are associated with adverse long-term myopathy outcome and IGF-I might be essential for muscle regeneration in the early phase after correction of hypercortisolism.

Changes of Body Condition Scores, Serum Biochemistry and Liver Triacylglycerol in Periparturient Holstein Friesian Dairy Cows Raised in a Small-Holder Farm

This Negative energy balance (NEB) inevitably occurs in periparturient dairy cows. Its consequences are related to reduced cows’ performances. Most studies concerning the NEB are performed in dairy cows of large-scale farms, particularly raised under non-tropical climate. The current study aimed to investigate the changes in body condition score, serum biochemical parameters, and liver triacylglycerol (TAG) accumulation in periparturient Holstein Friesian dairy cows raised by a small-holder farm. In this regard, 10 healthy pregnant dairy cows in a small-holder farm were recruited for the study. At 4 weeks before and 1, 2, 4, and 8 weeks after calving, blood samples were collected for determination of glucose, non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHBA), and insulin-like growth factor-I (IGF-I) concentrations. BCS was evaluated at 4 weeks before and 2 weeks after calving. Liver samples were collected 4 weeks before and 2 weeks after calving to determine TAG concentration. Results revealed that serum NEFA and liver TAG concentration were elevated postpartum. Serum BHBA concentrations increased postpartum and the concentration indicated that dairy cows entered NEB condition as type I ketosis with a longer period. Serum IGF-I concentrations and BCS did not differ between before and after calving. In conclusion, dairy cows raised under small-holder tropical conditions suffered from serious NEB, though the cows had low milk production, as compared with the commercial non-tropical condition.

Leptin Modulates the Response of Brown Adipose Tissue to Negative Energy Balance: Implication of the GH/IGF-I Axis.

The growth hormone (GH)/insulin-like growth factor I (IGF-I) axis is involved in metabolic control. Malnutrition reduces IGF-I and modifies the thermogenic capacity of brown adipose tissue (BAT). Leptin has effects on the GH/IGF-I axis and the function of BAT, but its interaction with IGF-I and the mechanisms involved in the regulation of thermogenesis remains unknown. We studied the GH/IGF-I axis and activation of IGF-I-related signaling and metabolism related to BAT thermogenesis in chronic central leptin infused (L), pair-fed (PF), and control rats. Hypothalamic somatostatin mRNA levels were increased in PF and decreased in L, while pituitary GH mRNA was reduced in PF. Serum GH and IGF-I concentrations were decreased only in PF. In BAT, the association between suppressor of cytokine signaling 3 and the IGF-I receptor was reduced, and phosphorylation of the IGF-I receptor increased in the L group. Phosphorylation of Akt and cyclic AMP response element binding protein and glucose transporter 4 mRNA levels were increased in L and mRNA levels of uncoupling protein-1 (UCP-1) and enzymes involved in lipid anabolism reduced in PF. These results suggest that modifications in UCP-1 in BAT and changes in the GH/IGF-I axis induced by negative energy balance are dependent upon leptin levels.

Circulating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank.

Circulating insulin-like growth factor I (IGF-I) is positively associated with the risks of colorectal, breast, and prostate cancer, but evidence for other less common cancers is limited. In this study, we investigated associations between serum IGF-I concentrations and incidence of less common cancers in the UK Biobank study. To enable comparison of effect estimates, and as positive controls, both common and less common cancer sites (total 30) were included in an outcome-wide analysis. Data from 394,388 cancer-free participants in the UK Biobank study were analyzed. Multivariable adjusted Cox proportional hazards models were used to determine associations between baseline serum IGF-I concentrations and cancer incidence, using repeated IGF-I measurements from up to 14,149 participants to correct for regression dilution bias. Higher IGF-I concentration was associated with increased risks of thyroid cancer [HR per 5 nmol/L higher concentration 1.18; 95% confidence interval (CI), 1.01-1.37] in addition to colorectal (HR, 1.08; 95% CI, 1.03-1.13), breast (HR, 1.11; 95% CI, 1.07-1.15), and prostate cancer (HR, 1.08; 95% CI, 1.05-1.12), and reduced risks of ovarian and liver cancer. Mean follow-up was 6.9 years and the possibility that the observed associations may be influenced by reverse causality bias cannot be excluded. Additional nominally significant associations with malignant melanoma, multiple myeloma, oral cancer, and esophageal squamous cell carcinoma did not survive correction for multiple testing. Studies with longer follow-up and pooled analyses are needed to further assess how broad the role of IGF-I is in cancer development. SIGNIFICANCE: The results from this outcome-wide analysis are consistent with a positive association of IGF-I with cancers at several sites.

Effects of increasing doses of trenbolone acetate and estradiol on finishing phase growth performance, carcass trait responses, and serum metabolites in beef steers following implantation.

Yearling Simmental × Angus crossbred beef steers (n = 240; allotment BW = 365 ± 22.5 kg) from a South Dakota auction facility were transported 117 km to Brookings, SD and used in a randomized complete block design feedlot study to evaluate the effects of implants (both from Zoetis, Parsippany, NJ) containing increasing doses of trenbolone acetate (TBA) and estradiol benzoate (EB) administered 124 d prior to harvest have on finishing phase growth performance, carcass characteristics, and serum concentrations of urea-N (SUN) and insulin-like growth factor I (IGF-I). Thirty pens (10 pens/treatment) were assigned to 1 of 3 treatments: 1) negative control given no implant (NI); 2) a steroidal implant containing 100 mg TBA and 14 mg EB administered subcutaneously in the center one-third of the ear on day 1 (Synovex Choice, Zoetis, Parsippany, NJ; CH); 3) a steroidal implant containing 200 mg TBA and 28 mg EB administered subcutaneously in the center one-third of the ear on day 1 (Synovex Plus, Zoetis; PL). Cattle were fed for 124 d post-implantation. Steers were fed a common diet throughout the study. Treatment effects were evaluated by the use of orthogonal polynomials. Pen was the experimental unit for all analyses; an α of 0.05 determined significance. There was a quadratic effect (P = 0.01) on carcass-adjusted final BW. Increasing doses of TBA and EB resulted in a linear increase for both average daily gain (P = 0.01) and dry matter intake (P = 0.02). A quadratic effect on gain-to-feed ratio was observed (P = 0.01). No quadratic (P ≥ 0.40) or linear (P ≥ 0.14) effects were observed for dressing percentage, rib fat (RF), calculated yield grade, or marbling scores. A quadratic increase (P = 0.01) in hot carcass weight (HCW) and a linear increase (P = 0.01) in ribeye area (REA) were detected. No significant implant × day interaction (P ≥ 0.09) was noted for serum concentrations of urea-N or IGF-I. Implants decreased (P = 0.01) SUN compared with NI. Serum concentration of IGF-I was increased (P = 0.04) in implanted steers compared with NI steers. In yearling crossbred beef steers, the use of steroidal implants containing a combination of 100 mg TBA + 14 mg EB or 200 mg TBA + 28 mg EB increases growth performance, HCW, and REA at equal RF accumulation without detriment to marbling score compared with nonimplanted steers.

Associations between Maternal and Fetal Levels of Total Adiponectin, High Molecular Weight Adiponectin, Selected Somatomedins, and Birth Weight of Infants of Smoking and Non-Smoking Mothers.

The aim of the study was to determine the relationships between maternal smoking, total adiponectin, high molecular weight adiponectin (HMW adiponectin), selected somatomedins, and the birth weight of newborns. A total of 78 women with a healthy, singleton pregnancy, 41 active smokers and 37 non-smokers, and their offspring were studied. Total and HMW adiponectin, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) and 2 (IGFBP-2) were determined in maternal and cord blood by enzyme-link immunosorbent assay. Serum levels of total and HMW adiponectin were lower in smokers compared to the tobacco abstinent in both the mothers (p = 0.013; p = 0.006) and the infants (p = 0.001; p = 0.047). In smoking women and their children, serum concentrations of IGF-I were significantly lower (p = 0.014; p = 0.042), IGFBP-1 significantly higher (p = 0.009; p = 0.039), and IGFBP-2 did not differ from that observed in the non-smoking group. In multivariate analysis performed on the whole group of mothers, the highest impact of serum cotinine and IGFBP-2 levels were indicated for adiponectin and cotinine and the number of cigarettes/day for HMW adiponectin concentration. In correlation analysis estimated separately for smokers and non-smokers, neonatal birth weight was positively associated with total and HMW adiponectin concentrations in umbilical cord blood. Birth weight was also inversely associated with IGFBP-1 and positively correlated with IGF-I levels in maternal serum as well as in cord blood (r = −0.317, p = 0.005; r = −0.294, p = 0.004; r = 0.245, p = 0.031; r = 0.271, p = 0.009, respectively). The present study showed the levels of total and HMW adiponectin in umbilical cord blood may have a significant effect on fetal development. Both IGF-I and IGFBP-1 concentrations also play an essential role in fetal growth, which is an important predictor of birth weight. Cigarette smoking during pregnancy negatively affected adiponectin and the insulin growth factor profile in the serum of women and the cord blood and may be the reason for the lower birth weight of the smokers newborns compared with the nonsmokers offspring.

A Proposal for the Interpretation of Serum IGF-I Concentration as Part of Laboratory Screening in Children with Growth Failure

The serum insulin-like growth factor-I (IGF-I) concentration is commonly used as a screening tool for growth hormone deficiency (GHD), but there is no consensus on the cut-off limit of IGF-I standard deviation score (SDS) to perform GH stimulation tests for confirmation or exclusion of GHD. We argue that the cut-off limit is dependent on the clinical pre-test likelihood of GHD and propose a diagnostic strategy in which the cut-off limit varies between zero to -2 SDS.

Insulin-like growth factor I (IGF-I) and its present significance in digestive system diseases

Insulin-like growth factor I (IGF-I) is a main mediator of growth hormone’s (GH) action. Under physiological conditions, IGF-I is responsible for growth and development of organism through influence on proliferation and differentiation of cells. IGF-I is produced in almost all tissues of organism and its activity is determined by interaction with specific receptors (IGF-IR, IGF-IIR) and IGF-binding proteins (IGFBP-1 - IGFBP-6), and by proteases hydrolyzing IGFBPs as well. Currently, a surge of interest on insulin-like growth factor I as a potential factor contributing to the development of neoplasms, including neoplasms of digestive system, is observed. IGFBPs and IGF-IR may also be of importance in etiology and pathogenesis of cancer. It is assumed that high serum concentration of IGF-I may increase the risk of cancer development whereas high serum concentration of IGFBP-3 may inhibit the progression of the disease. Until recently, attempts of modulating the concentration of IGF-I with the use of pharmacological agents of diverse mechanisms of action under innovative anti-cancer therapies, have been made. Lately, it is pointed to the possibility of application of IGF-I in the management of certain diseases of digestive system. It was observed that IGF-I not only contributes to the maintenance of normal structure and function of epithelium in the gastrointestinal tract but also stimulates repair processes in damaged mucosa. Results of preliminary studies on the treatment of short bowel syndrome, gastric ulcer disease, enteritis induced by chemo- and radiotherapy, and inflammatory bowel disease with the use of exogenous IGF-I are encouraging.

Association of polymorphisms in the IGF-I, GHR and STAT5A genes with serum IGF-I concentration and reproductive performance of Holstein dairy cows

This study was conducted to evaluate associations of polymorphisms in the genes for the growth hormone receptor (GHR), insulin-like growth factor I (IGF-I) and signal transducer and activator of transcription 5A (STAT5A) with serum concentrations of IGF-I, reproductive performance and milk production of postpartum Holstein dairy cows. Days from calving to first ovulation (DTO) and calving to conception interval (CCI) were evaluated in 95 Holstein cows. Serum concentrations of IGF-I and β-hydroxybutyrate (BHBA) were quantified in samples collected in sequential blood collections. Genotyping of the IGF-I and STAT5A genes was performed. The IGF-I polymorphism distribution was 35.9% CC, 46.1% CT and 18% TT. The IGF-I concentrations in circulation were greater in cows of the TT compared with both the CT and CC groups (P < 0.05). Genotype had a linear association (P < 0.05) with DTO and CCI, which were less for cows of the TT group. There was no association of STAT5A BstEII on serum IGF-I or reproductive variables (P> 0.05). When combining the GHR AluI T allele, obtained in a previous study, and the IGF-I SnaBI T allele from the current study, for the same cows, there were additive associations of both with serum IGF-I, BHBA, number of services per conception, DTO and CCI (P < 0.05). Thus, the IGF-1 SnaBI TT appears to be associated with fewer DTO and lesser CCI of lactating dairy cows and had an additive association with the GHR AluI T allele on indicators for improvement of fertility.