Adolescents with clinical type 1 diabetes display reduced red blood cell glucose transporter isoform 1 (GLUT1).

Type 1 diabetic (T1D) adolescent children on insulin therapy suffer episodes of both hyper- and hypoglycemic episodes. Glucose transporter isoform GLUT1 expressed in blood-brain barrier (BBB) and red blood cells (RBC) compensates for perturbed circulating glucose toward protecting the supply to brain and RBCs. We hypothesized that RBC-GLUT1 concentration, as a surrogate for BBB-GLUT1, is altered in T1D children. To test this hypothesis, we measured RBC-GLUT1 by enzyme-linked immunosorbent assay (ELISA) in T1D children (n = 72; mean age 15.3 ± 0.2 yr) and control children (CON; n = 11; mean age 15.6 ± 0.9 yr) after 12 h of euglycemia and during a hyperinsulinemic-hypoglycemic clamp with a nadir blood glucose of ~3.3 mmol/L for 90 min (clamp I) or ~3 mmol/L for 45 min (clamp II). Reduced baseline RBC-GLUT1 was observed in T1D (2.4 ± 0.17 ng/ng membrane protein); vs. CON (4.2 ± 0.61 ng/ng protein) (p < 0.0001). Additionally, baseline RBC-GLUT1 in T1D negatively correlated with hemoglobin A1c (HbA1c) (R = -0.23, p < 0.05) but not in CON (R = 0.06, p < 0.9). Acute decline in serum glucose to 3.3 mmol/L (90 min) or 3 mmol/L (45 min) did not change baseline RBC-GLUT1 in T1D or CON children. We conclude that reduced RBC-GLUT1 encountered in T1D, with no ability to compensate by increasing during acute hypoglycemia over the durations examined, may demonstrate a vulnerability of impaired RBC glucose transport (serving as a surrogate for BBB), especially in those with the worst control. We speculate that this may contribute to the perturbed cognition seen in T1D adolescents.

Myocardial macronutrient transporter adaptations in the adult pregestational female intrauterine and postnatal growth-restricted offspring.

Associations between exponential childhood growth superimposed on low birth weight and adult onset cardiovascular disease with glucose intolerance/type 2 diabetes mellitus exist in epidemiological investigations. To determine the metabolic adaptations that guard against myocardial failure on subsequent exposure to hypoxia, we compared with controls (CON), the effect of intrauterine (IUGR), postnatal (PNGR), and intrauterine and postnatal (IPGR) calorie and growth restriction (n = 6/group) on myocardial macronutrient transporter (fatty acid and glucose) -mediated uptake in pregestational young female adult rat offspring. A higher myocardial FAT/CD36 protein expression in IUGR, PNGR, and IPGR, with higher FATP1 in IUGR, FATP6 in PNGR, FABP-c in PNGR and IPGR, and no change in GLUT4 of all groups was observed. These adaptive macronutrient transporter protein changes were associated with no change in myocardial [(3)H]bromopalmitate accumulation but a diminution in 2-deoxy-[(14)C]glucose uptake. Examination of the sarcolemmal subfraction revealed higher basal concentrations of FAT/CD36 in PNGR and FATP1 and GLUT4 in IUGR, PNGR, and IPGR vs. CON. Exogenous insulin uniformly further enhanced sarcolemmal association of these macronutrient transporter proteins above that of basal, with the exception of insulin resistance of FATP1 and GLUT4 in IUGR and FAT/CD36 in PNGR. The basal sarcolemmal macronutrient transporter adaptations proved protective against subsequent chronic hypoxic exposure (7 days) only in IUGR and PNGR, with notable deterioration in IPGR and CON of the echocardiographic ejection fraction. We conclude that the IUGR and PNGR pregestational adult female offspring displayed a resistance to insulin-induced translocation of FATP1, GLUT4, or FAT/CD36 to the myocardial sarcolemma due to preexistent higher basal concentrations. This basal adaptation of myocardial macronutrient transporters ensured adequate fatty acid uptake, thereby proving protective against chronic hypoxia-induced myocardial compromise.

Pre- and postnatal calorie restriction perturbs early hypothalamic neuropeptide and energy balance.

Energy balance is regulated by circulating leptin concentrations and hypothalamic leptin receptor (ObRb) signaling via STAT3 but is inhibited by SOCS3 and PTP1B. Leptin signaling enhances anorexigenic neuropeptides and receptor (POMC, MC3-R, MC4-R) activation while suppressing orexigenic neuropeptides (NPY, AgRP). We investigated in a sex-specific manner the early (PN2) and late (PN21) postnatal hypothalamic mechanisms in response to intrauterine (IUGR), postnatal (PNGR), and combined (IPGR) calorie and growth restriction. At PN2, both male and female IUGR were hypoleptinemic, but hypothalamic leptin signaling in females was activated as seen by enhanced STAT3. In addition, increased SOCS3 and PTP1B supported early initiation of leptin resistance in females that led to elevated AgRP but diminished MC3-R and MC4-R. In contrast, males demonstrated leptin sensitivity seen as a reduction in PTP1B and MC3-R and MC4-R with no effect on neuropeptide expression. At PN21, with adequate postnatal caloric intake, a sex-specific dichotomy in leptin concentrations was seen in IUGR, with euleptinemia in males indicative of persisting leptin sensitivity and hyperleptinemia in females consistent with leptin resistance, both with normal hypothalamic ObRb signaling, neuropeptides, and energy balance. In contrast, superimposition of PNGR upon IUGR (IPGR) led to diminished leptin concentrations with enhanced PTP1B and an imbalance in arcuate nuclear NPY/AgRP and POMC expression that favored exponential hyperphagia and diminished energy expenditure postweaning. We conclude that IUGR results in sex-specific leptin resistance observed mainly in females, whereas PNGR and IPGR abolish this sex-specificity, setting the stage for acquiring obesity after weaning.

Early exposure of the pregestational intrauterine and postnatal growth-restricted female offspring to a peroxisome proliferator-activated receptor-{gamma} agonist.

Prenatal nutrient restriction with intrauterine growth restriction (IUGR) alters basal and glucose-stimulated insulin response and hepatic metabolic adaptation. The effect of early intervention with insulin-sensitizing peroxisome proliferator-activated receptor gamma agonists was examined in the metabolically maladapted F(1) pregestational IUGR offspring with a propensity toward pregnancy-induced gestational diabetes. The effect of rosiglitazone maleate [RG; 11 micromol/day from postnatal day (PN) 21 to PN60] vs. placebo (PL) on metabolic adaptations in 2-mo-old F(1) female rats subjected to prenatal (IUGR), postnatal (PNGR), or pre- and postnatal (IUGR + PNGR) nutrient restriction was investigated compared with control (CON). RG vs. PL had no effect on body weight or plasma glucose concentrations but increased subcutaneous white and brown adipose tissue and plasma cholesterol concentrations in all three experimental groups. Glucose tolerance tests with a 1:1 mixture of [2-(2)H(2)]- and [6,6-(2)H(2)]glucose in RG IUGR vs. PL IUGR revealed glucose tolerance with a lower glucose-stimulated insulin release (GSIR) and suppressed endogenous hepatic glucose production (HGP) with no difference in glucose clearance (GC) and recycling (GR). RG PNGR, although similar to PL CON, was hyperglycemic vs. PL PNGR with reduced GR but no difference in the existent low GSIR, HGP, and GC. RG IUGR + PNGR overall was no different from the PL counterpart. Insulin tolerance tests revealed perturbed recovery to baseline from the exaggerated hypoglycemia in RG vs. the PL groups with the only exception being RG PNGR where further worsening of hypoglycemia over PL PNGR was minimal with full recovery to baseline. These observations support that early intervention with RG suppressed HGP in IUGR vs. PL IUGR, without increasing GSIR similar to that seen in CON. Although RG reversed PNGR to the PL CON metabolic state, no such insulin-sensitizing effect was realized in IUGR + PNGR.

Peroxisome proliferator-activated receptor-gamma agonist improves skeletal muscle insulin signaling in the pregestational intrauterine growth-restricted rat offspring.

The effect of early intervention with a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist on skeletal muscle GLUT4 translocation and insulin signaling was examined in intrauterine (IUGR) and postnatal (PNGR) growth-restricted pregestational female rat offspring. Rosiglitazone [11 mumol/day provided from postnatal day (PN)21 to PN60] improved skeletal muscle insulin sensitivity and GLUT4 translocation in prenatal nutrient restriction [50% calories from embryonic day (e)11 to e21; IUGR] with (IUGR+PNGR) and without (IUGR) postnatal nutrient restriction (50% calories from PN1 to PN21; PNGR) similar to that of control (ad libitum feeds throughout; Con) (n = 6 each). This was accomplished by diminished basal and improved insulin-responsive GLUT4 association with the plasma membrane in IUGR, IUGR+PNGR, and PNGR mimicking that in Con (P < 0.005). While no change in p85-phosphatidylinositol 3-kinase (PI3-K) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was observed, a decrease in protein tyrosine phosphatase 1B (PTP1B; P < 0.0002) and SH2-containing protein tyrosine phosphatase 2 (SHP2; P < 0.05) contributing to the rosiglitazone-induced insulin sensitivity was seen only in IUGR+PNGR. In contrast, an increase in phosphorylated 5'-adenosine monophosphate kinase (pAMPK; P < 0.04) and insulin responsiveness of phosphorylated phosphoinositide-dependent protein kinase-1 (pPDK1; P < 0.05), pAkt (P < 0.01), and particularly pPKCzeta (P < 0.0001) and its corresponding enzyme activity (P < 0.005) were observed in all four experimental groups. We conclude that early introduction of PPARgamma agonist improved skeletal muscle activation of AMPK and insulin signaling, resulting in insulin-independent AMPK and insulin-responsive GLUT4 association with plasma membranes in IUGR, IUGR+PNGR, and PNGR adult offspring, similar to that of Con. These findings support a role for insulin sensitizers in preventing the subsequent development of gestational or type 2 diabetes mellitus in intrauterine and postnatal growth-restricted offspring.

Embryo-transfer of the F2 postnatal calorie restricted female rat offspring into a control intra-uterine environment normalizes the metabolic phenotype.

OBJECTIVE: Postnatal calorie and growth restriction (PNGR) in the first generation (F1) rat female offspring causes a lean and glucose tolerant phenotype associated with hypoinsulinemia and reduced glucose-stimulated insulin secretion (GSIS). Despite the absence of gestational hyperglycemia in the F1 PNGR female, naturally born second generation (F2) PNGR female adult offspring reportedly exhibit obesity, hyperglycemia with insulin resistance. The objective of this study was to determine the role of the intrauterine environment on the heritability of the trans-generational phenotypic expression in the F2 PNGR female adult offspring. MATERIALS/METHODS: We performed embryo transfer (ET) of the F2 embryos from the procreating F1 pregnant PNGR or control (CON) females to gestate in control recipient rat mothers. Employing stable isotopes glucose metabolic kinetics was determined. RESULTS: Birth weight, postnatal growth pattern and white adipose tissue in female F2 ET-PNGR were similar to ET-CON. Similarly, no differences in basal glucose and insulin concentrations, GSIS, glucose futile cycling and glucose clearance were seen. When compared to F2 ET-CON, F2 ET-PNGR showed no overall difference in glucose or hepatic glucose production (HGP) AUCs with minimal hyperglycemia (p<0.04) as a result of unsuppressed endogenous HGP (p<0.02) observed only during the first phase of IVGTT. CONCLUSIONS: We conclude that the lean, glucose tolerant and hypoinsulinemic phenotype with reduced GSIS in the F1 generation is nearly normalized when the embryo-transferred F2 offspring gestates in a normal metabolic environment. This observation supports a role for the intra-uterine environment in modifying the heritability of the trans-generational PNGR phenotype.

Glucose intolerance and lipid metabolic adaptations in response to intrauterine and postnatal calorie restriction in male adult rats.

Enhanced de novo lipogenesis (DNL), an adult hepatic adaption, is seen with high carbohydrate or low-fat diets. We hypothesized that ad libitum intake after prenatal calorie restriction will result in adult-onset glucose intolerance and enhanced DNL with modified lipid metabolic gene expression profile. Stable isotopes were used in 15-month-old adult male rat offspring exposed to prenatal (IUGR), pre- and postnatal (IPGR), or postnatal (PNGR) caloric restriction vs. controls (CON). IUGR vs. CON were heavier with hepatomegaly but unchanged visceral white adipose tissue (WAT), glucose intolerant with reduced glucose-stimulated insulin secretion (GSIS), pancreatic ß-cell mass, and total glucose clearance rate but unsuppressed hepatic glucose production. Liver glucose transporter (Glut) 1 and DNL increased with decreased hepatic acetyl-CoA carboxylase (ACC) and fatty acid synthase but increased WAT fatty acid transport protein-1 and peroxisomal proliferator-activated receptor-γ, resistin, and visfatin gene expression. In contrast, PNGR and IPGR were lighter, had reduced visceral WAT, and were glucose tolerant with unchanged hepatic glucose production but with increased GSIS, ß-cell mass, glucose clearance rate, and WAT insulin receptor. Hepatic Glut1 and DNL were also increased in lean IPGR and PNGR with increased hepatic ACC, phosphorylated ACC, and pAMPK and reduced WAT fatty acid transport protein-1, peroxisomal proliferator-activated receptor-γ, and ACCα. We conclude the following: 1) the heavy, glucose-intolerant and insulin-resistant IUGR adult phenotype is ameliorated by postnatal caloric restriction; 2) increased DNL paralleling hepatic Glut1 is a biomarker of exposure to early caloric restriction rather than the adult metabolic status; 3) hepatic lipid enzyme expression reflects GSIS rather than DNL; and 4) WAT gene expression reflects an obesogenic vs. lean phenotype.

Early postnatal caloric restriction protects adult male intrauterine growth-restricted offspring from obesity.

Postnatal ad libitum caloric intake superimposed on intrauterine growth restriction (IUGR) is associated with adult-onset obesity, insulin resistance, and type 2 diabetes mellitus (T2DM). We hypothesized that this paradigm of prenatal nutrient deprivation-induced programming can be reversed with the introduction of early postnatal calorie restriction. Ten-month-old male rats exposed to either prenatal nutrient restriction with ad libitum postnatal intake (IUGR), pre- and postnatal nutrient restriction (IPGR), or postnatal nutrient restriction limited to the suckling phase (50% from postnatal [PN]1 to PN21) (PNGR) were compared with age-matched controls (CON). Visceral adiposity, metabolic profile, and insulin sensitivity by hyperinsulinemic-euglycemic clamps were examined. The 10-month-old male IUGR group had a 1.5- to 2.0-fold increase in subcutaneous and visceral fat (P < 0.0002) while remaining euglycemic, insulin sensitive, inactive, and exhibiting metabolic inflexibility (Vo(2)) versus CON. The IPGR group remained lean, euglycemic, insulin sensitive, and active while maintaining metabolic flexibility. The PNGR group was insulin sensitive, similar to IPGR, but less active while maintaining metabolic flexibility. We conclude that IUGR resulted in obesity without insulin resistance and energy metabolic perturbations prior to development of glucose intolerance and T2DM. Postnatal nutrient restriction superimposed on IUGR was protective, restoring metabolic normalcy to a lean and active phenotype.

Early exercise regimen improves insulin sensitivity in the intrauterine growth-restricted adult female rat offspring.

We examined the effect of early exercise training (Ex) on glucose kinetics, basal, and insulin-stimulated skeletal muscle (SKM) plasma membrane (PM) GLUT4 in pre- and/or postnatal nutrient-restricted adult rat offspring compared with sedentary (Sed) state. Pregestational control female (Ex CON vs. Sed CON) and offspring exposed to prenatal (Ex IUGR vs. Sed IUGR), postnatal (Ex PNGR vs. Sed PNGR), or pre- and postnatal (Ex IUGR + PNGR vs. Sed IUGR + PNGR) nutrient restriction were studied. The combined effect of exercise and pre/postnatal nutrition in the Ex IUGR demonstrated positive effects on basal and glucose-stimulated plasma insulin response (GSIR) with suppression of endogenous hepatic glucose production (HGP) compared with sedentary state. Ex PNGR was hyperglycemic after glucose challenge with no change in glucose-stimulated insulin production or HGP compared with sedentary state. Ex IUGR + PNGR remained glucose tolerant with unchanged glucose-stimulated insulin production but increased endogenous HGP compared with sedentary state. Basal SKM PM-associated GLUT4 was unchanged by exercise in all four groups. Whereas Ex PNGR and Ex IUGR + PNGR insulin responsiveness was similar to that of Ex CON, Ex IUGR remained nonresponsive to insulin. Early introduction of regular Ex in the pregestational female offspring had a positive effect on hepatic adaptation to GSIR and HGP in IUGR and IUGR + PNGR, with no effect in PNGR. Change in insulin responsiveness of SKM GLUT4 translocation was observed in exercised IUGR + PNGR and PNGR but not in exercised IUGR.

Histone code modifications repress glucose transporter 4 expression in the intrauterine growth-restricted offspring.

We examined transcriptional and epigenetic mechanism(s) behind diminished skeletal muscle GLUT4 mRNA in intrauterine growth-restricted (IUGR) female rat offspring. An increase in MEF2D (inhibitor) with a decline in MEF2A (activator) and MyoD (co-activator) binding to the glut4 promoter in IUGR versus control was observed. The functional role of MEF2/MyoD-binding sites and neighboring three CpG clusters in glut4 gene transcription was confirmed in C2C12 muscle cells. No differential methylation of these three and other CpG clusters in the glut4 promoter occurred. DNA methyltransferase 1 (DNMT1) in postnatal, DNMT3a, and DNMT3b in adult was differentially recruited with increased MeCP2 (methyl CpG-binding protein) concentrations to bind the IUGR glut4 gene. Covalent modifications of the histone (H) code consisted of H3.K14 de-acetylation by recruitment of histone deacetylase (HDAC) 1 and enhanced association of HDAC4 enzymes. This set the stage for Suv39H1 methylase-mediated di-methylation of H3.K9 and increased recruitment of heterochromatin protein 1alpha, which partially inactivates postnatal and adult IUGR glut4 gene transcription. Further increased interactions in the adult IUGR between DNMT3a/DNMT3b and HDAC1 and MEF2D and HDAC1/HDAC4 and decreased association between MyoD and MEF2A existed. We conclude that epigenetic mechanisms consisting of histone code modifications repress skeletal muscle glut4 transcription in the postnatal period and persist in the adult female IUGR offspring.

Metabolic programming in the pathogenesis of insulin resistance.

This review focuses on different animal models of nutrient perturbations, inclusive of restrictive and excessive states mimicking human situations during pregnancy and lactation that cause aberrations in the offspring. These aberrations consist of diminished insulin sensitivity in the presence of defective insulin production. These phenotypic changes are due to altered peripheral tissue post-insulin receptor signaling mechanisms and pancreatic beta-islet insulin synthesis and secretion defects. While these changes during in utero or postnatal life serve as essential adaptations to overcome adverse conditions, they become maladaptive subsequently and set the stage for type 2 diabetes mellitus. Pregnancy leads to gestational diabetes with trans-generational propagation of the insulin resistant phenotype. This is in response to the metabolically aberrant maternal in utero environment, and tissue specific epigenetic perturbations that permanently alter expression of critical genes transmitted to future generations. These heritable aberrations consisting of altered DNA methylation and histone modifications remodel chromatin and affect transcription of key genes. Along with an altered in utero environment, these chromatin modifications contribute to the world-wide epidemic of type 2 diabetes mellitus, with nutrient excess dominating in developed and nutrient restriction in developing countries.

Transgenerational inheritance of the insulin-resistant phenotype in embryo-transferred intrauterine growth-restricted adult female rat offspring.

To determine mechanisms underlying the transgenerational presence of metabolic perturbations in the intrauterine growth-restricted second-generation adult females (F2 IUGR) despite normalizing the in utero metabolic environment, we examined in vivo glucose kinetics and in vitro skeletal muscle postinsulin receptor signaling after embryo transfer of first generation (F1 IUGR) to control maternal environment. Female F2 rats, procreated by F1 pre- and postnatally nutrient- and growth-restricted (IUGR) mothers but embryo transferred to gestate in control mothers, were compared with similarly gestating age- and sex-matched control (CON) F2 progeny. Although there were no differences in birth weight or postnatal growth patterns, the F2 IUGR had increased hepatic weight, fasting hyperglycemia, hyperinsulinemia, and unsuppressed hepatic glucose production, with no change in glucose futile cycling or clearance, compared with F2 CON. These hormonal and metabolic aberrations were associated with increased skeletal muscle total GLUT4 and pAkt concentrations but decreased plasma membrane-associated GLUT4, total pPKCzeta, and PKCzeta enzyme activity, with no change in total SHP2 and PTP1B concentrations in IUGR F2 compared with F2 CON. We conclude that transgenerational presence of aberrant glucose/insulin metabolism and skeletal muscle insulin signaling of the adult F2 IUGR female offspring is independent of the immediate intrauterine environment, supporting nutritionally induced heritable mechanisms contributing to the epidemic of type 2 diabetes mellitus.

Glucose metabolic adaptations in the intrauterine growth-restricted adult female rat offspring.

We studied glucose metabolic adaptations in the intrauterine growth-restricted (IUGR) rat offspring to decipher glucose homeostasis in metabolic programming. Glucose futile cycling (GFC), which is altered when there is imbalance between glucose production and utilization, was studied during a glucose tolerance test (GTT) in 2-day-old (n = 8), 2-mo-old (n = 22), and 15-mo-old (n = 22) female rat offspring. The IUGR rats exposed to either prenatal (CM/SP, n = 5 per age), postnatal (SM/CP, n = 6), or pre- and postnatal (SM/SP, n = 6) nutrient restriction were compared with age-matched controls (CM/CP, n = 5). At 2 days, IUGR pups (SP) were smaller and glucose intolerant and had increased hepatic glucose production and increased glucose disposal (P < 0.01) compared with controls (CP). At 2 mo, the GTT, glucose clearance, and GFC did not change. However, a decline in hepatic glucose-6-phosphatase (P < 0.05) and fructose-1,6-biphosphatase (P < 0.05) enzyme activities in the IUGR offspring was detected. At 15 mo, prenatal nutrient restriction (CM/SP) resulted in greater weight gain (P < 0.01) and hyperinsulinemia (P < 0.001) compared with postnatal nutrient restriction (SM/CP). A decline in GFC in the face of a normal GTT occurred in both the prenatal (CM/SP, P < 0.01) and postnatal calorie (SM/CP, P < 0.03) and growth-restricted offspring. The IUGR offspring with pre- and postnatal nutrient restriction (SM/SP) were smaller, hypoinsulinemic (P < 0.03), and hypoleptinemic (P < 0.03), with no change in GTT, hepatic glucose production, GFC, or glucose clearance. We conclude that there is pre- and postnatal programming that affects the postnatal compensatory adaptation of GFC and disposal initiated by changes in circulating insulin concentrations, thereby determining hepatic insulin sensitivity in a phenotype-specific manner.

GLUT4 expression and subcellular localization in the intrauterine growth-restricted adult rat female offspring.

Intrauterine growth restriction (IUGR) leads to obesity, glucose intolerance, and type 2 diabetes mellitus in the adult. To determine the mechanism(s) behind this "metabolic imprinting" phenomenon, we examined the effect of total calorie restriction during mid- to late gestation modified by postnatal ad libitum access to nutrients (CM/SP) or nutrient restriction (SM/SP) vs. postnatal nutrient restriction alone (SM/CP) on skeletal muscle and white adipose tissue (WAT) insulin-responsive glucose transporter isoform (GLUT4) expression and insulin-responsive translocation. A decline in skeletal muscle GLUT4 expression and protein concentrations was noted only in the SM/SP and SM/CP groups. In contrast, WAT demonstrated no change in GLUT4 expression and protein concentrations in all experimental groups. The altered in utero hormonal/metabolic milieu was associated with a compensatory adaptation that persisted in the adult and consisted of an increase in the skeletal muscle basal plasma membrane-associated GLUT4 concentrations. This perturbation led to no further exogenous insulin-induced GLUT4 translocation, thereby disabling the insulin responsiveness of the skeletal muscle but retaining it in WAT. These changes, which present at birth, collectively maximize basal glucose transport to the compromised skeletal muscle with a relative resistance to exogenous/postprandial insulin. Preservation of insulin responsiveness in WAT may serve as a sink that absorbs postprandial nutrients that can no longer efficiently access skeletal muscle. We speculate that, in utero, GLUT4 aberrations may predict type 2 diabetes mellitus, whereas postnatal nutrient intake may predict obesity, thereby explaining the heterogeneous phenotype of the IUGR adult offspring.

Intra-uterine growth restriction downregulates the hepatic toll like receptor-4 expression and function.

Maternal starvation is a significant cause of intrauterine growth restriction (IUGR) in the world and increases the risk of infection in the neonate. We examined the effect of maternal starvation on Toll like receptor (TLR)4 expression in hepatic, splenic and intestinal tissues obtained from the adult IUGR offspring of prenatal calorie restricted rats. The hepatic TLR4 protein concentration was undetectable in the IUGR rats that had restricted milk intake during the suckling period (SM/SP; n = 4. p < 0.05) as compared to the normal growth controls (CM/CP; n = 4), and access to ad lib milk intake during the sucking period partially corrected the hepatic TLR4 expression (SM/CP; n = 4). IUGR had no effect on the splenic (n = 4) or intestinal (n = 4) TLR4 mRNA levels. In the liver, IUGR led to a 20% increase in baseline tumor necrosis factor (TNF)-alpha mRNA expression (p < 0.03) and a 70% increase in interleukin-1beta (IL-1beta) mRNA expression (p < 0.008) as compared to the control rats (CM/CP; n = 7). LPS-induced hepatic TNF-alpha release was significantly higher in SM/SP as compared to CM/CP. We propose that IUGR dysregulates TLR4 expression and function in the offspring, which may help explain the increased risk of Gram-negative sepsis and inflammatory diseases in this population.

Regulation of oligopeptide transporter (Pept-1) in experimental diabetes.

The knowledge of expression and biology of the intestinal oligopeptide transporter (Pept-1) in a metabolic disorder such as diabetes may have nutritional and pharmacological implications. To study this problem, rats were made diabetic by streptozotocin injection, and Western and Northern blot analyses and nuclear run-on assay were used to determine the protein and gene expressions of Pept-1 and its rate of transcription, respectively. Uncontrolled diabetes for 96 h increased the activity of Pept-1 in the brush-border membrane of intestinal mucosa. Studies of Michaelis-Menten constant, maximal velocity, and protein expression of Pept-1 indicated that an increase in the abundance of this transporter was responsible for the increased activity. Studies of the gene expression showed that uncontrolled diabetes increased the abundance of mRNA encoding Pept-1 without altering its rate of transcription. Lastly, studies of the specificity of the above effect showed that uncontrolled diabetes similarly affected the protein and gene expressions of Pept-1 located in the kidney. In conclusion, the data show that 1) uncontrolled diabetes has a tropic effect on Pept-1 and 2) the effect is systemic, and its molecular mechanism appears to be an increase in the stabilization of mRNA encoding Pept-1.