Rosa Galván

Relationship Between Circulating Adipokines and Insulin Resistance During Pregnancy and Postpartum in Women with Gestational Diabetes

BACKGROUND AND AIMS We undertook this study to assess the relationship between circulating adipokines and insulin resistance during pregnancy and postpartum in women with gestational diabetes mellitus (GDM). METHODS This was a prospective study including 60 women with GDM and 60 subjects with normal gestation who were evaluated at gestational week 30, 6 weeks and 6 months postpartum. Circulating adipokines that were evaluated during the study were leptin, adiponectin, retinol-binding protein-4 (RBP4), and tumor necrosis factor-alpha (TNF-α). RESULTS Women with GDM showed higher insulin resistance measured by HOMA-IR than subjects with normal gestation (2.3 ± 2.3 vs. 1.3 ± 0.95). There was no difference between groups in adipokines; however, in women with a healthy pregnancy, RBP4 was associated with insulin resistance (r = 0.47, p <0.05). At 6 weeks and 6 months postpartum, women with previous GDM exhibited persistent elevated leptin and insulin resistance. RBP4 was associated with insulin resistance only in women with a previous healthy pregnancy (r = 0.51, p <0.05). In addition, progressively impaired glucose tolerance was observed after delivery in women with previous GDM. CONCLUSIONS It was demonstrated that GDM is associated with greater insulin resistance than observed in normal pregnancy; however, adipokines are similar in both groups. RBP4 levels are significantly associated with insulin resistance in healthy women during pregnancy and postpartum. After a pregnancy complicated by GDM, leptin and insulin resistance remain elevated and glucose tolerance worsens.

Adiponectin is associated with low bone mineral density in elderly men

OBJECTIVE Recent evidence suggests that adiponectin may play a role in bone metabolism. Previous studies demonstrated that the adiponectin levels had a negative correlation with bone mineral density (BMD) in women. However, little is known about the relationship between adiponectin and BMD in men. The aim of this study was to determinate the relationship between the adiponectin levels and BMD in elderly men. DESIGN Cross-sectional study including 92 healthy men aged 60-80 years. METHODS Main outcome measures were the adiponectin levels estimated by RIA and BMD at lumbar spine and femoral neck using dual energy X-ray absorptiometry. Results The negative correlation between adiponectin and BMD at the spine was r=-0.209, (P<0.05) and at the femoral neck was r=-0.237, (P<0.001). These correlations disappeared after adjustment for body mass index (BMI). When stratified by BMI, the relationship between BMD and adiponectin remained significant in the subgroup of participants with BMI >27 kg/m(2), but disappeared in men with BMI <or=27 kg/m(2). In multiple regression analysis, adiponectin was a significant determinant of BMD at the spine, not at the femoral neck, in those with BMI >27. CONCLUSION BMD is negatively associated with the adiponectin levels in men older than 60 years and this relationship is greater in those men with BMI >27, which suggests a plausible connection between bone and fat tissue.

Effect of testosterone therapy on lumbar spine and hip mineral density in elderly men

Objective. The aim of the present study was to analyse the effect of testosterone therapy on bone mineral density in healthy elderly men who had low levels of total testosterone. Design. Randomized, double-blind, placebo-controlled study. Participants. Forty-eight men over 60 years old with decreased testosterone levels (≤320 ng/dL) comprised the study. Twenty-five out of 48 received intramuscular injections of testosterone enanthate every three weeks during 12 months; the remaining 23 participants formed the control group. All participants had measurements of bone mineral density (BMD) in both lumbar spine and hip before and at the end of the study as well as testosterone and 17-β estradiol levels. Results: Testosterone treated group exhibited a significant (p < 0.05) increment (from 1.198 ± 0.153 to 1.240 ± 0.141 g/cm2) in lumbar BMD in parallel with a significant (p < 0.001) increment (from 301 ± 32 to 471 ± 107 ng/dL) in testosterone concentrations, whereas no significant change occurred in femoral neck BMD. Conclusions. Testosterone therapy elicited a positive effect only in lumbar BMD in elderly men with diminished testosterone serum levels.

Serum leptin and somatotropin components correlate with neonatal birth weight.

Objective: To determine whether cord sera leptin and components of the somatotropin axis – growth hormone (GH), total (t) and free (f) insulin-like growth factor (IGF), IGF-binding protein-3 (IGFBP-3), and insulin – correlate with birth weight. Design: Cross-sectional study of 22 newborns, 12 with normal birth weight (NBW) and 10 with low birth weight (LBW), in a population of healthy mothers with an apparent normal pregnancy. Methods: Paired mother–neonate blood samples were obtained at vaginal delivery in order to measure leptin and the somatotropin axis components. Results: In all cases maternal blood concentrations of leptin, t and fIGF-I, its carrier protein IGFBP-3, and insulin were higher than in the cord sera of the newborns, regardless of their birth weight. On the contrary, maternal GH levels were lower than in their neonates. LBW neonates had decreased levels of leptin, tIGF-I, and IGFBP-3 as compared with those levels in NBW offspring; however, GH concentrations were higher in LBW neonates. Birth weight showed a significant correlation with cord sera leptin, tIGF-I, IGFBP-3, and GH; nevertheless birth weight was neither interrelated with fIGF-I nor with insulin levels. Conclusion: These data demonstrate that birth weight is significantly correlated with both leptin and some components of the somatotropin axis; on the other hand, no correlation was observed between leptin concentrations and each one of the components of the somatotropin axis. It is suggested that fetal leptin and the somatotropin axis cooperate in intrauterine growth and birth weight.

Elevation of activity of creatine phosphokinase (CK) and its isoenzymes in the newborn is associated with fetal asphyxia and risk at birth

OBJECTIVE To investigate the relationship of creatine phosphokinase and its isoenzymes with fetal asphyxia and risk at birth. METHODS Thirty-five pregnant women with high-risk pregnancy were studied. RESULTS In 21 patients, fetal distress was diagnosed by interpretation of the fetal heart rate tracing (FHR). The remaining 14 women, having normal fetal cardiotocography, were considered as the control group. Total CK and its isoenzymes activity was measured in cord sera and 24 h after birth in peripheral blood. Abnormal FHR patterns correlate well with elevated enzyme activities. Total CK and its isoenzymes (CK-MM, CK-MB, and CK-BB) exhibited higher values in asphyxiated infants as compared to normal neonates. Electrocardiographic ischemia occurred in seven newborns who had elevated CK-MB and CK-BB levels, both at birth and within 24 h postpartum. Chromatographic study showed in normal neonates that the predominant isoenzyme was CK-MM, whereas CK-BB activity was negligible. In the newborns with abnormal FHR, CK-MB and CK-BB were increased with predominance of CK-MB. CONCLUSIONS Antepartum fetal distress is associated with release of CK-BB, and particularly CK-MB; therefore, these biochemical markers may indicate either brain or myocardial damage.

Effect of Estrogen Therapy on Insulin Resistance and Plasminogen Activator Inhibitor Type 1 Concentrations in Postmenopausal Women

Background/Aims: An elevated thrombotic risk due to abnormal fibrinolysis might be associated with insulin resistance in postmenopause. The aim of this study was to investigate the association of insulin resistance with a biochemical marker of fibrinolysis as well as the effect of transdermal estrogen treatment (ET) on this association. Methods: Thirty postmenopausal hysterectomized women received transdermal estradiol during 3 months. 17β-Estradiol, FSH, LH, plasminogen activator inhibitor type 1 (PAI-1), insulin and glucose were measured in blood samples before and after ET. Insulin resistance was calculated by the use of the homeostasis model assessment for insulin resistance (HOMA-IR).Results:ET induced a significant decrement in both PAI-1 levels and HOMA-IR values. The study also showed that HOMA-IR was a significant predictor for PAI-1 concentrations. Conclusion: Short-term ET improved HOMA-IR values in parallel with a decrease in PAI-1 levels.

Expression of Growth Hormone Receptor Isoform Exon-3-Excluding and Exon-3-Retaining Messenger RNAs in Peripheral Lymphocytes from Normal and Acromegalic Subjects

Aim: To determine the expression of two isoforms of the growth hormone (GH) receptor (GHR), which differ by the presence (GHR3+) or absence (GHR3–) of exon 3, and their correlation with circulating GH and insulin-like growth factor I (IGF-I) in normal subjects and in acromegalic patients. Methods: The expression of GHR isoforms was determined by reverse-transcriptase polymerase chain reaction in lymphocytes from 12 normal subjects and from 11 patients with acromegaly. The levels of GHR mRNA were normalized to those of β-actin, and ratios were calculated to assess the relative levels of expression. Results: All samples showed expression of both GHR isoforms, but the expression of GHR3+ and GHR3– was similar in acromegalic patients (6.0 ± 1.7 vs. 8.3 ± 2.0%, mean ± SE). In contrast, in healthy subjects, GHR3– was the predominant isoform (11.8 ± 3.0 vs. 5.1 ± 0.68%; p < 0.05), and the levels of expression of GHR3– correlated significantly with IGF-I. Conclusions: These data demonstrate coexpression of both GHR isoforms under normal and pathological conditions; however, GHR3– is the predominant form in normal subjects and shows a negative correlation with IGF-I levels.

Effect of naloxone on serum prolactin levels in adult male rabbits.

In order to clarify the possible physiological role of endogenous opioid peptides (EOP), we studied the effect of low doses of naloxone (specific opiate antagonist) on plasma prolactin levels in male rabbits. Five groups of five male rabbits each was injected daily between 8-9 a.m., with naloxone 12.5, 25, 50, 100 and 200 microg/kg/day. An additional group of ten animals was injected with saline solution and considered the control group. Blood samples were taken at baseline before naloxone administration and later at 90 min and 1, 2, 4, 7, 10 days after its administration. Samples were also taken 4 days after stopping naloxone administration (day 14). Plasma prolactin levels were measured by RIA. A significant constant decrease in PRL levels was seen with the 12.5 microg at 90 minutes, while with the remaining doses a progressive decrease was recorded throughout the study.