Changes in body mass, serum leptin, and mRNA levels of leptin receptor isoforms during the premigratory period in Myotis lucifugus

We investigated the effects of lactation on diurnal changes in serum leptin and hypothalamic expression of the leptin receptor isoforms, Ob-Ra, -Rb, -Rc, -Re and -Rf in rats. In non-lactating rats, serum leptin concentration was increased at night while hypothalamic mRNA levels of Ob-Rb, -Rc and -Re decreased; by contrast, expression of Ob-Ra and Ob-Rf was unchanged at night. There were significant negative correlations between serum leptin and mRNA expression of Ob-Rb (P<0.001) and Ob-Re (P<0.05), which were independent of time of day. In lactating rats, the nocturnal rise in serum leptin was attenuated. Daytime hypothalamic Ob-Rb mRNA levels were significantly lower than in non-lactating controls, and the normal nocturnal decreases in expression of Ob-Rb, -Rc and -Re were lost. The relationship between serum leptin and Ob-Re expression was not changed by lactation. Lactation had no effect on the expression of Ob-Ra mRNA in the hypothalamus. Decreased daytime Ob-Rb expression could lead to reduced hypothalamic sensitivity to leptin, and thus contribute to increased daytime appetite in lactating rats. Moreover, maintaining high levels of Ob-Re expression could, by increasing hypothalamic leptin-binding protein concentration and reducing local leptin bioavailability, further accentuate hyperphagia. Thus, selective changes in expression of specific isoforms of the leptin receptor may contribute to the hyperphagia of lactation in rats.

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Suppression of Leptin Receptor Messenger Ribonucleic Acid and Leptin Responsiveness in the Ventromedial Nucleus of the Hypothalamus during Pregnancy in the Rat

Endocrinology ◽

10.1210/en.2005-0194 ◽

2005 ◽

Vol 146 (9) ◽

pp. 3868-3874 ◽

Cited By ~ 81

Author(s):

S. R. Ladyman ◽

D. R. Grattan

Keyword(s):

Choroid Plexus ◽

Arcuate Nucleus ◽

Leptin Receptor ◽

Leptin Resistance ◽

Ventromedial Nucleus ◽

Mrna Levels ◽

Pregnant Rats ◽

Messenger Ribonucleic Acid ◽

Leptin Receptors ◽

Receptor Isoforms

Abstract Pregnancy in the rat is a state of leptin resistance associated with impaired leptin signal transduction in the hypothalamus. The aim of this study was to determine whether this leptin-resistant state is mediated by a change in the level of leptin receptors in the hypothalamus. Real-time RT-PCR was used to determine levels of mRNA for the various leptin receptor isoforms in a number of microdissected hypothalamic nuclei and the choroid plexus. To investigate the functional activation of the leptin receptor, immunohistochemistry for phosphorylated signal transducer and activator of transcription 3 (pSTAT3) was examined in the arcuate nucleus and the ventromedial nucleus of the hypothalamus (VMH) of fasted diestrous and d-14 pregnant rats after an intracerebroventricular (i.c.v.) injection of either leptin (4 μg) or vehicle. A significant reduction of Ob-Rb mRNA levels was observed in the VMH during pregnancy compared with the nonpregnant controls. Furthermore, in pregnant rats the number of cells positive for leptin-induced pSTAT3 in the VMH was greatly reduced during pregnancy compared with nonpregnant rats. There were no differences in the level of Ob-Rb mRNA or in the number of leptin-induced pSTAT3-positive cells in the arcuate nucleus of nonpregnant and pregnant rats. These data implicate the VMH as a key hypothalamic site involved in pregnancy-induced leptin resistance. There were also reduced levels of mRNA for Ob-Ra, a proposed leptin transporter molecule, in the choroid plexus on d 7 and 21 of pregnancy. Hence, diminished transport of leptin into the brain may also contribute to pregnancy-induced leptin resistance.

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Serum leptin and weight reduction in female obesity

Acta Endocrinologica ◽

10.1530/eje.0.1350659 ◽

1996 ◽

Vol 135 (6) ◽

pp. 659-662 ◽

Cited By ~ 38

Author(s):

R Geldszus ◽

B Mayr ◽

R Horn ◽

F Geisthövel ◽

A von zur Mühlen ◽

...

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Weight Reduction ◽

Leptin Receptor ◽

High Body Mass Index ◽

Normal Weight ◽

Normal Diet ◽

Calorie Intake ◽

Obese Women ◽

Serum Leptin

Geldszus R, Mayr B, Horn R, Geisthövel F, von zur Mühlen A, Brabant G. Serum leptin and weight reduction in female obesity. Eur J Endocrinol 1996;135:659–62. ISSN 0804–4643 Leptin, an adipocyte-derived hormone, induces a decrease in food intake and increases energy expenditure via hypothalamic interactions. In animal models obesity can be caused by leptin deficiency or by a dysfunction of the hypothalamic leptin receptor. Using a radioimmunoassay for the determination of leptin in human serum, we measured serum leptin levels in 227 otherwise healthy normal weight (N = 78; body mass index = 16.1–27.7 kg/m2) or obese women (N = 149; body mass index = 27.8–56.7 kg/m2). Fifty-three subjects were followed over a period of 12 weeks under weight reduction (800 kcal/day) and a subgroup of 33 for another 13 weeks after termination of the diet. Body mass index and serum leptin concentrations were measured longitudinally and compared to female controls not under diet. Under baseline conditions, log serum leptin levels were positively related to body mass index with a best fit using a non-linear regression (p < 0.001), indicating an attenuated increase in serum leptin levels with high body mass index. No subgroup with low serum leptin levels could be identified. Weight reduction induced a rapid decrease in serum leptin levels within the first 3 weeks to levels significantly lower than in body mass index-matched controls under normal diet (p < 0.001). This pattern was consistent after 6 and 12 weeks. Serum leptin levels increased again after the end of the diet but remained significantly lower than in the controls despite unrestricted calorie intake over 7 weeks. The rapid and persistent decrease in serum leptin to lower levels than expected from matched controls may explain the pertinent difficulties of obese subjects to cope with weight reduction. G Brabant, Abt. Klinische Endokrinologie Medizinische Hochschule Hannover, Konstanty-Gutschowstr. 8, D-30623 Hannover, Germany

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Role of hypoleptinemia during cold adaptation in Brandt's voles (Lasiopodomys brandtii)

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00185.2009 ◽

2009 ◽

Vol 297 (5) ◽

pp. R1293-R1301 ◽

Cited By ~ 15

Author(s):

Gang-Bin Tang ◽

Jian-Guo Cui ◽

De-Hua Wang

Keyword(s):

Food Intake ◽

Cold Adaptation ◽

Leptin Receptor ◽

Uncoupling Protein ◽

Cytokine Signaling ◽

Mrna Levels ◽

Serum Leptin ◽

Brown Adipose ◽

Lasiopodomys Brandtii

Brandt's voles Lasiopodomys brandtii exhibit large increases in nonshivering thermogenesis to cope with chronic cold exposure, resulting in compensatory hyperphagia and fat mobilization. These physiological events are accompanied by a remarkable reduction in serum leptin levels. However, the role of hypoleptinemia in cold adaptation in this species is still unknown. In the present study, we tested the hypothesis that hypoleptinemia contributes to increases in food intake and brown adipose tissue (BAT) thermogenesis by modifying hypothalamic neuropeptides in cold-exposed Brandt's voles. Adult male voles were transferred to 5°C for 28 days. Accompanied by a decrease in serum leptin levels, hypothalamic agouti-related protein (AgRP) mRNA levels were significantly increased, but there were no changes in the long form of leptin receptor (Ob-Rb), suppressor of cytokine signaling 3 (SOCS3), neuropeptide Y (NPY) mRNA, proopiomelanocortin (POMC), and cocaine- and amphetamine-regulated peptide (CART) mRNA levels in the hypothalamus. When cold-exposed voles were returned to warm (23°C) for 28 days, body mass, food intake, serum leptin, and AgRP mRNA were restored to control levels. Leptin administration in cold-exposed voles decreased food intake as well as hypothalamic AgRP mRNA levels. There were no significant effects of leptin administration on hypothalamic Ob-Rb, SOCS3, NPY, POMC, CART mRNA, and uncoupling protein 1 levels under cold conditions. These results suggest that hypoleptinemia partially contributes to cold-induced hyperphagia, which might involve the elevation of hypothalamic AgRP gene expression.

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Relationship between Leptin Concentration in Cord Blood and Foetal Growth and Maternal Anthropometry of GDM Mothers at Delivery

Journal of Bangladesh College of Physicians and Surgeons ◽

10.3329/jbcps.v25i1.166 ◽

1970 ◽

Vol 25 (1) ◽

pp. 9-13

Author(s):

S Jahan ◽

TR Das ◽

KB Biswas

Keyword(s):

Body Mass Index ◽

Birth Weight ◽

Cord Blood ◽

Body Mass ◽

Anthropometric Measurements ◽

Anthropometric Parameters ◽

Serum Leptin ◽

C Peptide ◽

Cord Serum ◽

The Relationship

Background and Aims: Cord blood leptin may reflect the leptinemic status of a newborn at birth more accurately than the leptin values of blood collected from other sites. The present study was undertaken to determine the relationship of cord serum leptin concentration at birth with neonatal and maternal anthropometric parameters. Materials and Methods: Blood was taken from the umbilical cord of the babies at delivery. Maternal anthropometric measurements were recorded at admission for delivery. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between cord serum leptin concentration and anthropometric parameters of the baby and the mother. Both Serum leptin and serum C-peptide levels were measured by chemiluminescence-based ELISA method. Results: The leptin concentration (ng/ml, mean±SD) in cord blood was 39.13±14.44. Cord leptin levels correlated with birth weight (r=0.673, p<0.0001), ponderal index (r=0.732, p<0.0001) but it did not correlate with maternal body mass index, gestational age (r=0.135, p=0.349) at delivery or cord serum C-peptide concentration (r=-0.049, p=0.735) or placental weight (r=0.203, p=0.157). Conclusion: There are associations between cord leptin concentration at delivery and birth weight, ponderal index (PI) of the babies but not body mass index (BMI) of the mothers. High leptin levels of the baby could represent an important feedback modulator of substrate supply and subsequently for adipose tissue status during late gestation. (J Bangladesh Coll Phys Surg 2007; 25 : 9-13)

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