Serum Leptin Levels Do Not Rise during Pregnancy in Age-Matched Rats

Terada, Yasuhiko; Yamakawa, Kensuke; Sugaya, Ayumi; Toyoda, Nagayasu

doi:10.1006/bbrc.1998.9861

Cited by 40 publications

(30 citation statements)

References 15 publications

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“…In the mouse serum leptin increases by 25 times (Tomimatsu et al, 1997) on day 17 of pregnancy in the maternal circulation compared with a 2.7-fold and 1.8-fold maximum rise in humans (Hardie et al, 1997) and rats (Chien et al, 1997), respectively. However, in contrast to these observations, Terada et al (1998) suggest that in age-matched rats maternal leptin concentrations remain unchanged until day 20 of pregnancy when they decrease. The relative contribution of adipose and placental-derived leptin to circulating concentrations in rodents is uncertain.…”

Section: Functioncontrasting

confidence: 70%

“…The human placenta contains substantial amounts of leptin mRNA and protein (Masuzaki et al, 1997). Comparable amounts of immunoreactive leptin occur in the rodent placenta, although expression of rodent placental leptin mRNA appears to be much lower than in humans (Hoggard et al, 1997a;Tomimatsu et al, 1997;Terada et al, 1998). The significance of this species difference remains to be determined.…”

Section: Localizationmentioning

confidence: 96%

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Placental leptin

Ashworth¹,

Hoggard²,

Thomas³

et al. 2000

Reviews of Reproduction

175

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Section: Functioncontrasting

confidence: 70%

Section: Localizationmentioning

confidence: 96%

Placental leptin

Ashworth¹,

Hoggard²,

Thomas³

et al. 2000

Reviews of Reproduction

175

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“…The high levels of maternal leptin serum throughout pregnancy and its decline drastically postpartum suggests a functional importance of leptin during pregnancy. One study reported, however, that pregnancy induced increases in plasma leptin are not evident if compared to the non pregnant control rats (Terada et al, 1998).…”

Section: Serum Leptin Levels Throughout Pregnancy and After Parturitimentioning

confidence: 95%

“…Comparable amounts of immunoreactive leptin occur in the rodent placenta, although expression of rodent placental leptin mRNA appears to be much lower than in humans (Hoggard et al, 1997;Kawai et al, 1997;Tomimatsu et al, 1997;Terada et al, 1998). Importantly, the rodent placenta appears to contribute little, if any, leptin to the maternal circulation (Kawai et al, 1997;Hoggard et al, 2000).…”

Section: Expression Of Leptin Rna In the Placenta During Pregnancy Inmentioning

confidence: 99%

Leptin Gene Expression in Rabbits During Pregnancy and Fetal Life

Kirat¹,

Hamid²,

Mohamed³

et al. 2015

IJB

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Leptin may act as the critical link between adipose tissue and reproduction. Although considerable progress has been achieved in understanding the reproductive actions of leptin, much work is needed for understanding its physiological role. Till now, no data has been published about the distribution and expression levels of leptin in the rabbit maternal adipose tissue, placenta, and various fetal rabbit tissues during pregnancy and postpartum. Our results indicated that circulating leptin levels in rabbit serum during pregnancy were significantly higher than in postpartum and non pregnant rabbits. Furthermore, leptin showed positive correlations with body weight and estrogen and negative correlation with progesterone in pregnant and postpartum rabbits. RT-PCR verified the presence of RNAs encoding leptin in the rabbit maternal perirenal adipose tissue, placenta, and several fetal tissues; including brain, liver, adipose tissue, and bone. The relative abundance of leptin RNA in rabbit maternal adipose was significantly higher at 20 th day of pregnancy than that of non pregnant rabbits, while it was significantly decreased at 2 nd day after parturition. No significant changes in the placental leptin RNA levels were noticed in pregnant rabbits at 10 th , 20 th , and 30 th day of pregnancy. The relative abundance of fetal leptin transcripts at day 30 th of pregnancy was in the order of liver> bone ≥ adipose tissue > brain. The present study provides new evidence for the distribution and expression levels of leptin in the rabbit maternal and fetal tissues during pregnancy and supports the importance of leptin in reproductive physiology and fetal development.

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“…Key targets are neurons in the hypothalamic arcuate nucleus (ARC) expressing the signaling form of the leptin receptor (OB-Rb); these are the orexigenic peptides neuropeptide Y (NPY) and agouti-related peptide (AGRP) and the anorexigenic peptides proopiomelanocortin (POMC, precursor for melanocortins) and cocaine-and amphetamine-regulated transcript (CART) (4,5,31,62,64,72). Adipose leptin gene expression and serum leptin concentrations are reported to be reduced during lactation in the monogastric rat in most (16,36,39,56,65,74), but not all (17,19,61), studies. NPY (18,21,43,44,54,55,63,71) and AGRP (18) are upregulated, and POMC is downregulated (54,63) in the hypothalamus during lactation in the rat.…”

mentioning

confidence: 99%

Leptin secretion and hypothalamic neuropeptide and receptor gene expression in sheep

Sørensen

Adam²,

Findlay³

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

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Sheep were fed ad libitum and killed at 6 and 18 days of lactation; ad libitum-fed nonlactating sheep were killed as controls. Despite increased food intake, lactating ewes were in negative energy balance. Lactation decreased plasma leptin and adipose tissue leptin mRNA concentrations. OB-Rb gene expression, determined by in situ hybridization, was increased in the hypothalamic arcuate nucleus (ARC) and ventromedial hypothalamic nucleus (VMH) at both stages of lactation. Neuropeptide Y (NPY) was increased by lactation in both the ARC and dorsomedial hypothalamus (DMH), although increased gene expression in the DMH was only apparent at day 18 of lactation. Gene expression was decreased for cocaine-and amphetamine-regulated transcript (CART) in the ARC and VMH and for proopiomelanocortin in ARC during lactation. Agouti-related peptide gene expression was increased in the ARC, and melanocortin receptor expression was unchanged in both the ARC and VMH with lactation. Thus the hypoleptinemia of lactation may activate NPY orexigenic pathways and attenuate anorexigenic melanocortin and CART pathways in the hypothalamus to promote the hyperphagia of lactation. hypothalamic neuropeptides; appetite NUTRIENT REQUIREMENTS ARE markedly increased during lactation to meet the demands for milk production (7,70). In most mammals, these additional requirements are met primarily by increasing food intake (7,20,70), but factors regulating the hyperphagia of lactation are not well understood. In addition, in many species, the increased intake is insufficient to meet the metabolic demands, resulting in a state of negative energy balance during early lactation when body lipid reserves are mobilized (7,69). In some species such as the rat, the degree of negative energy balance is usually slight, with animals mobilizing ϳ1 g fat/day (7). Domestic ruminants, however, usually exhibit a greater degree of negative energy balance during early lactation (7, 11), which can impact on their welfare and productivity (28), yet the regulatory mechanisms have not been elucidated.It is postulated that leptin, a peptide hormone secreted by adipose tissue (75), could play a role in the hyperphagia of lactation. Leptin acts on hypothalamic neuronal systems to regulate energy balance and neuroendocrine function; in particular, a reduction in circulating leptin is a potent signal of negative energy balance, activating compensatory orexigenic pathways in the hypothalamus (3-5, 35, 64). Key targets are neurons in the hypothalamic arcuate nucleus (ARC) expressing the signaling form of the leptin receptor (OB-Rb); these are the orexigenic peptides neuropeptide Y (NPY) and agouti-related peptide (AGRP) and the anorexigenic peptides proopiomelanocortin (POMC, precursor for melanocortins) and cocaine-and amphetamine-regulated transcript (CART) (4,5,31,62,64,72). Adipose leptin gene expression and serum leptin concentrations are reported to be reduced during lactation in the monogastric rat in most (16,36,39,56,65,74), but not all (17,19,61), studies. NPY (18,21,...

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Serum Leptin Levels Do Not Rise during Pregnancy in Age-Matched Rats

Cited by 40 publications

References 15 publications

Placental leptin

Placental leptin

Leptin Gene Expression in Rabbits During Pregnancy and Fetal Life

Leptin secretion and hypothalamic neuropeptide and receptor gene expression in sheep

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