Leptin and leptin receptor mRNA and protein expression in the murine fetus and placenta

Abstract

Leptin is a 167-aa protein that is secreted from adipose tissue and is important in the regulation of energy balance. It also functions in hematopoiesis and reproduction. To assess whether leptin is involved in fetal growth and development we have examined the distribution of mRNAs encoding leptin and the leptin receptor (which has at least six splice variants) in the 14.5-day postcoitus mouse fetus and in the placenta using reverse transcription-PCR and in situ hybridization. High levels of gene expression for leptin, the leptin receptor, and the long splice variant of the leptin receptor with an intracellular signaling domain were observed in the placenta, fetal cartilage͞bone, and hair follicles. Receptor expression also was detected in the lung, as well as the leptomeninges and choroid plexus of the fetal brain. Western blotting and immunocytochemistry, using specific antibodies, demonstrated the presence of leptin and leptin receptor protein in these tissues. These results suggest that leptin may play a role in the growth and development of the fetus, both through placental and fetal expression of the leptin and leptin receptor genes. In the fetus, leptin may be multifunctional and have both paracrine and endocrine effects.

Leptina: o diálogo entre adipócitos e neurônios

“…O receptor Ob-Rb faz parte da família de receptores das citoquinas, ativando o sistema JAK/STAT de transdução do sinal após sua ligação com a leptina (24). A forma longa do receptor foi encontrada nos mais diversos órgãos incluindo pâncreas, rim, medula adrenal, placenta, ovários e tecido adiposo (25)(26)(27). Uma forte presença da expressão do gene do receptor Ob-Rb é vista nos diversos núcleos hipotalâmicos que regulam a ingestão alimentar e o controle do gasto energético (28).…”

The intake of physiological doses of leptin during lactation in rats prevents obesity in later life

“…In fact, the administration of this hormone, while proven to be effective in reducing fat and normalizing metabolic disorders in leptin-deficient mice and humans, has not proven to be effective in most cases of obesity. 4,[8][9][10] Although leptin is mainly produced by the adipose tissue, this hormone is also produced by other tissues, such as stomach, [11][12][13] placenta, 14,15 skeletal muscle 16 and mammary epithelium, 17 and it is naturally present in maternal milk. 18,19 Although leptin produced by the adipose tissue is known to play a main role in the chronic control of energy balance, the role of leptin produced by the stomach has been related with the short-term control of food intake, acting as a satiety signal.…”

Leptin and cancer

“…The other leptin sources include gastric mucosa cells (Bado et al, 1998), mammary epithelial cells (Smith-Kirwin et al, 1998), myocytes (Wang et al, 1998), and the placenta (Senaris et al, 1997). Leptin expression has also been reported in the testes, ovary, and hair follicles (Hoggard et al, 1997). Subsequent studies documented that in addition to its primary function as a regulator of food intake, leptin can affect fetal development, sex maturation, lactation, hematopoiesis, and immune responses (Wauters et al, 2000;Bonnet et al, 2002;Brann et al, 2002;Neville et al, 2002;Goumenou et al, 2003).…”