This hormone is normally secreted by adipocytes. It functions as an antiobesity hormone that decreases food intake .through its hypothalamic receptor. It also regulates bone growth and immune unction (Cock, 2003; La Cava, 2004). In the placenta, leptin is synthesized by both cytotrophoblasts and syncytiotrophoblast (Henson, 2002). Relative contributions of leptin from maternal adipose tissue versus placenta are currently not well defined, although recent evidence highlights a key regulatory role of placental leptin in placental amino acid transport and fetal growth (Rosario, 20 16a). Maternal serum levels are significantly higher than those in nonpregnant women. Fetalileptin levels correlate positively with birth weight and likely function in fetal development and growth. Studies suggest that reductions in leptin availability contribute to adverse fetal metabolic programing in intrauterine growth-restricted ofspring (Nusken, 2016).
This 36-amino-acid peptide is widely distributed in brain. It also is found in sympathetic neurons innervating the cardiovascular, respiratory, gastrointestinal, and genitourinary systems. Neuropeptide Y has been isolated from the placenta and localized in cytotrophoblasts (Petraglia, 1989). Trophoblasts possess neuropeptide Y receptors, and treatment of these with neuropeptide Y causes CRH release (Robidoux, 2000).
hese glycoprotein hormones are expressed in male and female reproductive tissues and belong to the transforming growth factor-� family Gones, 2006). Inhibin is a heterodimer made up of one a-subunit and one of two distinct �-subunits, either �A or �B. his yields either inhibin A or inhibin B, respectively. Activin is formed by the combination of the two �-subunits. Activin, inhibin, and their respective receptors are expressed in the placenta. Both activin and inhibin A have proposed functions during cytotrophoblast fusion into the syncytiotrophoblast (Debieve, 2000; Jones, 2006). Activin also stimulates production of placental hormones such as hCG, hPL, progesterone, and estrogen (Luo, 2002; Morrish, 1991; Petraglia, 1989; Song, 1996). Inhibin A opposes activin action in the placenta to inhibit production of hCG and steroidogenesis (Petraglia, 1989). Abnormal levels of inhibin or activin correlate with placental pathologies. For example, elevation in inhibin A levels in the second trimester is indicative of fetal Down syndrome. Further, low inhibin levels early in pregnancy may indicate pregnancy failure (Prakash, 2005; Wallace, 1996). Elevations in circulating inhibin and activin levels are reported in women with preeclampsia (Bersinger, 2003).
After 6 to 7 weeks' gestation, little progesterone is produced in the ovary (Diczfalusy, 1961). Surgical removal of the corpus luteum or even bilateral oophorectomy during the 7th to 10th week does not decrease excretion rates of urinary pregnanediol, 100.0 50.0 10.0 n ..) 5.0 1.0 ):l u 0.5 0.1 0.05