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AE Green1 2 *, JS O'Neil1 2 *, KF Swan1 , MC Henson1 2 *
Tulane University School of Medicine, Depts of Obstetrics and Gynecology, New Orleans, Louisiana 1
Tulane University School of Medicine, Molecular and Cellular Biology, New Orleans, Louisiana 2
Leptin, originally assumed to be exclusively produced by adipocytes, is a 16 Kd protein that regulates adipose homeostasis via a hypothalamic receptor. The leptin receptor exists as alternatively spliced isoforms, which differ in the length of their intracellular domains. They include a long form (Ob-RL), which has JAK/Stat signaling capabilities and a short form (Ob-RS), whose function is currently undetermined. Leptin receptor isoforms have also been identified in adipocytes, in the ovary and in the human placenta. The presence of both leptin and its receptor in the placenta suggest a potential role in pregnancy. Because of difficulties in collecting tissues during human gestation, validation of a nonhuman primate model would be efficacious for investigating leptin receptor function in pregnancy. Therefore, in the present study, placental villous tissue, corporea lutea, subcutaneous fat and omental fat were collected upon cesarean section from baboons (Papio sp), at early (day 60, n=5), mid (day 100, n=5), and late (day 160, n=5) pregnancy (term 184 days). Expression of both Ob-RL and Ob-RS transcripts, in relation to constitutively-expressed glyceraldehyde-3-phosphate dehydrogenase, was detected in all tissues by RT-PCR. No differences (P > 0.05) were detected in transcript abundance with advancing gestation in placenta or adipose tissue. In situ hybridization localized placental leptin receptor transcripts to the syncytiotrophoblast, suggesting the potential for autocrine/paracrine signaling mechanisms in this endocrinologically-active tissue. Ours are the first such observations made in a nonhuman primate and suggest the baboon to be a viable model for the study of the leptin receptor in pregnancy. Supported by NIH R29 HD32502.
This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.