Leptin receptor transcripts are constitutively expressed in placenta and adipose tissue with advancing baboon pregnancy

The baboon (Papio sp.) is an accepted nonhuman primate model for the study of the endocrinology of human pregnancy. To further characterize this model with regard to leptin function, messenger RNA transcripts for both long (O b-RL) and short (Ob-RS) leptin receptor isoforms were identified in materna l tissues at various stages of gestation. Thus, placental villous, subcutan eous and omental adipose tissues were collected upon cesarean delivery at e arly (Days 60-62), mid (Days 98-102) and late (Days 159-164) pregnancy (ter m approximate to 184 days). Additionally, amniochorion, decidua, and corpus luteum were collected in late gestation. Expression of Ob-RL and Ob-RS tra nscripts was determined in relation to constitutively expressed glyceraldeh yde-3-phosphate dehydrogenase via reverse transcriptase-polymerase chain re action, and transcripts were localized within specific placental cell types by in situ hybridization. Ob-RL and Ob-RS transcripts were present in amni ochorion, decidua, and corpus luteum at term and appeared constitutively ex pressed throughout gestation in placenta and adipose tissues. Ob-RS was exp ressed in greater (P < 0.02) abundance than Ob-RL in all tissues. Within th e placenta, receptor isoforms were localized predominantly to the syncytiot rophoblast. The expression of leptin receptor transcripts in maternal adipo se tissues, as well as in the syncytiotrophoblast, amniochorion, decidua, a nd corpus luteum, suggests the potential for autocrine/paracrine roles for the polypeptide in the endocrinology of primate pregnancy. These are the fi rst such observations in a nonhuman primate and support the use of the babo on as a model for the study of leptin in human pregnancy.