Fluctuation of Serum Apelin Level during Pregnancy

Abstract

Background: Apelin is an endogenous ligand for the G protein-coupled receptor Apelin receptor (APJ), The expression of both apelin and APJ has been detected in a variety of tissues including  heart, brain ,ovary , placenta and uterus. Aim of the Study: This study was designed to examine the circulating levels of apelin, estradiol, progesterone, glucose, insulin and Tumor necrosis Factor alpha (TNF α)  in non-pregnant, pregnant rats at different stages of  pregnancy. Materials and Methods: Sixty adult albino rats (48 females and 12 males). Female rats were randomly divided into (non -pregnant rats, early pregnant rats on day 6 of gestation, mid pregnant rats on day 12 of gestation and rats late pregnant rats on day 19 of gestation. The blood samples were obtained from the orbital venous plexus of animals and serum was separated from each blood sample and kept deep frozen until analysed. Results: The present study revealed that the serum levels of apelin were progressively  and significantly increased from early (day 6) to mid-pregnancy (day 12) of gestation when compared to non- pregnant rats then showed a marked decrease on day 19 when compared to pregnant rats on day 12 of gestation. Conclusion: The fluctuations in serum apelin levels during pregnancy may be attributed to changes in serum levels of multiple interrelated factors such as insulin, insulin resistance, pro inflammatory cytokines such as TNF α and other factors such as changes in fat mass, the  expression of angiotensin converting enzyme related carboxy peptidase-2 (ACE 2) and hormonal levels during pregnancy.