LEPTIN IN HUMAN-PREGNANCY - THE RELATIONSHIP WITH GESTATIONAL HORMONES

OBJECTIVES: The aims of the study were (1) to examine the relationship between leptin and placental hormones by measuring serial changes in serum levels of leptin during and after pregnancy and (2) to study the effects of several gestational hormones on leptin release from fully differentiated 3T3-L1 adipocyte cell cultures. STUDY DESIGN: Serum lev els of leptin were measured throughout pregnancy and at 3 months post partum in 29 healthy women and were also measured in 18 healthy women at delivery by cesarean section and on postpartum day 3. In addition, 3T3-L1 mouse adipocytes were incubated for 24 hours in media containin g various reproductive hormones and leptin production was measured. RE SULTS: Serum leptin levels increased significantly (8.4 +/- 0.9 vs 13. 5 +/- 1.5 ng/mL; P < .001) between the first 2 trimesters of pregnancy but not between the second and third trimesters. These changes in lep tin did not correlate significantly with changes in body mass index. L eptin levels dropped significantly during the immediate postpartum per iod, from 34.1 +/- 4.9 at cesarean delivery to 7.3 +/- 1.4 ng/mL on po stpartum day 3 (P < .001). Fasting insulin level did not correlate sig nificantly with leptin level during pregnancy but did so during the po stpartum period (r = 0.60; P < .05). Leptin secretion from 3T3-L1 adip ocytes was increased significantly when cells were cultured with human chorionic gonadotropin (150%, P < .01) and also when they were cultur ed with estrogen (120%, P < .03). CONCLUSION: The data suggest that le ptin production by adipose tissue is stimulated by several hormones of pregnancy, which may contribute to the increased leptin levels observ ed during gestation.