INCREASE OF MOUSE LEPTIN PRODUCTION BY ADIPOSE-TISSUE AFTER MIDPREGNANCY - GESTATIONAL PROFILE OF SERUM LEPTIN CONCENTRATION

The serum concentration of leptin in 10 week old virgin ICR mice asses sed by RIA was 1.70 +/- 0.08 ng/ml. The serum leptin concentration in the pregnant mice mated at 10 weeks of age significantly increased fro m day 11 of pregnancy and reached a peak on day 17 of pregnancy (42.2 +/- 4.8 ng/ml). After the delivery, the serum leptin concentration rap idly decreased and reached the level of the virgin mouse on the sevent h day in the puerperium. Tissue contents of leptin in the placenta, th e decidua, the uterus, and the adipose tissue were between 40 to 130 n g/g wet tissue, However, leptin mRNA was expressed only in the adipose tissue and the level of leptin mRNA on days 13 and 17 of pregnancy in creased 3- to 5-fold compared with that of virgin mouse. Tissue conten t of leptin in the adipose tissue significantly increased from day 17 of pregnancy compared with that of the virgin mouse, The m-leptin secr etion from the adipose tissue also significantly increased in vitro. T hese results suggest that leptin, which was secreted by adipose tissue , may play important roles in mouse reproduction after midpregnancy. ( C) 1997 Academic Press.