Reagents and Sample Collection
Recombinant human (rh) activin A and rh-FS288 were provided through the National Pituitary and Sormone Distribution Program (Rockville, MD) of the NIH. Recombinant human inhibin A was generated in the laboratory. Antibodies that recognize FS, activin, and inhibin used in this study have been previously described. Normally cycling and timed-pregnant Sprague-Dawley-derived female rats were obtained from Harlan BioSciences (Indianapolis, IN). The animals were maintained on a 14L:10D schedule with constant access to food and water prior to and during the study. All animal experimentation was conducted in accordance with the NIH Guide for the Care and Use of Laboratory Animals. buy birth control online
The collection of urine from pregnant women was approved by the Northwestern Medical School Institutional Review Board review committee. Third-trimester urine samples were collected from healthy pregnant women at their routine prenatal visits. Nonpregnant female urine and male urine samples were collected from volunteers. All samples were centrifuged to remove sediment and stored at -80°C. Separate aliquots were used in each assay. Urine samples were concentrated using Mi-crosep-10 microconcentrators (Filtron Technology [Pall Gelman Sciences, Ann Arbor, MI]).