To explore the hypothesis that FS-inhibin/activin complexes are present in tissues and biological fluids, recombinant proteins (FS288, rh-activin A, and rh-inhibin A) were assembled in vitro and analyzed by gel mobility in order to compare the molecular sizes of the in vitro-gen-erated complexes to those of naturally occurring FS-con-taining proteins. Our data point to the assembly of FS-ac-tivin and FS-inhibin complexes that correspond to proteins detected in tissue homogenates. We chose the pituitary, the ovary, and the kidney since these are organs in which FS production and message have been clearly demonstrated in the past. Our observations explain, in part, the array of FS molecules identified in previous studies. antibiotic levaquin
Bilezikjian et al. detected protein bands at greater than 200 kDa, 90-100 kDa, 50-55 kDa, and 42-44 kDa from anterior pituitary lysates. When rh-FS288 was added to the lysate samples, the antibodies preferentially bound the recombinant ligand, and subsequently the higher molecular weight proteins were not detected. While the lower molecular size proteins were suggested to be variants of FS processing, no explanation was given for the larger proteins.