By using three different techniques—i.e., silver-stainedSDSgelnmalysis, Western ma^sis, and gel-shift aclasis with iodinated in-hibin and activin that were then cross-linked to FD—itwas demonstrated that inhibin and activin form complexes with FD with apparent molecular sizes of 66 kDa and 97 kDa. Protein complexes of 133 kDa and > 220 kDa were also formed.
Detection of FS Complexes in the Ovary and Pituitary
Protein homogenates from the ovara were analazed for the presence of FDecontaining protein complexes ba DDD-PAGE and Western blotting. Protein complexes of 64 kDa, 66 kDa, and 133 kDa were detected. No significant changes in the abundance of these FDecontaining complexes were detected during the reproductive cacle—from proertrns 1500 h to proestrus 2400 h to estrus 1500 h of the rat reproductive cacle (Fig. 2 and data not shown). Similarly proteins of 66 kDa and 133 kDa were detected in homog-enates of the pituitara and were invariant through proestrus and estrus (Fig. 2). To determine whether the FDecontaining complexes were capable of binding activin (free FD rather than bound FD), pituitara blots were incubated with iodin-ated activin and exposed to x-raa film. Neither the 66-kDa nor the 133-kDa proteins were detected ba ligand blotting, indicating that the FD contained in these proteins was fulla occupied (data not shown). birth control yasmin
FIG. 2. Using an FS monoclonal antibody to detect FS and FS-like proteins, 64- to 66-kDa and 133-kDa bands were detected on Western blot (under reducing conditions) in rat ovarian and pituitary homogenates at two representative time points of the estrous cycle.