Abstract
The effects of the removal of sialic acid from equine chorionic gonadotropin (eCG) (PMSG pregnant mare serum gonadotropin), equine luteinizing hormone (eLH), and equine follicle stimulating hormone (eFSH) are investigated in in vitro bioassays and in radioimmunoassays. The complete removal of sialic acid is carried out by using a highly purified agarose-bound neuraminidase (30-50 U/mg protein). Polyacrylamide disc gel electrophoresis patterns at pH 8.5 show that desialylated preparations are relatively more basic with respect to their native conterparts. The LH activity of desialylated eCG as determined by in vitro steroidogenesis by rat Leydig cells is 5 times greater than that of native eCG, whereas desialylated eLH activity is almost doubled compared with native eLH. In the in vitro FSH bioassay (cAMP production), both desialylated eCG and desialylated eFSH are drastically inactivated. The eCG radioimmunoassay results indicate that both desialylated eLH and eCG are equine but desialylated eFSH shows a fivefold enhancement of immunological activity over native eFSH. The increase of FSH activity on desialylation is also observed in a homologous eFSH radioimmunoassay. These observations suggest that sialic acid plays an important role for the in vitro biological activities of euine gonadotropins and also for the immunological activity of eFSH.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1082-1087 |
| Number of pages | 6 |
| Journal | Biology of reproduction |
| Volume | 24 |
| Issue number | 5 |
| State | Published - 1981 |
ASJC Scopus subject areas
- Cell Biology