Protein neosynthesis by porcine oocytes matured in vivo and in vitro.

The protein pattern of individual porcine oocytes matured as intact cumulus oocyte complexes either in vivo or in vitro with or without FSH and LH for 43 h were investigated. The synthesis of a 53 kDa polypeptide ceased 21 h after hCG administration wheras a 44 kDa polypeptide were consistently absent in the protein patterns of nearly all of the in vivo maturing oocytes. Furtheron, a polypeptide with a relative molecular weight of 46000 persisted throughout maturation. A precipitous increase in the synthesis of two other proteins with relative molecular weights of 38000 and 28000, respectively, was observed at 9 and 21 h after hCG injection. In in vitro matured oocytes with or without FSH and LH the synthesis of the 53 kDa band decreased after a culture period of 9 h. Furtheron, the production of the 44 kDa polypeptide ceased only in oocytes incubated in FSH and U-l supplemented media after 21 h of culture. On the other hand, the two proteins of Mr 38000 and 28000 appeared only in most of the protein profiles of oocytes cultured with FSH and LH for 43 h. The production of the 46 kDa polypeptide during a 21 h culture period was significantly affected by the presence of additional granulosa cells in connection with the cumulus oocyte complex. Neither the appearance nor the disappearance of the 5 investigated bands was influenced by the presence or absence of the germinal vesicle after 21 h of culture. It is concluded that at least the addition of FSH and LH to the culture medium is necessary for cumulus oocytes complexes to synthesize a protein pattern closely corresponding to that produced by in vivo matured oocytes.