Ageing of the female gamete. 2 Lactate dehydrogenase activity in fragmented oocytes and ova of the rat.

LDH enzyme activities were determined in atretic and fragmented oocytes. The enzymatic activities in fragmented oocytes and ova were compared to those already known in early rat cleavage stages. Atretic oocytes are totally devoid of LDH activity. However, fragmented oocytes and ova exhibit nearly identical LDH activities to early cleavage stages. This result supports our earlier assumption that fragmentation and cleavage are homologus processes, induced by the same maternally transmitted factors in the oocyte cytoplasm.