Golden Hamster Eggs Research Articles

Induction of zona reaction in golden hamster eggs by cortical granule material.

BRADEN et al.1 have shown that the zona pellucida of mammalian eggs changes after fertilization so that penetration of further spermatozoa is greatly reduced. Austin and Braden2 inferred that this zona reaction was due to the action of the cortical granule material which is released from the egg into the perivitelline space shortly after sperm entry into the egg cytoplasm. We wish to present experimental evidence to support this inference.

In vitro fertilization of mouse eggs in the presence of bovine follicular fluid.

SINCE the recognition of “capacitation of sperm” in the female tract1,2, fertilization in vitro of eggs has been successfully conducted by insemination of sperm recovered from the uterus for the rabbit3,4, hamster5 and mouse6. Successful fertilization of golden hamster eggs in vitro by epididymal (uncapacitated) hamster sperm5, in the presence of follicular fluid of hamster7 or cow8, or in the presence of rabbit tubal cyst fluid (our unpublished work), and that of Chinese hamster eggs in the presence of follicular fluid of golden hamster9, encouraged us to carry out the following experiment which demonstrated that mouse sperm can be capacitated in vitro to fertilize mouse eggs in the presence of bovine follicular fluid.

On DPNH-diaphorase and alkaline phosphatase in the preimplantation stages of golden hamsters (Mesocricetus auratus Waterh.)

The activity of the DPNH-diaphorase and the alkaline phosphatase were examined in golden-hamster eggs prior to fixation. The reactions for DPNH-diaphorase as well as for alkaline phosphatase were found to be positive already in the undivided egg and in early cleavage stages. The reaction products of both enzyme determinations showed a histophotometrically measurable polar distribution in the cytoplasm, in the one-cell stage as well as in the individual blastomeres of the examined early cleavage stages.

Role of the rodent acrosome and perforatorium in fertilization.

A study has been made of the morphology of spermatozoa recovered from the female genital tract shortly after coitus, including spermatozoa entering and within eggs, in five rodent species. Elevation and loss of the acrosome was observed to occur in actively motile golden-hamster spermatozoa found in the cumulus oophorus and tubal fluid. Motile spermatozoa lacking the acrosome were also seen in the tubal fluid in guinea-pigs, in the cumulus oophorus in the guinea-pig and Libyan jird, and in the zona pellucida or perivitelline space of guinea-pig, golden-hamster, Chinese-hamster and jird eggs. It is concluded that the acrosome becomes modified in spermatozoa passing through the female genital tract and is detached before the spermatozoon penetrates the zona pellucida. These changes in the acrosome are considered to constitute ‘capacitation’. Removal of the acrosome exposes the perforatorium, which may carry a lysin capable of altering the zona substance in such a way as to permit the spermatozoon to pass through into the perivitelline space. The function of the acrosome is thought most likely to be the carriage of hyaluronidase, which probably enables the spermatozoon to pass through the cumulus oophorus. The separation of the nucleus from the perforatorium was observed in the vitellus of rat and golden-hamster eggs.