CONDITIONS MODIFYING THE RELEASE OF SPERMATOZOA IN MALE XENOPUS LÆVIS IN RESPONSE TO CHORIONIC GONADOTROPHIN

¹ University of Edinburgh Pregnancy Diagnosis Laboratory

1. An account is given of the method of obtaining and examining spermatozoa from Xenopus lvis.

2. Speed of response to chorionic gonadotrophin is increased at high temperatures; the ultimate response is little affected.

3. The interval between injection of chorionic gonadotrophin and appearance of sperm is affected by the amount injected.

4. There is no significant difference between response of "gloved" and "ungloved" animals of the same weight with the particular doses employed.

5. Response is roughly proportional to the weight of the toad.

6. Old and new stock imported males respond similarly; laboratorybred Xenopus seem to be less sensitive.

7. Sperm motility and the time Xenopus males remain positive is influenced by dose.

8. Male toads are more sensitive 10 days after previous injection. There is a significant decline in sensitivity from the 15th day onwards. It is suggested that toads for bioassay be used every 10 days.

9. Dose response data are based upon response 4 hrs. and 24 hrs. after injection. Male and female responses to C.G. are compared; their D.R.C. slopes are not significantly different.

10. Spermiation in Xenopus lvis is not specific for C.G. This reaction can be induced by certain steroids, adrenergic drugs and gonadotrophins of the A.L.P., pregnant mares' serum and menopausal urines.

Note:

The author gratefully acknowledges a gift of International Standard chorionic gonadotrophin preparation from the Department of Biological Standards, National Institute for Medical Research. Grateful thanks are also due to Organon Laboratories Ltd. for the generous supply of chorionic gonadotrophin and steroids used in this study.