Mating Interval Research Articles

Dominant lethal mutations in male mice

Dominant lethal mutations are due to chromosome aberrations as demonstrated by analysis of first cleavage. With a sample size of 40-45 mice per dose the induction of dominant lethal mutations by 10 mg/kg of methyl methanesulfonat (MMS) can be detected in spermatids in the mating interval 9-12 days posttreatment (6-11%). In the same mating interval a dose of 150 mg/kg of MMS induces 100% dominant lethal mutations. MMS and other chemical mutagens can be characterized by their different spermatogenic response. The germ cell stage specific induction of dominant lethal mutations by chemical agents is very likely due to their different pathways and therefore, to different effects on the structural and macromolecular changes during spermatogenesis. The feasibility of standardizing test protocol for the dominant lethal assay in mice, based on collaborative studies, is discussed. The reproducibility of results and the sensitivity of the induction of dominant lethal mutations in the collaborative studies demonstrate the usefullness of the method for mutagenicity screening.

Sexual exhaustion and recovery of masculine copulatory behavior in virilized female rats

In 1942 Beach and Rasquin concluded that the female rat possesses the neuromotor organization necessary for the execution of masculine copulatory behavior. This conclusion was based on observations of male-type mounting behavior, by intact and ovariectomized female rats. These responses consisted of mounts without pelvic thrusting, mounts with pelvic thrusting, and mounts with thrusting plus the intromission reflex, a deep vigorous thrust followed by a rapid withdrawal from the stimulus female. Exogenous testosterone treatment increases the total mount frequency and the probability of intromission (Beach, 1942). In the male rat the intromission reflex normally occurs when the penis is inserted into the vagina. In these early studies the occurrence of the male's characteristic ejaculation reflex was not observed. The present report describes the frequency and timing of male-type copulatory responses, including the ejacula­ tion reflex in female rats which were genitally masculinized by pre- and early post-natal stimulation by testosterone. When the male is placed with a receptive female he will execute a series of mounts with pelvic thrusting, most of these resulting in intromission. Following a series of mounts with intromission, the ejaculation reflex will occur, the first ejaculation occurring after approximately II intromissions. Following ejaculation a non­ mating interval of approximately 5 min will occur before mating resumes. The second ejaculation will occur after fewer intro­ missions (6-7) and the second post-ejaculatory interval will be longer than the first. Normally the male will achieve 6-7 ejacuaition responses before mating ceases (Beach & Jordan, 1956). Following such a sexual exhaustion test the male rat is unlikely to mate 24 h later. If the male is tested four days after exhaustion, mating will occur but the exhaustion criterion will be reached after fewer intromissions and ejaculations than were displayed on the initial test. After two weeks without mating, the male rat will again display 6-7 ejaculations and approximately 35-40 intro

RELATION OF THE MATING INTERVAL TO THE OCCURRENCE OF SUPERFETATION IN THE MINK

Acta ZoologicaVolume 32, Issue 3 p. 255-258 RELATION OF THE MATING INTERVAL TO THE OCCURRENCE OF SUPERFETATION IN THE MINK IVAR JOHANSSON, IVAR JOHANSSON Institute of Animal Breeding. Royal Agricultural College of SwedenSearch for more papers by this authorOLE VENGE, OLE VENGE Institute of Animal Breeding. Royal Agricultural College of SwedenSearch for more papers by this author IVAR JOHANSSON, IVAR JOHANSSON Institute of Animal Breeding. Royal Agricultural College of SwedenSearch for more papers by this authorOLE VENGE, OLE VENGE Institute of Animal Breeding. Royal Agricultural College of SwedenSearch for more papers by this author First published: September 1951 https://doi.org/10.1111/j.1463-6395.1951.tb00469.xCitations: 12AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume32, Issue3September 1951Pages 255-258 RelatedInformation