9420328 Lacy The motility of sperm is an extremely important factor in determining successful fertilization in livestock, game animals, and man. Numerous drugs have been used to increase sperm motility but each has a major drawback which includes damage to genetic material, producing defects in the embryo, and instability of the drugs. Dr. Lacy's laboratory has discovered a reproductive gland (alkaline gland) in a cartilagenous fish (the stingray) which produces a fluid that accelerates sperm motility not only in stingrays but also in other fish (bass), bull, and man. Experiments in Dr. Lacy's laboratory further showed that the substance in this fluid which stimulates sperm motility appears to be protein in nature. Antibodies to one particular protein, the hormone relaxin, showed that it is likely to be present in this fluid and may be the causative molecule for increased sperm motility. The objective of the current grant application is to determine the mode of action and physiological significance of alkaline gland fluid protein with attention paid to relaxin. Studies will focus on three specific aims: 1) to isolate and purify the sperm stimulating protein(s); 2) to isolate and identify the molecules on the sperm surface which specifically bind the alkaline gland fluid protein(s); and 3) to determine if stingray relaxin has other effects such as contraction of female uterine smooth muscle which would also aid fertilization. The significance of this study's results will be to elucidate some of the mechanisms for successful fertilization in these fish. ***
