Luteinizing hormone (LH) is produced by the anterior pituitary gland and acts to stimulate steroid production by the gonads of both males and females. Among the hormones known to exist, LH has one of the more complex chemical structures because it contains two dissimilar peptide chains and because each of these peptide chains has attached sugars. During the synthesis of this hormone, some of the sugar portions of the molecules are altered giving them different amounts of molecular charge. Thus, rather than existing as a single molecular entity, luteinizing hormone exists as a family of closely related molecular forms. Previous research has demonstrated that the distribution of LH among these identifiable molecular forms can be changed by hypothalamic and gonadal hormones which act at the anterior pituitary gland to regulate the secretion of luteinizing hormone. Research to be performed will address the major question: "Does the fact that luteinizing hormone exists as a family of identifiable molecular components play a significant role in regulating the reproductive processes of animals?" In order to answer this question, sheep will be used as the experimental model because they have relatively large pituitry glands from which these distinct molecular forms can be purified. Once these are purified, their chemical structures will be obtained. In addition, the biological functions of selected molecular forms of luteinizing hormone will be examined by determining their ability to survive into circulation,by examining their ability to stimulate gonadal target cells in vitro and by examining their ability to stimulate gonadal target cells in intact animals. This research should reveal whether the subtle changes which occur in the molecular structure of ovine LH play a significant and meaningful role in the regulation of reproductive function.//
