Luliberin (luteinizing hormone releasing-hormone, LHRH) is the key regulatory decapeptide that controls reproduction in mammals. It is secreted by the hypothalamus and after binding to a specific receptor it initiates a series of events leading to the liberation of lutropin (LH) and finally steroid sex hormones. In some case, the infertility in females and males may be explained by mutations of the LH or LHRH receptor genes. Immunisation of animals with LHRH conjugates induces high titres of antibodies, resulting in the cessation of the biological function of the hormone and, in the end, in a temporary infertility. In this review, the application of LHRH vaccines as birth control for women and men was presented. Being effective and inexpensive, semisynthetic LHRH vaccines are useful in the animal breading for immunocastration,. The best vaccines are totally synthetic LHRH ones, which are much safer than the CG- or LH-vaccines based on antigens isolated from human material, which may be contaminated with pathogens.
Heterodimeric composition and amino acid sequence of hLH is reviewed.The hormone isoforms and methods of their assay are sumarized.Releasing of the hormone, its control by synthetic antagonists and agonists and their sigificance for therapy are described.Structure and function of hLH receptor are presented.
Luliberin ? luteinizing hormone-releasing hormone (LHRH) is the first link in hypothalamus-pituitary-gonads axis which participates in reproduction. This hormone and lutropin are released from immunological cells, however antagonists of LHRH inhibit this action. Some cytokines (IL-1?, GM-CSF) inhibit release of LHRH and other (IL-6, INF-?) stimulate this release.
Luliberyn plays a pivotal role in the reproductive system. Its analogs have wide therapeutic applications ranging form the treatment of some human cancers, gynecological and sexually transmitted diseases to animal breeding. In the article, the development of luliberin agonists and antagonists and the principles of their application were briefly reviewed. Sequences of some important natural and synthetic analogs were presented. Carcinogenic and biodegradation resistable derivatives of luliberin analogs were also described.
Luteinizing hormone (LH) is a heterodimeric glycoprotein containing varied amount of sialic acid. This is a reason of numerous LH isoforms called also isohormones. The hormone isoforms were separated usually by gelelectrophoresis, isoelectrofocusing or chromatofocusing. They differ in biological and immunological activity. Human and some animals LH isoforms were reviewed. Also some genetic mutants of LH are described. Problems of the human isoforms for pathology and diagnostics are presented.
Cyclic GMP is common second messenger in a plethora of processes. Its major intracellular receptors are the cGMP-dependent protein kinases (PKGs). In this minireview we summarise the main results of studies on structure and physiological role of PKGs.
Numerous reports indicate that cyclic 3',5' guanosine monophosphate (cGMP) is involved in the regulation of immune processes. However, the mechanisms responsible for the synthesis of this nucleotide and its signaling pathways in immune cells are still not well recognized. The aim of our study was to establish: 1) which form of guanylyl cyclase synthesizes cGMP in murine lymphoid organs and 2) whether the same organs express the isoforms PKG1alpha and/or PKG1beta of protein kinase G, known as a possible target for synthesized cGMP. Cells isolated from thymus, lymph nodes, and spleen were treated with activators (SNP, ANP, CNP, STa) of soluble or particulate cyclases. Sodium nitroprusside (SNP) elevated intracellular cGMP 2-fold in thymic and lymph node cells and about 10-fold in spleen cells. Atrial natriuretic peptide (ANP) caused modest but statistically significant increases of cGMP in cells of all the organs. Additionally, spleen cells elevated their cGMP content about 2-fold in response to C-type natriuretic protein (CNP). In cellular homogenates of all the analyzed organs, the antibody anti-PKG1beta stained the 78 kDa band corresponding to the molecular mass of PKG1. Only homogenates of spleen cells were stained by the antibody recognizing PKG1alpha. Our results indicate that in all the investigated organs, cGMP may be synthesized mainly by soluble guanylyl cyclases in response to nitric oxide. The modest increase of cGMP upon stimulation by ANP suggests that in all these organs either exist only a small subpopulation of cells that express particulate cyclase GC-A or GC-A is expressed at very low level. In spleen cells, however, cyclase GC-B appears to be the more active enzyme. Elevated cGMP concentration may in turn activate PKG1beta in thymus, lymph node, and spleen cells and also PKG1alpha in spleen cells.
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