Action of nitroguanidinated luteinizing hormone on different rat gonadal tissues

• Published in: Molecular and cellular endocrinology Vol. 33; no. 2; pp. 147 - 155
• Main Authors: Tertrin-Clary, C., de la Llosa-Hermier, M.P., Hermier, C., de la Llosa, P.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.12.1983; Elsevier
• Subjects: Adenylyl Cyclases - metabolism; Animals; Biological and medical sciences; Cyclic AMP - metabolism; Female; Fundamental and applied biological sciences. Psychology; Leydig cells; Leydig Cells - drug effects; Luteinizing Hormone - analogs & derivatives; Luteinizing Hormone - antagonists & inhibitors; Luteinizing Hormone - pharmacology; luteinizing hormone derivatives; Male; Mammalian reproduction. General aspects; Ovary - drug effects; Progesterone - biosynthesis; Pseudopregnancy - metabolism; pseudopregnant ovaries; Rats; Rats, Inbred Strains; Sheep; Swine; Testosterone - biosynthesis; Vertebrates: reproduction; luteinizing hormone derivatives; NG; pseudopregnant ovaries; LH; Leydig cells; Pseudopregnancy; Rat; Rodentia; Glycoprotein hormone; Testicle; Male genital system; Biological activity; Leydig cell; Ovary; Vertebrata; Mammalia; Female genital system; Antagonist
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/0303-7207(83)90163-6

The biological activities of nitroguanidinated derivatives prepared from ovine or porcine luteinizing hormone were investigated using rat Leydig cells and pseudopregnant rat ovaries. In these tissues nitroguanidyl ovine luteinizing hormone (NGoLH) or nitroguanidyl porcine luteinizing hormone (NGpLH) were unable to stimulate adenylate cyclase or steroidogenesis but were able to inhibit the binding of ovine or porcine native LH to their specific receptors. When added to incubations of isolated Leydig cells or pseudopregnant ovary slices, NGoLH as well as NGpLH inhibited the stimulating action of native LH on adenylate cyclase or steroidogenesis. However, these derivatives had no inhibiting action on the stimulation of adenylate cyclase and steroidogenesis induced in the Leydig cells by choleratoxin or on the stimulation of testosterone production induced by 8-bromo-cyclic AMP. Since NGpLH (which does not contain lysine residues or free α-amino groups in the β-subunit) exhibits the same antagonist action as NGoLH, we conclude that the nitroguanidination of the α-subunit is sufficient to endow the derivative with antihormone properties.