[The intragonadic cybernins (author's transl)].
The testis and the ovary produce peptidic substances acting at the gonad level to regulate several reproductive functions. They may be called cybernins. Some of them are well identified. Thus, granulosa cells secrete into follicular fluid an oocyte maturation inhibitor (OMI) which inhibits the meiosis resumption until preovulatory LH peak. Follicular fluid also contains A FSH receptor binding inhibitor (FSH RBI) which seems to be implied in maintaining the follicles at immature stages or in leading them to atresia. FSH RBI is also found in testis extract. Luteinization inhibitor (LI) probably acts to keep granulosa cells from luteinization prematurely and inhibits progesterone secretion. Inhibin is produced by Sertoli cells in male and by granulosa cells in female. It inhibits FSH synthesis and secretion by the pituitary cells via a classical feedback mechanism. Furthermore, it directly decreases spermatogonial mitosis and progesterone secretion by granulosa cells as demonstrated by "in vitro" experiments. LH receptor binding inhibitor (LH RBI)is found in corpus luteum. As the corpus luzeum ages, it contains more of LH RBI. This cybernin which reduces progesterone secretion by granulosa and luteal cells is a possible factor involved in luteolysis. Gonadocrinins, produced by the ovary and the testis, release gonadotrophins from pituitary cells like hypothalamic LH-RH. They also bind to specific receptors on Leydig and Thequa Interna cells inducing a reduction of prolactin and LH receptor number. Steroidogenesis and gametogenesis are thus impaired. Biochemical structures of these cybernins are still unknown as their physiological and biochemical interrelationships.
D003338:Corpus Luteum / Q000187:drug effects; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors* / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology; D006727:Hormone Antagonists / Q000502:physiology*; D006801:Humans; D007265:Inhibins; D036341:Intercellular Signaling Peptides and Proteins; D007986:Luteinizing Hormone / Q000037:antagonists & inhibitors; D008297:Male; D009865:Oocytes / Q000187:drug effects; D006080:Ovarian Follicle / Q000187:drug effects; D010053:Ovary / Q000502:physiology*; D010455:Peptides / Q000502:physiology*; D011506:Proteins / Q000502:physiology; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000502:physiology; D013735:Testicular Hormones / Q000502:physiology; D013737:Testis / Q000502:physiology*
D006727:Hormone Antagonists; D036341:Intercellular Signaling Peptides and Proteins; C011898:LH receptor binding inhibitor; D010455:Peptides; D011506:Proteins; D011956:Receptors, Cell Surface; D013735:Testicular Hormones; C018355:intraovarian peptides; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
Les cybernines intragonadiques.