The existence of gonadotropin-releasing hormone-like peptides in the neural ganglia and ovary of the abalone, Haliotis asinina L.
Gonadotropin-releasing hormone (GnRH) is a neuropeptide that is conserved in both vertebrate and invertebrate species. In this study, we have demonstrated the presence and distribution of two isoforms of GnRH-like peptides in neural ganglia and ovary of reproductively mature female abalone, Haliotis asinina, using immunohistochemistry. We found significant immunoreactivities (ir) of anti-lamprey(l) GnRH-III and anti-tunicate(t) GnRH, but with variation of labeling intensity by each anti-GnRH type. lGnRH-III-ir was detected in numerous type 1 neurosecretory cells (NS1) throughout the cerebral and pleuropedal ganglia, whereas tGnRH-I-ir was detected in only a few NS1 cells in the dorsal region of cerebral and pleuropedal ganglia. In addition, a small number of type 2 neurosecretory cells (NS2) in cerebral ganglion showed lGnRH-III-ir. Long nerve fibers in the neuropil of ventral regions of the cerebral and pluropedal ganglia showed strong tGnRH-I-ir. In the ovary, lGnRH-III-ir was found primarily in oogonia and stage I oocytes, whereas tGnRH-ir was observed in stage I oocytes and some stage II oocytes. These results indicate that GnRH produced in neural ganglia may act in neural signaling. Alternatively, GnRH may also be synthesized locally in the ovary where it could induce oocyte development.
Nuurai
Parinyaporn
P
Department of Anatomy, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Poljaroen
Jaruwan
J
Tinikul
Yotsawan
Y
Cummins
Scott
S
Sretarugsa
Prapee
P
Hanna
Peter
P
Wanichanon
Chaitip
C
Sobhon
Prasert
P
D000818:Animals; D005260:Female; D017952:Ganglia, Invertebrate / Q000737:chemistry*; D049851:Gastropoda / Q000737:chemistry*; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D007150:Immunohistochemistry; D010053:Ovary / Q000737:chemistry*; D020033:Protein Isoforms / Q000032:analysis / Q000276:immunology; D015398:Signal Transduction
D020033:Protein Isoforms; D007987:Gonadotropin-Releasing Hormone