ScienceAsia 32 (2006): 337-343 |doi: 10.2306/scienceasia1513-1874.2006.32.337

Immunocytochemical Identification of Gonadotropic Cell Types and Changes in Cell Numbers during Annual Reproductive Cycle in Pituitary Gland of Adult Male Sand Goby, Oxyeleotris marmoratus

Uraporn Vongvatcharanon^a*, Fardeela Binalee^b, Jintamas Suwanjarat^b and Piyakorn Boonyoung^a

 
ABSTRACT: Pituitary gonadotropes were studied in the adult male sand goby (Oxyeleotris marmoratus) during its annual reproductive cycle. Pituitary glands were taken from each of the 5 stages of testicular development: resting, developing, mature, spawning and spent. The pituitary glands were processed for Masson’s trichrome staining and immunocytochemistry using anti-chum salmon GTH Iβ and GTH IIβ antibodies. Most of the basophils in the proximal par distalis showed immunoreactivity to GTH IIβ. No cell showed immunoreactivity to GTH Iβ at any stage of testicular development. The number of GTH IIβ labeled cells was relatively low in the resting stage (22.46 ± 4.34 cell/mm2) but significantly higher during the developing stage (49.21 ± 7.71 cell/mm2) (P<0.05) compared to the resting stage. The number of immunoreactive cells decreased during the mature stage (31.29 ± 7.23 cell/mm2) and was relatively constant in the spawning stage (30.41 ± 2.56 cell/mm2) and spent stage (29.16 ± 2.21 cell/mm2). Based on the well known function of GTH, the presence of only GTH IIβ but not GTH Iβ in the pituitary gonadotropes suggested the involvement of GTH IIβ in spermatogenesis of the male sand goby. Moreover, the high number of GTH IIβ immunoreactive cells during testicular developing stage correlated with the maturation of sperm further confirmed the role of GTH IIβ in controlling cell proliferation during spermatogenesis.

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^a Department of Anatomy, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand.
^b Department of Biology, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand.

* Corresponding author, E-mail: uraporn.v@psu.ac.th

Received 6 Feb 2006, Accepted 19 May 2006