Identification of immunoreactive FSH and LH cells in the cichlid fish Cichlasoma dimerus during the ontogeny and sexual differentiation

Abstract

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) expressing cells were detected in pituitary, brain and ovary of the Perciform cichlid fish Cichlasoma dimerus. This detection was carried out by immunohistochemistry (IHC) and Western blot techniques using antisera of the Cyprinodontiform Fundulus heteroclitus raised against the conservative region of the teleost betaFSH and the betaLH subunits. The estimated molecular weights were 24 kDa for LH and 19 and 15 kDa for FSH. In the adult pituitary, both cell types were distributed along mid and ventral zones of the proximal pars distalis (PPD, mid-immunoreactive cells), and along the ventral and dorsal external border of the pars intermedia (PI, high-immunoreactive cells). Double IHC showed that FSH and LH are mainly expressed in different pituitary cells. FSH cells were detected in the pituitary around day 21 after hatching (ah) (prior to sex differentiation), while LH cells were detected by day 60 ah (during the sexual differentiation period). A correlation between gonadal sex differentiation and FSH was demonstrated in a 15 days organ culture system. FSH and LH neurons were localized in the nucleus lateralis tuberis and their fibers project through the ventral hypothalamus, preoptic area and neurohypophysis. FSH neurons differentiated on day 21 ah, while LH neurons appeared on day 15 ah. In the ovary, the immunoreactivity for both FSH and LH was restricted to the cytoplasm of previtellogenic and early vitellogenic oocytes.

Examination of the Ability of Gonadal Sex Change in Primary Males of the Diandric Wrasses Halichoeres poecilopterus and Halichoeres tenuispinis: Estrogen Implantation Experiments

“…Immunoreactivities for Fshb and Lhb were localized in separate cells in the pituitary with distinct distributions. These results are similar to those reported for other teleosts [45][46][47][48], with the exception of yellowtail [49] and platyfish [50]. In both sexes of the honeycomb grouper, Lhb cells were numerous and localized widely in the PPD.…”

Presence of β-Follicle-Stimulating Hormone and β-Luteinizing Hormone Transcripts in the Brain of <i>Cichlasoma dimerus</i> (Perciformes: Cichlidae)

“…FSH and LH ir-endocrine cells were detected both in pituitary and brain areas (fig. 2b–f) [for detailed data about GtHs immunolocalization in this species, see [11]].…”

“…PRL, GH, β-FSH, β-LH and SL presence in the pituitary culture media was semiquantified by immunoblots using heterologous antisera, the specificity of which has been previously tested in this species [11,15,16,17] (table 1). Briefly, 16 µl of each pituitary culture medium was separated by electrophoresis on 15% sodium dodecylsulfate-polyacrylamide gel (SDS-PAGE).…”

“…During the study of the C. dimerus pituitary anatomy, ir-FSH and ir-LH fibers were detected in the neurohypophysis (NH) and infundibular stalk [11]. The origins of neurons that project those fibers were cell bodies located in the POA (parvocellular and magnocellular preoptic nuclei) and in the hypothalamus (nucleus lateralis tuberis).…”

“…The origins of neurons that project those fibers were cell bodies located in the POA (parvocellular and magnocellular preoptic nuclei) and in the hypothalamus (nucleus lateralis tuberis). Also, the ontogeny of brain-derived and pituitary-derived GtHs was studied in this species, showing that the timing of appearances of LH and FSH in brain and pituitary were different: LH neurons (day 15), FSH pituitary cells and neurons (day 21) and LH pituitary cells (day 60) [11]. …”