INVESTIGADORES
MIRANDA Leandro Andres
artículos
Título:
Immunocytochemical identification of GTH1 and GTH2 cells during the temperature-sensitive period for sex determination in pejerrey, Odontesthes bonariensis.
Autor/es:
MIRANDA, LEANDRO ANDRES; CARLOS STRUSSMANN,; GUSTAVO SOMOZA,
Revista:
GENERAL AND COMPARATIVE ENDOCRINOLOGY
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Año: 2001 vol. 124 p. 45 - 52
ISSN:
0016-6480
Resumen:
The ontogeny of gonadotropin 1 (GtH1) and 2 (GtH2)
cells and its possible link to gonadal sex differentiation
were studied in pejerrey, Odontesthes bonariensis, by immunocytochemistry
using anti-chum salmonb-GtH1 andOdontesthes bonariensis, by immunocytochemistry
using anti-chum salmonb-GtH1 andb-GtH1 and
b-GtH2 antisera. In adults, GtH1 cells were found in the
proximalis pars distalls (PPD) close to the neurohypophysis,
whereas GtH2 cells were identified surrounding
GtH1 cells, at the external layer of the PPD and in the
pars intermedia. Essentially the same distribution was
observed in larvae. In pejerrey, the phenotypic sex is
governed by the temperature during the critical period of
sex determination (temperature-dependent sex determination,
TSD). Female proportions vary gradually from
100% at 1519° to 0% at 29°, and the critical time of TSD
has been estimated to be 35, 24, and 14 weeks after
hatching at 17, 19, and 27°, respectively. Thus, the expression
of both GtHs was examined weekly in larvae
reared from hatching to week 11, at 17, 24, and 29°. The
proportion of females at 17, 24, and 29° was, 100%, 78%,
and 0%, respectively. Histological ovarian differentiation
was noticed at 7 and 4 weeks at 17 and 24°, whereas
testicular differentiation occurred at 7 and 4 weeks at 24
and 29°. GtH1 cells were first observed at week 3 at 29°
and at week 4 at 17 and 24°. These cells increased in
number until week 4 and then decreased, disappearing
after week 6 at all temperature regimes. GtH2 cells appeared
at week 2 at 24 and 29° and at week 3 at 17°. GtH2
cell number increased until week 3 at 29° and until week
4 at 17 and 24° and then temporarily decreased, thereafter
increasing again. These results strongly suggest that
GtH1 and GtH2 are expressed by different cells. The fact
that GtH1 and GtH2 cells appear just before histological
gonadal differentiation at all temperatures, together with
the peak of GtH1 and GtH2 cell number during the temperature-
sensitive period, suggests that GtHs are related
to sex differentiation or TSD in O. bonariensis.O. bonariensis.
number until week 4 and then decreased, disappearing
after week 6 at all temperature regimes. GtH2 cells appeared
at week 2 at 24 and 29° and at week 3 at 17°. GtH2
cell number increased until week 3 at 29° and until week
4 at 17 and 24° and then temporarily decreased, thereafter
increasing again. These results strongly suggest that
GtH1 and GtH2 are expressed by different cells. The fact
that GtH1 and GtH2 cells appear just before histological
gonadal differentiation at all temperatures, together with
the peak of GtH1 and GtH2 cell number during the temperature-
sensitive period, suggests that GtHs are related
to sex differentiation or TSD in O. bonariensis.-GtH2 antisera. In adults, GtH1 cells were found in the
proximalis pars distalls (PPD) close to the neurohypophysis,
whereas GtH2 cells were identified surrounding
GtH1 cells, at the external layer of the PPD and in the
pars intermedia. Essentially the same distribution was
observed in larvae. In pejerrey, the phenotypic sex is
governed by the temperature during the critical period of
sex determination (temperature-dependent sex determination,
TSD). Female proportions vary gradually from
100% at 1519° to 0% at 29°, and the critical time of TSD
has been estimated to be 35, 24, and 14 weeks after
hatching at 17, 19, and 27°, respectively. Thus, the expression
of both GtHs was examined weekly in larvae
reared from hatching to week 11, at 17, 24, and 29°. The
proportion of females at 17, 24, and 29° was, 100%, 78%,
and 0%, respectively. Histological ovarian differentiation
was noticed at 7 and 4 weeks at 17 and 24°, whereas
testicular differentiation occurred at 7 and 4 weeks at 24
and 29°. GtH1 cells were first observed at week 3 at 29°
and at week 4 at 17 and 24°. These cells increased in
number until week 4 and then decreased, disappearing
after week 6 at all temperature regimes. GtH2 cells appeared
at week 2 at 24 and 29° and at week 3 at 17°. GtH2
cell number increased until week 3 at 29° and until week
4 at 17 and 24° and then temporarily decreased, thereafter
increasing again. These results strongly suggest that
GtH1 and GtH2 are expressed by different cells. The fact
that GtH1 and GtH2 cells appear just before histological
gonadal differentiation at all temperatures, together with
the peak of GtH1 and GtH2 cell number during the temperature-
sensitive period, suggests that GtHs are related
to sex differentiation or TSD in O. bonariensis.O. bonariensis.
number until week 4 and then decreased, disappearing
after week 6 at all temperature regimes. GtH2 cells appeared
at week 2 at 24 and 29° and at week 3 at 17°. GtH2
cell number increased until week 3 at 29° and until week
4 at 17 and 24° and then temporarily decreased, thereafter
increasing again. These results strongly suggest that
GtH1 and GtH2 are expressed by different cells. The fact
that GtH1 and GtH2 cells appear just before histological
gonadal differentiation at all temperatures, together with
the peak of GtH1 and GtH2 cell number during the temperature-
sensitive period, suggests that GtHs are related
to sex differentiation or TSD in O. bonariensis.