MIRANDA Leandro Andres
Seasonal changes and endocrine regulation of pejerrey (Odontesthes bonariensis) spermatogenesis in the wild. General and Comparative Endocrinology, 221: 236-243.
ELISIO M; CHALDE T; MIRANDA LA
GENERAL AND COMPARATIVE ENDOCRINOLOGY
ACADEMIC PRESS INC ELSEVIER SCIENCE
Lugar: Amsterdam; Año: 2015 vol. 221 p. 236 - 236
The endocrine mechanisms that regulate spermatogenesis and their interacti on with environmental cues have been poorly studied compared w ith oogenesis in ﬁsh. The aim of this work was to study the sper-matogenesis in pejerrey under the inﬂuence of photoperiod and water temperature ﬂuctuation in the wild, evaluating the transcript leve ls of brain Gnrh variants and cyp19a1b , pituitary Gth subunits, gonadal the receptors, 11b -hsd , and 11-KT plasma levels. Males at spermiogenic stage were observed during spring and autumn, under a photoperiod above 11 h of light and a water temperature below 23 C. Most arrested males were observed in summer when w ater temperatures increased above 23 C. Males at sper-matogon ial stage w ere mainly observed in autumn, while most males at spermatocytary stage were caught in winter. An increase of gnrh-I , cyp19a1b , fshb , gpha and 11 b-hsd transcripts and 11-KT plasma levels was observed during spermatogonial and/or spermatocytary stage (early spermatogenesis). The spermiogenic stag e was associated to the maximum gnrh-I gene expression level and a signiﬁcant increase of Gth receptors transcripts, being this fact more evident for lhcgr . During this last gonadal stage, cyp19a1b transcript level remained high, while fshb mRNA and 11-KT plasma levels showed a signiﬁcant decreased compared to that occurred at the sperma tocytary stage. Also, gpha and 11b -hsd gene expres-sion levels fell during spermiation up to similar values to those observed in arrested males. A signiﬁcant correlation between 11-KT and gnrh-I , cyp19a1b , gph a, fshb , 11 b-hsd transcripts, and the number of sperma tocytes was observed during spermatogenesis. All these ﬁndings suggested that in pejerrey, the sperma tocyte proliferation occurs mainly during winter under the stimulation of 11-KT induced by FSH through the stimulation of speciﬁc enzymes, including the 11b -hsd while spermiation occurs after photoperiod increase and with temperatures of the water below 23 C, through the stimulation of gnrh-I , cyp19a1b and lhcgr.