Sensitivity to maturation-inducing steroids and gonadotropin in the oocytes of blue gourami Trichogaster trichopterus (Anabantidae, Pallas, 1770).
This study examined in vitro the effect of 17 alpha-hydroxyprogesterone (17-P), 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20-P), and human chorionic gonadotropin (hCG) on vitellogenesis and the induction of germinal vesicle breakdown (GVBD) in oocytes of the female Trichogaster trichopterus (Pallas, 1770) after various in vivo treatments: (a) in nonreproductive condition; (b) in reproductive condition together with males; (c) injected with hCG; (d) injected with extract of carp gonadotropin (cGtH). Neither 17-P nor 17,20-P affected vitellogenesis or GVBD in oocytes from females in nonreproductive condition. However, the development of maturational competence was observed in oocytes obtained from fish in the other three treatments, 17,20-P having a significantly higher effect than 17-P. In vivo injection with hCG raised the percentage of vitellogenesis and caused some GVBD, while the addition of 17-P or 17,20-P in vitro significantly increased GVBD. Similarly, females maintained with males for 48 hr showed GVBD in all the in vitro cultures treated with 17,20-P. Injection in vivo with cGtH caused sensitivity to both 17,20-P and hCG treatment in vitro, leading to ovulation. It may be concluded that, since injection with hCG and cGtH, like the presence of the male, leads to maturational competence in the female, male presence causes the secretion of these maturation-inducing hormones.
Degani
G
G
Migal-Galilee Technological Center, Kiryat Shmona, Israel.
Boker
R
R
D019326:17-alpha-Hydroxyprogesterone; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005399:Fishes / Q000502:physiology*; D006908:Hydroxyprogesterones / Q000494:pharmacology*; D066298:In Vitro Techniques; D009865:Oocytes / Q000187:drug effects*; D009866:Oogenesis / Q000187:drug effects; D012741:Sexual Maturation / Q000187:drug effects; D014818:Vitellogenesis / Q000187:drug effects
D006063:Chorionic Gonadotropin; D006908:Hydroxyprogesterones; C007433:17,20-dihydroxy-4-pregnen-3-one; D019326:17-alpha-Hydroxyprogesterone