Germinal vesicle breakdown in oocytes of catfish, Mystus vittatus (Bloch): in vitro effectiveness of mammalian pituitary hormones.

The effect of six mammalian pituitary hormones on germinal vesicle breakdown (GVBD) in Mystus vittatus oocytes was investigated in vitro. bLH was found to be most effective at the concentration of 10 micrograms/ml of incubation medium, causing GVBD in 68.4 +/- 1.2% oocytes (P less than 0.001). It could also induce GVBD at the concentrations of 1.0 micrograms/ml (P less than 0.001) and 0.1 micrograms/ml (P less than 0.005). Among other hormones, oFSH could cause GVBD in 16.6 +/- 2.8 and 9.7 +/- 1.0% oocytes at the concentrations of 10 and 1.0 microgram/ml, respectively (P less than 0.05). However, bTSH, bGH, oPRL, and hACTH (synthetic) had no effect on GVBD in the oocytes of this species.