D. Loutradis et al., THE EFFECT OF COMPOUNDS ALTERING THE CAMP LEVEL ON REVERSING THE 2-CELL BLOCK INDUCED BY HYPOXANTHINE IN MOUSE EMBRYOS IN-VITRO, European journal of obstetrics, gynecology, and reproductive biology, 57(3), 1994, pp. 195-199
The possibility of reversing the hypoxanthine induced 2-cell block in
mouse embryos when cultured in conditions supplemented with compounds
that increase (FSH, hMG, IBMX, hCG) or inhibit (GnRH-analogue) cAMP wa
s assessed. When embryos were cultured in Ham's F-10 without hypoxanth
ine supplemented with each of the above compounds, no inhibition of bl
astocyst development was observed. Embryos were then cultured in Ham's
F-10 with hypoxanthine supplemented again with each compound. For the
addition of GnRH-analogue or FSH, the rate bf blastocyst formation wa
s comparable with that of the control medium with hypoxanthine alone.
Instead, the addition of IBMX or hMG reversed the induced block. There
was no reversible effect for the addition of 2 mu g/ml hCG while the
latter was observed with higher doses. The results from GnRH-analogue
and IBMX addition show that, contrary to what was found for oocytes, s
timulation of cAMP reverses the hypoxanthine-induced block in mouse em
bryos. FSH and hCG also had effects opposite to those observed for ooc
ytes. It is unknown why hMG (FSH + LH) reverses the block, A lower cAM
P degradation rate resulting in a higher cAMP level is a possible expl
anation. Our results provide further evidence that cleavage arrest by
hypoxanthine has a different mechanism than the hypoxanthine-induced a
rrest of meiosis.