Adenosine facilitates the response to HCG, PGE1 or PGE2 and inhibits the response to PGF2 alpha by HCG-stimulated ovine luteal cells in vitro.

Dispersed ovine luteal cells collected on day 7 or 16 postestrus were incubated in vitro with hCG, PGE1 or PGE2 in the presence or absence of adenosine, dipyridamole (inhibitor of adenosine uptake) or PGF2 alpha in two separate experiments. Secretion of progesterone was increased by hCG, PGE1 or PGE2 when incubated with day 7 luteal cells (P less than or equal to 0.05) which was increased further when co-incubated with adenosine (P less than or equal to 0.05). PGF2 alpha alone or in the presence of hCG decreased (P less than or equal to 0.05) the secretion of progesterone by day 7 luteal cells, PGF2 alpha decreased post treatment cell viability with or without hCG (P less than or equal to 0.05) and adenosine reduced (P less than or equal to 0.05) the inhibitory effect of PGF2 alpha on hCG actions and luteal cell viability. Day 16 luteal cells were not functional based on jugular progesterone (P less than or equal to 0.05) and did not respond to hCG, PGE1, or PGE2 in the presence of adenosine or PGF2 alpha (P greater than or equal to 0.05). It is concluded that adenosine enhances the response of functional luteal cells to the luteotropins hCG, PGE1 or PGE2 and adenosine reduces the luteolytic response to PGF2 alpha by hCG-stimulated ovine luteal cells in vitro.