Suppression of LH-stimulated prostaglandin and progesterone accumulation in rat granulosa cells by isoquinolinesulfonamide protein kinase inhibitors.

Rat granulosa cells were incubated with isoquinolinesulfonamide inhibitors of protein kinases A and C and/or LH, dibutyryl cAMP (dbcAMP), tetradecanoylphorbol acetate (TPA), cholera toxin, or forskolin for 5 h. H7 (25 microM) was observed to inhibit LH, cholera toxin or dbcAMP stimulation of prostaglandin (PGE), and progesterone accumulation. H7 produced inhibition when added as little as 2 min before and as long as 1 h after LH. HA1004 was ineffective against LH or cholera toxin stimulation of PGE or progesterone at up to 100 microM. H9 blocked some LH and forskolin responses at 25 microM, but required a 50 microM concentration to minimally affect TPA stimulation. Cytotoxicity was not observed at the concentrations and times of isoquinolinesulfonamides tested. H7 and H9, therefore, suppress LH stimulation of granulosa cell functions in a dose- and time-dependent manner consistent with inhibition of protein kinases A and/or C, and consonant with a requirement for such kinases in LH action.