The effect of 2-bromo-alpha-ergocryptine and 2-chloro-alpha-methylergoline-8beta-acetonitrile (lergotrile mesylate) on the prolactin secretion of the ewe.

The effects of two ergot alkaloids, 2-bromo-alpha-ergocryptine methane-sulphonate (CB154, Sandoz) and lergotrile mesylate (LM, E. Lilly & Co.), on the basal secretion of prolactin and on the prolactin response to TRH or the milking stimulus was investigated in the sheep. Both CB154 (c. 0.5 mg/kg) and LM (c. 0.75 mg/kg) markedly reduced basal levels of prolactin and inhibited the TRH-induced prolactin release in ewes in the mid-luteal phase of the oestrous cycle. Both compounds also suppressed basal levels of prolactin in lactating ewes and inhibited the prolactin response to the milking stimulus in lactating ewes.