Influence of luteinizing hormone and prostaglandin F2 alpha on progesterone secretion in superfused bovine luteal tissue slices.

Tissue slices from bovine corpus luteum from Days 12 or 13 of the oestrous cycle were superfused for 8 h, and the progesterone secretion under the influence of prostaglandin F2 alpha (PGF2 alpha) and/or LH was measured. PGF2 alpha at concentrations of 0.28 to 2800 nmol/l medium did not affect the basal progesterone secretion, whereas higher doses (7000 to 28,000 nmol/l) induced a slight increase in hormone secretion. LH, 3.4 nmol/l, caused an increase in the progesterone concentration in superfusates which exceeded the control levels (P less than 0.01). This luteotropic effect of LH was not influenced by simultaneous addition of 28 to 2800 nmol/l PGF2 alpha. PGF2 alpha, 2800 nmol/l, did not inhibit progesterone secretion, when administered together with 0.034 to 34 nmol LH/l. Pre-superfusion with 2800 nmol/l PGF2 alpha had no effect on the LH-stimulated increase in progesterone secretion. It is concluded that in cattle, a direct cellular effect of PGF2 alpha, antagonizing the luteotropic function of LH, may be of less importance than other possible direct and indirect PGF2 alpha actions.