Changes in Pituitary LH Concentration during Pseudopregnancy in the Rat.

Abstract

Summary The LH concentration (measured by the ovarian ascorbic acid depletion assay) in the pituitaries of pseudopregnant rats showed a fairly progressive rise from day 1 of the diestrus through day 11. On day 1? the level (2.0 μg/nig dry wt) was equivalent to that seen in cyclic rats in estrus or on day 1 of diestrus. The levels virtually equalled or slightly exceeded those characteristic of proestrus (4.2 μg/mg dry wt) from day 4 through 8. On days 9 through 11, the mean potency (5.4 μg/mg dry wt) somewhat exceeded proestrous levels. On day 12 the LH concentrations (l.5 to 2.0 μg/mg dry wt) were again typical of estrous levels in cyclic rats.