The effect of luteinizing hormone on parturition in rats; imidazole antifungals may affect parturition via luteinizing hormone.

Studies were carried out to investigate the mechanism whereby the imidazole anti-fungal, tioconazole, affects parturition in rats. Administration s.c. of luteinizing hormone (LH) to pregnant rats on days 15-17 post-insemination (p.i.) or days 15-21 p.i. delayed the onset of parturition by a day and markedly reduced the ovarian production of 17 beta-estradiol, but not of progesterone. Administration of LH on days 18 and 19 p.i., which was already known to advance birth, reduced ovarian production of progesterone, but not of 17 beta-estradiol. The similarity of these results to those for tioconazole administered from days 15 p.i. or on days 18 and 19 p.i. suggests that tioconazole affects parturition in rats, at least in part, via LH.