Abstract
Increasing evidence in animal models and in humans shows that sympathetic nerve activity
controls ovarian androgen biosynthesis and follicular development. Thus, sympathetic
nerve activity participates in the follicular development and the hyperandrogenism
characteristics of polycystic ovary syndrome, which is the most prevalent ovarian
pathology in women during their reproductive years. In this study, we mimic sympathetic
nerve activity in the rat via “in vivo” stimulation with isoproterenol (ISO), a β-adrenergic
receptor agonist, and test for the development of the polycystic ovary condition.
We also determine whether this effect can be reversed by the administration of propranolol
(PROP), a β-adrenergic receptor antagonist. Rats were treated for 10 days with 125 μg/kg
ISO or with ISO plus 5 mg/kg PROP. The ovaries were examined 1 day or 30 days following
drug treatment. While ISO was present, the ovaries had an increased capacity to secrete
androgens; ISO + PROP reversed this effect on androgen secretory activity. 30 days
after treatment, androstenedione secretion reverted to normal levels, but an increase
in the intra-ovarian nerve growth factor (NGF) concentration and luteinizing hormone
(LH) plasma levels was detected. ISO treatment resulted in follicular development
characterized by an increased number of pre-cystic and cystic ovarian follicles; this
was reversed in the ISO + PROP group. The lack of change in the plasma levels of progesterone,
androstenedione, testosterone, or estradiol and the increased LH plasma levels strongly
suggests a local intra-ovarian effect of ISO indicating that β-adrenergic stimulation
is a definitive component in the rat polycystic ovary condition.
Key words
ovary - β-adrenergic receptor - propranolol
