Abstract
BackgroundPolycystic ovary syndrome is characterized by hyperactivity of the ovarian sympathetic nervous system, increases in the content and release of norepinephrine, as well as decreases in the number of β-adrenoreceptors. In the present study, β-adrenoreceptors in the ovaries of rats with polycystic ovary syndrome were blocked and analyzed the resultant effects on ovulation, hormone secretion and the enzymes responsible for the synthesis of catecholamines.MethodsAt 60 days of age, vehicle or estradiol valerate-treated rats were injected with propranolol [10− 4 M] into the ovarian bursas on oestrus day. The animals were sacrificed on the next day of oestrus, and the ovulation response, the steroid hormone levels in the serum and the immunoreactivity of tyrosine hydroxylase and dopamine β-hydroxylase in the ovaries were measured.ResultsIn animals with the induction of polycystic ovary syndrome and β-adrenoreceptor blocking, ovulation was restored in more than half of the animals and resulted in decreased hyperandrogenism with respect to the levels observed in the estradiol valerate-treated group. Tyrosine hydroxylase and dopamine β-hydroxylase were present in the theca cells of the growing follicles and the interstitial gland. Injection of propranolol restored the tyrosine hydroxylase and ovarian dopamine β-hydroxylase levels in rats with polycystic ovary syndrome induction.ConclusionsThe results suggest that a single injection into the ovarian bursas of propranolol, a nonselective antagonist of β-adrenoreceptor receptors, decreases the serum testosterone concentration and the formation of ovarian cysts, improving the ovulation rate that accompanies lower levels of tyrosine hydroxylase and dopamine β-hydroxylase in the ovary.
Highlights
Polycystic ovary syndrome is characterized by hyperactivity of the ovarian sympathetic nervous system, increases in the content and release of norepinephrine, as well as decreases in the number of β-adrenoreceptors
We have previously shown that in the cyclic rat the acute blockade of β1 and β2-adrenoreceptors by propranolol injection at different days of the estrous cycle reduced the number of ova shed only in those animal treated on diestrus 2, without affecting ovulation in the other day of the cycle [24]
In a previous study [37] we showed that the elimination of noradrenergic fibers by guanethidine injection before the establishment of Polycystic ovarian syndrome (PCOS) prevents the blockade of ovulation and hyperandrogenism
Summary
Polycystic ovary syndrome is characterized by hyperactivity of the ovarian sympathetic nervous system, increases in the content and release of norepinephrine, as well as decreases in the number of β-adrenoreceptors. Polycystic ovarian syndrome (PCOS) is the most common cause of infertility in women of reproductive age. It has a prevalence between 6 and 10% based on the U.S National Institutes of Health criteria and 15% when the Rotterdam criteria are applied [1, 2]. Fernandois et al [23] showed that the prolonged blockade of β1 and β2-adrenoreceptors in 8- and 10month rats, by i.p. daily injection of propranolol (5 mg/kg of body weight), during 60 days, recovered estrous cyclicity, elevated the ovulation rate, and levels of serum sexual steroids. We have previously shown that in the cyclic rat the acute blockade of β1 and β2-adrenoreceptors by propranolol injection at different days of the estrous cycle reduced the number of ova shed only in those animal treated on diestrus 2, without affecting ovulation in the other day of the cycle [24]
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