Recent evidence suggest increased noradrenergic activity in both the anterior hypothalamus and the ovary in PCO. This study was aimed to determine the presence of peripheral catecholaminergic alterations in this syndrome. We studied 14 adolescent PCO patients (mean age 16.9 years) presenting amenorrhea or oligomenorrhea and increased plasma levels of testosterone, androstenedione and LH, and 9 normal cycling controls (mean age 16.7 years). Plasma concentrations of Dopa, norepinephrine, epinephrine, total dopamine and dihydroxyphenylglycol (DHPG) in basal conditions and in response to GnRH were determined by HPLC with electrochemical detection or a radioenzymatic method. Basal urinary Dopa, catecholamines and catechol metabolites: DHPG, vainyllilmandelic acid (VMA), methoxyhidroxyphenylglycol (MHPG), homovanillic acid (HVA), metanephrine (MN) and normetanephrine (NMN) were determined by HPLC with electrochemical detection.

Levels of plasma and urinary Dopa, catecholamines and urinary HVA, VMA, MN and MHPG were similar in patients and controls both in basal conditions and in response to GnRH. PCO patients had significantly lower levels of plasma DHPG(712 ± 45 vs 1364 ± 178 pg/ml; p<0.01), urinary DHPG (78± 4 vs 124 ± 15 μg/24 hs, p<0.01) and significantly higher urinary excretion of NMN (213 ± 23 vs 147 ± 19 μg/24hs; p<0.05) than controls.

These results show clear peripheral catecholaminergic alterations in PCO patients. The decreased plasma DHPG levels suggest decreased neuronal norepinephrine reuptake (uptake 1). This suggestion is further supported by the increased urinary NMN levels reflecting increased extraneuronal metabolism of norepinephrine.