April - June 2006, Volume 2, Issue 2

Ianas O, Manda D, Dinu Draganescu D, Calarasu R, Busu C, Vladoiu S

Circadian changes of melatonin secretion in male idiopathic infertility

Acta Endo (Buc) 2006, 2 (2): 129-138
doi: 10.4183/aeb.2006.129

Objective: The goal of this research is to investigate whether melatonin, a circadian informant, is implicated in idiopathic oligospermia in men.\r\nSubjects and methods: 12 men (mean age 30.5 yr) with normal sexual function diagnosed with idiopathic oligospermia and 8 healthy men were included. In urine 6-sulfatoxymelatonin (aMT6s), a reliable index of melatonin secretion and gonadotropins, LH and FSH were assayed. In plasma LH, FSH, DHEA-S, 17-OH progesterone, testosterone, free testosterone, SHBG were measured at 08:00.\r\nResults: As expected, in the infertile group reproductive hormones were within normal limits but persisted low testosterone and high gonadotropins. Estimated bioavailable testosterone also showed a significant decrease (p=0.03). Evaluation of individual differences in circadian production of both melatonin and gonadotropins exhibited substantial changes in their secretion pattern from the phase shifts to loss of rhythm for aMT6s. The reduced amplitudes (p=0.04) of aMT6s were associated with a longer duration of melatonin secretion (p< 0.001) as estimated from onset/offset time and a reduced ratio between night- and daytime; the mean 24h amount of aMT6s tended to decrease at significant limit (p=0.05); no significant correlation between aMT6s and gonadotropins was observed compared with the control group. The amplitudes of gonadotropins were lower while their mean 24 h amount showed a moderate increase.\r\nConclusions: The present findings suggest that the significant increase in the duration of melatonin secretion may contribute to the imbalance of reproductive hormones that affect spermatogenesis; aMT6s, urinary metabolite of melatonin may be a sensitive predictor in circadian disorders of reproductive axis.

Keywords: melatonin, 6-sulfatoxymelatonin, idiopathic infertility, circadian rhythm

Correspondence: Olga Ianas, &#8220;C.I. Parhon&#8221; Institute of Endocrinology, Bd. Aviatorilor 34-36 011863, Bucharest, Romania Tel: +4021.317.20.41 Fax: +4021.317. 64.95 E-mail: oianas@yahoo.com