ESTUDIO CINETICO DE LA PULSATILIDAD DE LA SECRECION DE GONADOTROFINAS Y TESTOSTERONA EN VARONES EUSPERMICOS FERTILES E INFERTILES CON OLIGOASTENOZOOSPERMIA IDIOPATICA

Idiopathic oligoasthenozoospermia is among the most frequent causes of male infertility and has a not very well understood etiopathogenia. To obtain valuable information about the role of some endocrine factors in the etiology of this kind of infertility, information that is not easy obtain by the traditional analytical methods, we applied some recently proposed mathematical algorithms to analyze with more exactitude the importance of the secretory pulses of three hormones, luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (T). Serum samples were obtained every 10 min for 12 h, from 15 fertile euspermic men and 14 infertile patients with idiopathic oligoasthezoospermia; the concentration profiles of FSH and T were analyzed by IRMA and RIA, and the immune-and bioactive LH concentrations were quantified by IRMA and bioassay. To assess the pituitary stores of LH and FSH, after 8 h of spontaneous secretion we administered (2 h apart) 2 intravenous pulses containing 10 μg of a GnRH analog, and the sampling continued as described. Hormonal pulsatility was assessed by a computerized cluster analysis method and by the multiple parameters deconvolution method. In the infertile patients we found a significant diminution in the length and frequency of LH pulses, compared with the euspermic men. However, LH half life, the interpulse interval, the amplitude and the mass secreted per pulse rised in the infertile males compared with the controls. The increase in the LH half life suggests the secretion of a more acidic isoform of this hormone in the infertile group. After the GnRH injection the LH secreted mass and mean concentration rised significantly in both groups; this effect was higher in the infertile oligoasthenozoospermic men. In this group we also found a decrease in the bioactive LH interpulse interval and therefore more pulses during the sampling interval, that produced a higher concentration of this kind of hormone in these patients. Oligoathenozoospermic men secreted approximately 70% more bioactive LH as a response to the first GnRH injection than the normal controls. The desensitization observed with immunoactive LH (diminution in the mass secreted after the second GnRH bolus compared with the first one) was also observed with bioactive LH. In the infertile men group we found a significant reduction in the FSH halflife compared with the euspermic controls; this fact suggests that, contrarily to the results observed with LH, a more basic isoform is secreted in these patients. Besides, the mass secreted per FSH pulse was higher, as well as the secretion rate that reached values 3 times higher in the infertile males. Nevertheless the smaller half life of this hormone, its mean concentration was higher too. This suggests that oligoasthenozoospermia is accompanied by FSH sobresecretion in the basal state; however, we did not find difference in the FSH pulses frequency. After the administration of GnRH we observed a 6-7 times increase in the secreted FSH mass in both studied groups. FSH secretion was always higher after the first than after the second GnRH pulse, which indicates desensitization or exhaustion of the releasable FSH stores. In the oligoasthenozoospermic males group, testosterone showed a significant diminution in the pulses frequency, but all other parameters related to testosterone secretion were not different between both groups under study. Differences observed in the infertile patients in the secretion patterns of FSH, as well as immunoactive and bioactive LH, reflect alterations in the hypothalamus-pituitary axis functions in the hypothalamus-pituitary axis function that can be related to the diminution in spermatozoa production, characteristic of this kind of pathology.