Luteinizing hormone pulse frequency and amplitude in azoospermic, oligozoospermic and normal fertile men in Turkey

Ö Odabas¹, M. K. Atilla², Y. Yilmaz², M. R. Sekeroglu³, E. Sengl², S. Aydin²

¹Fifth Urology Clinic of Van State Hospital, ²Department of Urology, ³Department of Biochemistry, Medical School of Yznc Yil University, Van Turkey

Asian J Androl  2002 Jun; 4:  156-158             

Keywords: luteinizing hormone; pulse frequency; pulse amplitude

Abstract

Aim: To investigate the LH pulse frequency and amplitude in azoospermic and oligozoospermic patients and to compare them with normal fertile subjects. Methods: In this controlled clinical study, 10 normal fertile male volunteers and 20 infertile patients (10 oligozoospermic and 10 azoospermic) were enrolled. Blood samples were taken every 30 minutes for 12 hours. FSH, LH and T levels were determined. LH was observed at all the blood samples, but FSH and testosterone only at the first, middle and last samples. Results: The mean LH levels were significantly different between all the groups, but there was no statistical difference in the FSH levels between the fertile and oligozoospermic groups. The mean LH levels increased from the fertile towards the azoospermic groups (P<0.01). The LH pulse amplitude and frequency were significantly different between all the 3 groups. The former increased while the latter decreased from the fertile to the azoospermic groups. The T levels were different statistically only between the fertile and the azoospermic groups. Conclusion: The more prominent is the testicular defect, the lower will be the LH pulse frequency and the higher the amplitude.

1 Introduction

GnRH is released episodically into the hypophyseal portal system and stimulates the pulsatile secretion of LH and FSH, which in turn regulate gonadal function. The apparent frequency of pulsatile immunoreactive LH release is approximately one pulse every 60 to 180 minutes [1-3]. From a practical standpoint since gonadotropins regulate gonadal hormones, pulsatile LH secretion is accepted as a good index of GnRH release [4,5] and LH pulse determinations in the peripheral blood is an important aspect and give some clues to disorders of hormonal regulation. The present study was designed to investigate the LH pulse frequency and amplitude in infertile and normal men in Turkey in order to compare their interrelationship.

2 Materials and methods

2.1 Subjects

Twenty male infertile patients (10 oligozoospsermic and 10 azoospermic), aged 24-39, were recruited together with 10 normal men of the same age range. The mean ages were 332.8 , 343.8 and 343.5 in the azoospermic, oligozoospermic and fertile groups, respectively. All men in the three groups were married and the infertile patients had a history of infertility for more than one year. Informed consent was obtained from all the subjects. Azoospermic cases were chosen from the patients with normal or nearly normal testicular size. All subjects had at least two sperm analysis. Sperm count less than 20 million/mL was regarded as oligozoospermia. Azoospermia was defined as absence of spermatozoa in centrifuged semen sample in 10 low power microscopic fields.

Blood samples were obtained every 30 minutes beginning from 08:00 to 20:00, with a toal of 25 samples for each subject. LH were assayed in all of the samples and FSH and testosterone in the first, the middle and the last samples. Gonadotropins and testosterone were measured using Immulite Automated Analyzer and commercial kits ( DPC-Diagnostic Products Corporation, Los Angeles, USA).

The LH pulse amplitude was the LH peak level minus the mean level. The pulse frequency was the number of LH peaks in the 12 hours sampling period.

Data were experssed in meanSD. One way Analysis of Variance (ANOVA) was used for statistical analysis and P<0.05 set as significant.

In oligozoospermic patients, the sperm count in the ejaculate was 8-20 (mean 13.5) million/mL with a 10-50% motility. The fertile subjects had sperm counts of 25-80 (mean 51.9) million/mL.

Histopatologic examinations of the testicular specimens from azoospermic patients revealed severe hypo-spermatogenesis in 4 and Sertoli-cell-only in 6 patients.

The azoospermic group had the lowest LH pulse frequency and the highest pulse amplitude. The oligo-zoospermic group had a higher LH pulse frequency and a lower pulse amplitude than the azoospermic group. The fertile group had the most frequent LH pulse and the lowest pulse amplitude. The differences between LH pulse amplitude and pulse frequency of the three groups were statistically significant (P<0.01, F=34.44 and F= 43.65 respectively). Table 1 shows the LH pulse frequency and LH pulse amplitude for all the groups. One can see that the peak pulse levels were the highest in the azoospermic group and the lowest in the fertile group.

Table 1. LH pulse frequency and pulse amplitude (meanSD). ^cP< 0.01.

The FSH levels were statistically different between the azoospermic group and the other two groups (P<0.01, F=17.84). But the difference between the fertile and the oligozoospermic groups was insignificant (Post Hoc. Comparison with Student Newman Keuls test). Its level increased gradually from the fertile towards the azoosper-mic groups. The mean FSH, LH and testosterone levels are shown in Table 2. The LH levels were different between all the groups (P<0.01, F=65.62), while the T levels were different only between the fertile and the azoospermic groups (P<0.05).

Table 2. Mean LH , FSH and T levels (meanSD). ^bP< 0.05, ^cP< 0.01.

There is much controversy about the hormonal and the LH pulse frequency and amplitude changes in male idiopathic infertility. Gross et al. [6] reported that, the LH pulse frequency was low in the oligozoospermic men with elevated FSH when compared with normal men. They did not find any significant changes in serum LH amplitude and testosterone levels. Other authors also reported a decrease in the LH pulse frequency with elevated FSH in infertile men [7-9]. However, Wu et al [10] did not think that the LH pulse frequency was decreased in the infertile men. Bennet et al. [11] and Booth et al. [12] reported an increased LH pulse frequency with or without FSH elevation in oligozoospermic patients. Winter et al. [13] indicated that in primary testicular defect, the LH pulse frequency and amplitude were increased. Chavarria et al. [14] suggested a significant diminition in the amplitude and frequency of LH pulse in the infertile patients.

The decrease in LH pulse frequency in infertile groups observed in the present study are similar with many previous studies [3-6]. However only Winter [13] reported an increase in the LH pulse amplitudes similar to our data. On the other hand, he found an increase in the LH pulse frequency which is not in consistent with our results. The differences in the results obtained in various studies may be due to the heterogeneity of the patients and their primary pathology. However, there seems to be an interrelationship between the LH pulse amplitudes and gonadotropin levels. The more is the gonadotropin level, the more will be the LH pulse amplitude and the less will be the LH frequency.

Since receptors for androgens and FSH are confined to the somatic cells of the testis, the trophic effects of these hormones on germ cell must be indirect. It is not known which genes/factors mediate the beneficial effects of androgens and FSH on spermatogenesis. The gonadotropic hormones have been found in a number of isoforms and multiple transcripts of the LH and FSH receptor have been detected.Therefore, the possibility must be considered that certain forms of male infertility could be due to hormone dysfunction and/or mutated receptors [15].

Some investigators indicated that the FSH increased and the LH and testosterone remained unchanged in approximately 20 % of oligozoospermic patients [16]. Several authors proposed that GnRH stimulation was capable of regulating FSH and LH levels differentially [6, 8, 9,17], which might be the cause of isolated FSH elevation in certain cases. In our study we did not find any isolated FSH increase. The mean LH amplitude was higher in oligozoospermic patients than in normospermic, but lower than in azoospermic patients. It seems that the LH amplitude increased parallel to the severity of the disorder.

References

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Correspondence to: Dr. Öner Odabas, Van Devlet Hastanesi, Üroloji Uzmani, Van Turkey.
Fax: +90-432-216 7519
email: onerodabas1@ixir.com or onerodabas@hotmail.com
Received 2001-06-10      Accepted 2002-05-12