Circadian patterns of plasma melatonin, FSH, LH, prolactin, and testosterone were studied in 10 healthy men, 20 men with oligozoospermia, and 8 men with azoospermia. Circadian rhythms were found in concentrations of melatonin and prolactin, with higher values at night in comparison with daytime levels. In patients with oligozoospermia and azoospermia an elevation in melatonin levels was observed, and an increase in melatonin concentrations occurred before onset of darkness (i.e., at 2000 h). Levels of FSH, LH, and prolactin were elevated in infertile patients. The possibilities that an increase in melatonin concentrations is either the primary feature that leads to the regression of the seminiferous epithelium or is secondary and depends on elevated gonadotropins and/or prolactin levels are discussed.

Several data suggest that the endocrine and immune systems are closely interconnected, therefore, we investigated the effect of interleukin-1 on adrenocortical regeneration. The study was performed on adult rats subjected to left adrenal enucleation combined with contralateral adrenalectomy. The animals were given purified human recombinant IL-1 alpha (5 micrograms/kg), IL-1 beta (5 micrograms/kg) anti-human IL-1 receptor antibody (10 micrograms/kg) and combination of interleukins and antibodies. The cell proliferation measured by bromodeoxyuridine incorporation and plasma corticosterone determined by a RIA kit were evaluated six days after operation. The mean cell growth ratio expressed as number of BrdU-positive cells per 1,000 cells was 11.86 +/- 0.45 in the control group. IL-1b significantly stimulated the proliferation ratio (15.30 +/- 0.88; p < 0.01) and this effect could be prevented by addition of IL-1rAb. The antibody caused also a well-marked inhibition of cell growth ratio (8.23 +/- 0.67; p < 0.01). The plasma corticosterone concentration was higher in IL-1b-treated animals than in the control group, 107.79 +/- 2.82 vs. 61.08 +/- 2.0 ng/ml, respectively, p < 0.01. On the other hand, IL-1rAb decreased corticosterone secretion (31.53 +/- 2.58 ng/ml, p < 0.01) and reversed the stimulatory effect of of IL-1b. In contrast, IL-1a seemed to have no influence on adrenocortical regeneration. In conclusion, this study supported the thesis of close interconnection between immune and endocrine systems and revealed that IL-1b could act as a growth-promoting factor on regenerating adrenal cortex in the rat.

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Although there is little evidence that melatonin may have a direct antimitotic effect on various cells, it has been shown that this pineal compound may influence the cell proliferation of either normal or neoplastic cells. Therefore, the influence of melatonin on the mitotic activity of regenerating adrenal cortex of rats was studied. The mitotic activity was counted in the adrenal cortex or rats on days 2, 7, and 12 following enucleation of the adrenals. Melatonin did not influence the mitotic activity of regenerating adrenal cortex in the rat.