Puberty influences expression of phospholipid hydroperoxide glutathione peroxidase (GPX4) in rat testis: probable hypophysis regulation of the enzyme in male reproductive tract.

Abstract

Mammalian spermatozoa are unusually rich in polyunsaturated fatty acids, a property that predisposes them to the deleterious effects of oxygen free radicals. Mouse and human spermatozoa utilize glutathione peroxidase, (GPX), to inactivate oxygen free radicals. In the GPX super-family there is the enzyme phospholipid hydroperoxide glutathione peroxidase (GPX4) that specifically protects membrane phospholipids against peroxidation. GPX4 is present, primarily, in testis where its enzymatic activity seems to be present only after puberty. In order to clarify this question we utilized total RNA from rat testis, liver and lung to carry out cDNA synthesis and the following RT-PCR amplification of cDNA products by using specific primers of rat liver sequence. RT-PCR products of the expected size for GPX4 (525 bp) were obtained from the three tissues. At last, these fragments were submitted to sequencing analysis. Here we demonstrate that the sequence analysis of rat testis GPX4 coding region is identical to that of rat liver and lung; however puberty influences the expression pattern of rat testis GPX4. In fact Northern blot analysis of total RNA from normal and pre-puberal hypophysectomized rats demonstrates the absence of a specific GPX4 mRNA in total RNA from pre-puberal hypophysectomized rat testis; on the other hand this specific transcript is present in both normal rat testis and liver and in pre-puberal hypophysectomized rat liver. Expression pattern of GPX4 is very low in lung both in post-puberal and pre-puberal hypophysectomized rats. Therefore hypophysis could regulate GPX4 transcript in rat testis.