Evidence for expression of relaxin hormone-receptor system in the boar testis

Abstract

Although the physiological role of relaxin (RLN) in males remains largely unknown, there is limited evidence that the testis might be a candidate source and target of RLN in boars, as RLN transcripts are detected in the boar testis and it contains RLN-binding sites. To determine whether the boar testis acts as a source and target tissue of RLN, we characterised the expression pattern and cellular localisation of both RLN and its own receptor LGR7 (RXFP1) in boar testes during postnatal development by molecular and immunological approaches. Testes were collected from Duroc boars, and partial cDNA sequences of the boar homologue of human RXFP1 were identified. RLN expression increased through puberty onwards, while RXFP1 expression changed little during development.RLN mRNA and protein expression were restricted to the Leydig cells, whereas both Leydig cells and seminiferous epithelial cells expressed RXFP1 mRNA and protein.Interestingly, RLN was expressed in the testis as an 18 kDa form (the expected size of proRLN), but not as the 6 kDa mature form, during development because of a lack of the enzyme required for proRLN processing. In contrast, RXFP1 was detected at all stages as specific bands of 75 and 91-95 kDa (likely non-glycosylated and glycosylated RXFP1 respectively). Thus, we provide evidence for expression of RLN-RXFP1 ligand-receptor system in the boar testis, suggesting that the testis act as a source and possible target tissue of RLN.

Expression profiles of relaxin family peptides and their receptors indicate their influence on spermatogenesis in the domestic cat (Felis catus)

“…In pigs, relaxin mRNA and peptide expression were localized in Leydig cells at all stages of pubertal development [11,41]. In contrast to our data, the mRNA expression of the porcine RXFP1 was almost constant throughout testis development and an approximately equal mRNA expression of RXFP1 was found in all porcine testis cell fractions examined (germ cells, Sertoli cells, and Leydig cells) [41]. We detected the primary mRNA expression in the tubuli fraction.…”

“…This expression of relaxin is in accordance with the data observed in pigs, where mRNA expression measured by semiquantitative PCR increased significantly after the prepubertal stage [41]. In pigs, relaxin mRNA and peptide expression were localized in Leydig cells at all stages of pubertal development [11,41]. In contrast to our data, the mRNA expression of the porcine RXFP1 was almost constant throughout testis development and an approximately equal mRNA expression of RXFP1 was found in all porcine testis cell fractions examined (germ cells, Sertoli cells, and Leydig cells) [41].…”

“…The main relaxin receptor RXFP1 mRNA also increases significantly at this stage, but an even stronger increase (nearly 20-fold) was detectable after spermatogenesis began, and round spermatids were found in the testicular tubuli (pubertal stage II). This expression of relaxin is in accordance with the data observed in pigs, where mRNA expression measured by semiquantitative PCR increased significantly after the prepubertal stage [41]. In pigs, relaxin mRNA and peptide expression were localized in Leydig cells at all stages of pubertal development [11,41].…”

“…We detected the primary mRNA expression in the tubuli fraction. The porcine RXFP1 protein was detected in Leydig cells and seminiferous tubule cells; the latter were stained slightly more weakly [41].…”

Protective Effects of Relaxin against Cisplatin-Induced Nephrotoxicity in Rats

“…The primary antibodies were as follows: thrombomodulin antibody (kindly provided by Dr. M. Nakano, Mitsubishi Gas Chemical Co. Inc., Niigata, Japan), RLX receptor (RXFP1) [14]. The loss of thrombomodulin immunostaining was considered to represent endothelial cell damage.…”