Expression and distribution of GPR55 and GPR119 during the development of rat testis

G Protein-Coupled Receptors, GPR55 and GPR119 are widely distributed throughout the body and exert important biological functions. However, little is known about their roles in testis. This study aimed to examine the expression and distribution of GPR55 and GPR119 during the development of the rat testis. Sixty male Sprague Dawley rats (180-240 g) were divided into 10 groups as 7, 14, 21, 28, 35, 42, 49, 56, 63, and 70 postnatal days of age (PND) (six animals per group). The testicular expression of GPR55 and GPR119 has been investigated by immunohistochemistry, Western blot, and quantitative RT-PCR methods. We observed that GPR55 and GPR119 are expressed throughout the rat testis development from PND 7 to 70. However, no difference was observed between the groups in terms of expression levels, except for GPR55 mRNA expression in the group of PND 7. Immunohistochemistry analysis showed that GPR55 is expressed in spermatids and spermatocytes in the mid-term tubules and spermatocytes in the late-stage tubules in groups of PND 56, 63, and 70. For GPR119, very intense positivity was observed only in spermatids in the mid-term (stage VII-VIII) tubules in the groups of PND 56, 63, and 70. No significant difference was observed in the number of GPR55 and GPR119 positive cells in testes from PND 56 through PND 70. Taken together, both GPR55 and GPR119 receptors are expressed throughout the rat testis development (PND 7 to 70). These results suggest that GPR55 and GPR119 are involved in the modulation of male reproductive function.