Expression of somatostatin and cDNA cloning in the thymus of the African ostrich

The thymus in addition to being a central lymphoid organ is also an endocrine organ which produces various neuropeptides that influence the function of this gland. Somatostatin is a neuropeptide that was isolated initially in the hypothalamus and which inhibits the release of growth hormone. The distribution of somatostatin-producing cells and the sequence of somatostatin have been determined in many species. In the present study, we investigated the expression of somatostatin in the thymus of the African ostrich and its sequence by reverse-transcriptase polymerase chain reaction and immunohistochemistry. The results showed that somatostatin mRNA was expressed in the thymus and somatostatin immunoreative cells were distributed in both the cortical and medullary regions of the thymus. Results of cDNA cloning revealed that the nucleotide sequence and the encoded protein of African ostrich somatostatin were 348 bases and 116 amino acids in length and that it is highly conserved to that of other reported species. These findings indicated that the somatostatin expressed in the thymus of ostrich might play an important role in the function of the gland. In addition, this research has provided novel molecular data allowing further study of somatostatin in the ostrich.