Prolactin induces protamine 2 mRNA expression in rat testis

• Published in: Journal of Reproduction and Development Vol. 45; no. 3; pp. 205 - 212
• Main Authors: Hondo, E. (Obihiro Univ. of Agriculture and Veterinary Medicine, Hokkaido (Japan)), Kobayashi, T, Ishiguro, N, Kurohmaru, M, Kitamura, N, Yamada, J, Nagahama, Y
• Format: Journal Article
• Language: English
• Published: THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT 1999
• Subjects: DNA HYBRIDIZATION; HIBRIDACION DE ADN; HYBRIDATION D'ADN; PROLACTIN; PROLACTINA; PROLACTINE; Protamine 2; RAT; Rat testis; RATA; RATS; Subtractive DNA hybridization; TESTES; TESTICULE; TESTICULOS
• ISSN: 0916-8818; 1348-4400
• DOI: 10.1262/jrd.45.205

The effect of prolactin on transcription during spermatogenesis was examined by subtractive DNA hybridization and differential screening. A protamine 2 cDNA fragment was isolated from one of the genes up-regulated in testes of rat 6 h after prolactin injection. In situ hybridization to detect protamine 2 mRNA was also performed using digoxigenin-labeled cRNA probes. Weak signals were detected from preleptotene to early pachytene spermatocytes, elongated spermatids and spermatozoa; strong ones were recognized from mid- to late-pachytene, diplotene, and secondary spermatocytes, and early round spermatids. Localization of protamine 2 mRNA coincided with that of prolactin receptor mRNA described in our previous report. We then compared the time-dependent expression of protamine 2 mRNA with that of luteinizing hormone receptor mRNA after prolactin administration, using Northern blot analysis. Protamine 2 mRNA was up-regulated 1 h after the prolactin treatment, and stable levels were maintained for another 13 h. In contrast, luteinizing hormone receptor mRNA levels increased much later, at 13 h after prolactin injection. Therefore, protamine 2 gene responds rapidly to prolactin administration and up-regulation of expression appears to be independent of the luteinizing hormone pathway