biostudies-literatureYing YXinjiang Tian-Chi Talents Introduction ProgramNational Natural Science Foundation of China123https://www.ebi.ac.uk/biostudies/studies/S-EPMC11851772biostudies-literatureUnknown14(2)Commonly in seasonal breeding animals, testicular development is inhibited prior to Sertoli cell maturation when environmental conditions become unfavorable, with recovery occurring once conditions improve. However, the precise molecular mechanisms governing this process remain unclear. We investigated the role of androgen receptor (AR) in the seasonal regulation of testicular development in a wild population of <i>Rattus norvegicus caraco</i>, a subspecies of brown rats in Northeast China residing in high-latitude regions, known for its seasonal reproductive patterns. Our results revealed a significant increase in <i>Ar</i> mRNA expression in wild rats with small testes less than 0.2 g and body weights ranging between 80 and 100 g during the nonbreeding season. Further examinations of <i>BiologyAndrogen Receptor Expression Governs the Seasonal Inhibition of Testicular Development and Subsequent Recovery in <i>Rattus norvegicus caraco</i>.PMC11851772no32090022; 319722853197228532090022Liu XWang DYing YWang LLi NSong YfalseAndrogen Receptor Expression Governs the Seasonal Inhibition of Testicular Development and Subsequent Recovery in <i>Rattus norvegicus caraco</i>.Commonly in seasonal breeding animals, testicular development is inhibited prior to Sertoli cell maturation when environmental conditions become unfavorable, with recovery occurring once conditions improve. However, the precise molecular mechanisms governing this process remain unclear. We investigated the role of androgen receptor (AR) in the seasonal regulation of testicular development in a wild population of <i>Rattus norvegicus caraco</i>, a subspecies of brown rats in Northeast China residing in high-latitude regions, known for its seasonal reproductive patterns. Our results revealed a significant increase in <i>Ar</i> mRNA expression in wild rats with small testes less than 0.2 g and body weights ranging between 80 and 100 g during the nonbreeding season. Further examinations of <i>2025-01-01T00:00:00Z2025 Jan2026-04-08T18:55:29.625Z2025-04-07T11:26:20.097ZS-EPMC118517724000189110.3390/biology14020123