<p>Irisin, an adipomyokine primarily known for its role in metabolic regulation, has recently emerged as a potential regulator of reproductive function. While its ovarian actions have been partially characterised, its influence on the anterior pituitary remains largely unexplored. This study aimed to investigate the in vitro effects of irisin on the transcriptome of porcine anterior pituitary cells (APc) isolated from gilts on days 15–16 of pregnancy. Primary APc were isolated from pigs on days 15–16 of pregnancy and treated with 300 ng/mL of irisin. RNA sequencing (NovaSeq 6000, Illumina) was performed to identify differentially expressed genes (DEGs), long non-coding RNAs (lncRNAs), and alternative splicing (AS) events. Functional annotation was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Selected transcripts were validated by polymerase chain reaction (PCR) and quantitative PCR (qPCR). Irisin treatment altered the expression of 500 genes, 747 lncRNAs, and 245 transcripts undergoing AS events. Differentially expressed genes were enriched in pathways related to hormonal signalling, angiogenesis, calcium signalling, and cell remodelling. Notably, genes encoding key regulators of these processes, such as growth hormone 1, insulin-like growth factor type 1, somatostatin, prolactin receptor, and progesterone receptor, were modulated. Pathway enrichment analysis indicated enrichment of genes assigned to Janus kinase/signal transducer and activator of transcription, phosphoinositide 3-kinase/protein kinase B, and mitogen-activated protein kinase signalling cascades. This study provides the first comprehensive transcriptomic profiles of irisin action on porcine APc during early pregnancy. Irisin can modulate endocrine, structural, and molecular functions through both transcriptional and post-transcriptional mechanisms, positioning it as a novel modulator of pituitary adaptation in early gestation.</p>