Researchers found that a protein called sortilin (or similar versions of it) is present in the GnRH‑producing neurons of both young and old cows. The amount of sortilin‑related protein was a bit higher in certain brain regions of older animals, but the gene’s RNA levels didn’t change much with age. The study is mostly basic science and doesn’t give any tips on using gonadorelin or other peptides for health or performance.

Ageing is associated with reduced fertility, yet the neuronal basis of reproductive decline remains poorly understood. Alpha-synuclein (αSYN), a protein implicated in neurodegeneration, accumulates in bovine gonadotrophin-releasing hormone (GnRH) neurons during ageing. Sortilin 1 (SORT1), an endocytic receptor for pathogenic αSYN fibrils, may be relevant to this process. To examine SORT1 expression in hypothalamic GnRH neurons of young heifers and aged cows, and to assess possible regional and age-related differences. SORT1 mRNA and protein were analysed by RT-PCR, quantitative RT-PCR, and western blotting in bovine cortex, hippocampus, and hypothalamic regions, including the preoptic area (POA), arcuate nucleus (ARC), and median eminence (ME). Co-localisation with GnRH was examined by immunofluorescence and confocal microscopy. Expression was also examined in immortalised GnRH neurons (GT1-7). SORT1 transcripts were detected in all brain regions examined and in GT1-7 cells. Western blotting revealed multiple SORT1-like immunoreactive bands in each region, with overall stronger signals in the posterior hypothalamus (ARC and ME) of aged cows. Transcript levels showed no clear age-related differences. Confocal microscopy demonstrated SORT1-like immunoreactivity in GnRH-positive neurons in both age groups. Bovine GnRH neurons express SORT1-like immunoreactivity, indicating the presence of proteins related to SORT1 in these cells. The multiple immunoreactive bands observed may reflect isoforms, processing, or antibody cross-reactivity; however, their identities remain to be confirmed. These findings provide evidence for SORT1-like expression in bovine GnRH neurons, forming a basis for future studies on its potential role in reproductive ageing.