The TRHR gene encodes for thyrotropin-releasing hormone (TRH). Upon binding to TRH, this receptor activates the inositol phospholipid-calcium-protein kinase C transduction pathway.
A medium to high impact genetic variation in this gene has been associated with generalised thyrotropin-releasing hormone resistance. The TRHR gene stimulates the release of thyroid hormones T3 and T4 leading to an increased metabolic rate which is required to mobilise fuels during exercise.
The TT- allele has been linked to lean body mass while the C-allele is associated with thyrotrophin hormone resistance.
Exercise, cold swims/showers, and caloric restriction have been known to improve TRH function.