The only established function of ORM is to act as a carrier of basic and neutrally charged lipophilic compounds. In medicine, it is known as the primary carrier of basic (positively charged) drugs (whereas albumin carries acidic (negatively charged) and neutral drugs), steroids, and protease inhibitors. Aging causes a small decrease in plasma albumin levels; if anything, there is a small increase in alpha-1-acid glycoprotein. The effect of these changes on drug protein binding and drug delivery, however, appear to be minimal. AGP shows a complex interaction with thyroid homeostasis: ORM in low concentrations was observed to stimulate the thyrotropin (TSH) receptor and intracellular accumulation of cyclic AMP. High AGP concentrations, however, inhibited TSH signalling.
Alpha-1-acid glycoprotein has been identified as one of four potentially useful circulating biomarkers for estimating the five-year risk of all-cause mortality (the other three are albumin, very low-density lipoprotein particle size, and citrate).
^Barash, Paul G. (2009). Clinical Anesthesia. p. 879.
^Zimmermann-Belsing T, Rasmussen AK, Feldt-Rasmussen U, Bøg-Hansen TC. The influence of alpha1-acid glycoprotein (orosomucoid) and its glycoforms on the function of human thyrocytes and CHO cells transfected with the human TSH receptor. Mol Cell Endocrinol. 2002 Feb 25;188(1-2):241-51. PMID 11911961
^Dietrich JW, Landgrafe G, Fotiadou EH. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis. J Thyroid Res. 2012;2012:351864. doi: 10.1155/2012/351864. Epub 2012 Dec 30. PMID 23365787
^Fischer, Kettunen, Würtz et al. "Biomarker Profiling by Nuclear Magnetic Resonance Spectroscopy for the Prediction of All-Cause Mortality: An Observational Study of 17,345 Persons.". PLoS Medicine 11(2): e1001606. doi:10.1371/journal.pmed.1001606.CS1 maint: Explicit use of et al. (link)