Transcortin is the plasma protein that specifically recognises cortisol. Forty years ago with a series of studies, we made a transcortin specific antibody that also recognised cortisol binding proteins on the surface of lymphocytes (1) and intracellular proteins of cortisol responsive cells (2-4). Remarkably, to my knowledge the question asked has not been made. Perhaps a young scientist member of RG is interested in pursuing the question.

1. Werthamer S, Samuels AJ, Amaral L. Identification and partial purification of "transcortin"-like protein within human lymphocytes. J Biol Chem. 1973 Sep 25;248(18):6398-407. PubMed PMID: 4125868.

2. Werthamer S, Govindaraj S, Amaral L. Placenta, transcortin, and localized immune response. J Clin Invest. 1976 Apr;57(4):1000-8. PubMed PMID: 820715; PubMed Central PMCID: PMC436743.

3. Amaral L, Lin K, Samuels AJ, Werthamer S. Human liver nuclear transcortin. Its postulated role in glucocorticoid regulation of genetic activity. Biochim Biophys Acta. 1974 Sep 5;362(2):332-45. PubMed PMID: 4371272.

4. Amaral L, Samuels AJ, Werthamer S. Transport of cortisol by cultured chronic lymphocytic leukemic lymphocytes. Experientia. 1971 May 15;27(5):511-2. PubMed PMID: 5132576.

5. Werthamer S, Amaral L. The response of leukemic lymphocytes to cortisol: a suggested role of transcortin. Blood. 1971 Apr;37(4):463-72. PubMed PMID:5549720.

6. Amaral L, Werthamer S. Identification of breast cancer transcortin and its inhibitory role in cell-mediated immunity. Nature. 1976 Aug 12;262(5569):589-90. PubMed PMID: 8726.