The previously demonstrated correlation between the ocular pressure rise after topical application of corticosteroids and the plasma cortisol value after oral administration of dexamethasone as well as the previously demonstrated genetic nature of the former suggest that the latter is also heritable. In a study of 98 nuclear family groups, initial and final plasma cortisol levels were determined between 5 and 7 PM on successive days. The final cortisol was taken 24 hours after 0.75 mg of dexamethasone was administered orally. No clearcut evidence of heritability among first degree relatives was noted. An unexpected finding was a significant correlation between husband and wife pairs.
Levene RZ, Schwartz B, Workman PL. Heritability of Plasma Cortisol. Arch Ophthalmol. 1972;87(4):389-391. doi:10.1001/archopht.1972.01000020391004