Circulating cortisol levels after exogenous cortisol administration are higher in women using hormonal contraceptives: data from two preliminary studies

Abstract

Exogenous cortisol administration has been used to test the influence of glucocorticoids on a variety of outcomes, including memory and affect. Careful control of factors known to influence cortisol and other endogenous hormone levels is central to the success of this research. While the use of hormonal birth control (HBC) is known to exert many physiological effects, including decreasing the salivary cortisol response to stress, it is unknown how HBC influences circulating cortisol levels after exogenous cortisol administration. To determine those effects, we examined the role of HBC on participants’ cortisol levels after receiving synthetic cortisol (hydrocortisone) in two separate studies. In Study 1, 24 healthy women taking HBC and 26 healthy men were administered a 0.1 mg/kg body weight intravenous dose of hydrocortisone, and plasma cortisol levels were measured over 3 h. In Study 2, 61 participants (34 women; 16 were on HBC) received a 15 mg hydrocortisone pill, and salivary cortisol levels were measured over 6 h. Taken together, results from these studies suggest that HBC use is associated with a greater cortisol increase following cortisol administration. These data have important methodological implications: (1) when given a controlled dose of hydrocortisone, cortisol levels may increase more dramatically in women taking HBC versus women not on HBC or men; and (2) in studies manipulating cortisol levels, women on hormonal contraceptives should be investigated as a separate group.

• Birth control
• glucocorticoids
• HPA axis
• hydrocortisone
• intravenous
• oral
• sex differences

Acknowledgements

Study 1: The authors are grateful to the UW CTRC nursing staff and to research assistants C. Burzinski, C. Cenek, B. Nanzig, S. Scherer, S. Sharma and K. Swinsky for help with data collection, as well as N. Kalin, G. Nash and P. Roseboom for assistance with hormone assays. Study 2: the authors are grateful to E. McAuliff, P. Singh, C. Burzinski, B. Gauthier, K. Krol, A. Benson, L. Burk, J. Gogan, E. Blum Ng, J. Pikorz, N. Shallow, N. Speck, H. Schaefer, J. Halverson, J. Alt, M. Peterson and the Waisman Laboratory for Brain Imaging and Behavior staff for their assistance with data collection. The authors are also grateful to C. Kirschbaum, who conducted salivary cortisol assays for Study 2, and to N. Kalin, R. Davidson and E. Young for advice and support.

Notes

¹Using AUCg as the dependent variable, there was also a significant sex difference after hydrocortisone infusion, t[42] = 14.24, p < 0.001, CI: 3052.95 to 4061.05, with higher AUCg in women [M: 6613.74, SD: 951.24] compared to men [M: 3056.74, SD: 683.80].