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Hypothalamic-pituitary-adrenal axis activity during exercise in African American and Caucasian women.
J Clin Endocrinol Metab. 2000 Aug; 85(8):2660-3.JC

Abstract

African American women have a greater prevalence of obesity than Caucasian women, but the reasons for this difference are not known. We have investigated whether activity of the hypothalamic-pituitary adrenal axis plays a role in this phenomenon. Previous studies have shown that plasma ACTH immunoreactivity (ACTH-IR) of African American women, measured after ovine CRH (oCRH) stimulation, is significantly greater than ACTH-IR of Caucasian women, but is not accompanied by greater plasma cortisol concentrations. Analysis by high pressure liquid chromatography has demonstrated that after oCRH stimulation, the plasma ACTH-IR of African American women contains many nonintact ACTH fragments not found in Caucasians. To determine whether these racial differences in ACTH-IR secretion are an artifact of exogenous oCRH administration or are also found after a physiological stimulus for ACTH secretion, we measured hormones of the hypothalamic-pituitary adrenal axis before and after a standardized, maximal exercise treadmill test in 16 African American and 19 Caucasian healthy women matched for age, socioeconomic status, and body mass index. The intensity of exercise performed was similar in the two groups, as determined by duration of exercise, perceived intensity of exertion, plasma lactate, maximal heart rate, and maximum oxygen uptake. Basal ACTH-IR measured by RIA or immunoradiometric assay and cortisol were similar in African Americans and Caucasians. Plasma ACTH-IR, measured 10 min after completion of exercise, was significantly greater in African Americans than in Caucasians [by RIA: mean +/- SD ACTH-IR, 47.1 +/- 30.9 vs. 25.4 +/- 16.7 pmol/L (P < 0.01); by immunoradiometric assay: ACTH-IR, 45.9 +/- 43.2 vs. 21.1 +/- 14.6 pmol/L (P < 0.05)]. However, plasma cortisol after exercise was not different (450.2 +/- 157.7 vs. 483.6 +/- 180.4 nmol/L; P = 0.57). We conclude that ACTH-IR is significantly greater in African American than in Caucasian women after intense exercise. The ACTH-IR of African Americans and Caucasians does not appear to be equipotent at adrenal melanocortin-2 receptors, because the greater ACTH-IR of African Americans does not lead to greater cortisol secretion. Whether some components of the ACTH-IR detected in African Americans affect signal transduction of the hypothalamic melanocortin-4 receptors implicated in body weight regulation and thus predispose African American women to weight gain without altering plasma cortisol remains to be determined.

Authors+Show Affiliations

Unit on Growth and Obesity, Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1862, USA. JYISi@NIH.GovNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10946862

Citation

Yanovski, J A., et al. "Hypothalamic-pituitary-adrenal Axis Activity During Exercise in African American and Caucasian Women." The Journal of Clinical Endocrinology and Metabolism, vol. 85, no. 8, 2000, pp. 2660-3.
Yanovski JA, Yanovski SZ, Boyle AJ, et al. Hypothalamic-pituitary-adrenal axis activity during exercise in African American and Caucasian women. J Clin Endocrinol Metab. 2000;85(8):2660-3.
Yanovski, J. A., Yanovski, S. Z., Boyle, A. J., Gold, P. W., Sovik, K. N., Sebring, N. G., & Drinkard, B. (2000). Hypothalamic-pituitary-adrenal axis activity during exercise in African American and Caucasian women. The Journal of Clinical Endocrinology and Metabolism, 85(8), 2660-3.
Yanovski JA, et al. Hypothalamic-pituitary-adrenal Axis Activity During Exercise in African American and Caucasian Women. J Clin Endocrinol Metab. 2000;85(8):2660-3. PubMed PMID: 10946862.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hypothalamic-pituitary-adrenal axis activity during exercise in African American and Caucasian women. AU - Yanovski,J A, AU - Yanovski,S Z, AU - Boyle,A J, AU - Gold,P W, AU - Sovik,K N, AU - Sebring,N G, AU - Drinkard,B, PY - 2000/8/18/pubmed PY - 2000/9/2/medline PY - 2000/8/18/entrez SP - 2660 EP - 3 JF - The Journal of clinical endocrinology and metabolism JO - J Clin Endocrinol Metab VL - 85 IS - 8 N2 - African American women have a greater prevalence of obesity than Caucasian women, but the reasons for this difference are not known. We have investigated whether activity of the hypothalamic-pituitary adrenal axis plays a role in this phenomenon. Previous studies have shown that plasma ACTH immunoreactivity (ACTH-IR) of African American women, measured after ovine CRH (oCRH) stimulation, is significantly greater than ACTH-IR of Caucasian women, but is not accompanied by greater plasma cortisol concentrations. Analysis by high pressure liquid chromatography has demonstrated that after oCRH stimulation, the plasma ACTH-IR of African American women contains many nonintact ACTH fragments not found in Caucasians. To determine whether these racial differences in ACTH-IR secretion are an artifact of exogenous oCRH administration or are also found after a physiological stimulus for ACTH secretion, we measured hormones of the hypothalamic-pituitary adrenal axis before and after a standardized, maximal exercise treadmill test in 16 African American and 19 Caucasian healthy women matched for age, socioeconomic status, and body mass index. The intensity of exercise performed was similar in the two groups, as determined by duration of exercise, perceived intensity of exertion, plasma lactate, maximal heart rate, and maximum oxygen uptake. Basal ACTH-IR measured by RIA or immunoradiometric assay and cortisol were similar in African Americans and Caucasians. Plasma ACTH-IR, measured 10 min after completion of exercise, was significantly greater in African Americans than in Caucasians [by RIA: mean +/- SD ACTH-IR, 47.1 +/- 30.9 vs. 25.4 +/- 16.7 pmol/L (P < 0.01); by immunoradiometric assay: ACTH-IR, 45.9 +/- 43.2 vs. 21.1 +/- 14.6 pmol/L (P < 0.05)]. However, plasma cortisol after exercise was not different (450.2 +/- 157.7 vs. 483.6 +/- 180.4 nmol/L; P = 0.57). We conclude that ACTH-IR is significantly greater in African American than in Caucasian women after intense exercise. The ACTH-IR of African Americans and Caucasians does not appear to be equipotent at adrenal melanocortin-2 receptors, because the greater ACTH-IR of African Americans does not lead to greater cortisol secretion. Whether some components of the ACTH-IR detected in African Americans affect signal transduction of the hypothalamic melanocortin-4 receptors implicated in body weight regulation and thus predispose African American women to weight gain without altering plasma cortisol remains to be determined. SN - 0021-972X UR - https://www.unboundmedicine.com/medline/citation/10946862/Hypothalamic_pituitary_adrenal_axis_activity_during_exercise_in_African_American_and_Caucasian_women_ L2 - https://academic.oup.com/jcem/article-lookup/doi/10.1210/jcem.85.8.6708 DB - PRIME DP - Unbound Medicine ER -