Cortisol secretory parameters in young exercisers in relation to LH secretion and bone parameters.
OBJECTIVE
Amenorrhoea and low bone density are common in excessive exercisers, yet endocrine factors that differentiate adolescent amenorrhoeic exercisers (AE) from eumenorrhoeic exercisers (EE) are unclear. We have previously reported that high ghrelin and low leptin predict lower LH secretion in AE. Leptin and ghrelin impact cortisol secretion, and hypercortisolaemia can inhibit LH pulsatility. We hypothesized that higher cortisol secretion in young endurance weight-bearing AE compared with EE and nonexercisers predicts lower LH secretion, lower levels of a bone formation marker and higher levels of a bone resorption marker.


METHODS
Cross-sectional.


METHODS
We studied 21 AE, 18 EE and 20 nonexercisers aged 14-21 years (BMI 10th-90th%iles).


METHODS
Subjects underwent frequent sampling (11 p.m. to 7 a.m.) to assess cortisol, ghrelin, leptin and LH secretory dynamics. Fasting levels of a bone formation (P1NP) and bone resorption (CTX) marker were measured.


RESULTS
BMI did not differ among groups. Cortisol pulse amplitude, mass, half-life and area under the curve (AUC) were highest in AE (P = 0.04, 0.007, 0.04 and 0.003) and were associated inversely with fat mass (r = -0.29, -0.28 and -0.35, P = 0.03, 0.04 and 0.007). We observed inverse associations between cortisol and LH AUC (r = -0.36, P = 0.008), which persisted after controlling for fat mass, leptin and ghrelin AUC. Cortisol correlated positively with CTX in EE and inversely with P1NP in nonexercisers.


CONCLUSIONS
Higher cortisol secretion in AE compared with EE and nonexercisers is associated with lower LH secretion. Effects of leptin and ghrelin on LH secretion may be mediated by increased cortisol.
Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Kathryn E
KE
Ackerman
Kamal T
KT
Patel
Gabriela
G
Guereca
Lisa
L
Pierce
David B
DB
Herzog
Madhusmita
M
Misra
D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000378:metabolism; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D054439:Ghrelin / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D020738:Leptin / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism*; D055815:Young Adult
D054439:Ghrelin; D020738:Leptin; D007986:Luteinizing Hormone; D006854:Hydrocortisone