Effects of age on the irregularity of lh and fsh serum
concentrations in women and men.
Pincus, Steven M., Johannes D. Veldhuis, Thomas Mulligan, Ali
Iranmanesh, and William S. Evans .
Steven M. Pincus, Ph.D., 990 Moose Hill Road, Guilford, CT. 06437,
Telephone: 203-458-3455, FAX: 203-458-9063
APStracts 4:0177E, 1997.
We evaluated an apparent distinction between FSH and LH dynamics:
visually, it appears that the pattern of serum concentrations of FSH
is more irregular than that of LH in younger humanfemales. We studied
healthy humans, with LH and FSH serum samples obtained every 10 min
for 24 h. Three groups were studied: N=24 younger females (N=8 early
follicular, EFol; N=8 late follicular, LFol; N=8 mid luteal, MLut);
N=8 postmenopausal females; and N=17 males, ages 21-79 yrs. To
quantify serial irregularity, we utilized ApEn, approximate entropy,
a scale- and model-independent statistic. For young females, FSH was
consistently more irregular than LH, per-subject: Pooling the younger
subjects, ApEn(FSH) - ApEn(LH) = 0.342 +/- 0.270; ApEn(FSH) >
ApEn(LH), P < 0.00001; with ApEn(FSH) > ApEn(LH) for 23 of 24
subjects. For each cycle stage, pairwise ApEn(FSH) > ApEn(LH): P
< 0.005 for both LFol and MLut, P < 0.01 for EFol. Notably, for
the post-menopausal women, the irregularity difference vanished:
ApEn(FSH)-ApEn(LH)= 0.008 +/- 0.205. Males exhibited qualitatively
similar results: ApEn(FSH)-ApEn(LH) was significantly and negatively
correlated with age (r= -0.75, P=0.0006). The capability to quantify
(the extent of) differences between FSH and LH release, beyond the
general 1-1 correspondence between primary LH and FSH pulses,
suggests a means to assess bihormonal changes as a clinical marker of
altered reproductive status in a variety of settings, e.g. a
perimenopausal milieu. Mechanistically, the erosion of unequal FSH-LH
regularity with age is consistent with a loss of synchrony control
within the integrated hypothalamo-pituitary-gonadal axis.
Received 24 April 1997; accepted in final form 6 August 1997.
APS Manuscript Number E188-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 27 August 1997