Statistical evaluation of coincident prolactin and luteinizing hormone pulses during the normal menstrual cycle
Date
1988-10Author
Steiner, Robert A.
Bremner, William J.
Soules, Michael R.
Clifton, Donald K.
Aksel, Sezer
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Show full item recordAbstract
The purpose of this work was 2-fold. First, we sought to develop
statistical criteria by which it could be established that the coincident
occurrence of pulses of two different hormones exceeds that which would
occur by chance alone, thereby suggesting that secretion of the two
hormones is either coupled or controlled from a single source generator.
Using computer simulations of uncoupled pulse generators operating at
different frequencies, we were able to derive the appropriate statistical
criteria and to apply them to achieve our second objective, to determine
whether the occasional coincidence of plasma LH and serum PRL pulses that
occurs throughout the menstrual cycle in normal women exceeds that which
would happen by chance. The results of the computer simulations indicated
that pulses emanating from two completely independent oscillators will
occur coincidently at a predictable rate, despite the fact that the
generator sources are not coupled; moreover, the rate of coincidence is
increased when the pulse frequency of one of the source generators is
increased. Using this knowledge and the statistical criteria we derived,
we analyzed the coincidence of LH and PRL pulses in five normal women
during their early follicular, late follicular, and midluteal phases and
in another five women during their late luteal phase. We found that the
number of PRL pulses that occurred coincidently with LH pulses
consistently exceeded that which would be predicted if the two pulse
generators were operating completely independently of one another;
however, only during the late follicular and late luteal phases was the
coincidence level between LH and PRL pulses sufficiently high in a
sufficient number of women to conclude that there was coupling between the
pulse sources. These studies suggest, first, that stringent and rigorous
statistical criteria must be applied to the analysis of spontaneously
coincident secretory phenomena before it can be deduced that two pulse
generators are indeed coupled, and second, that the pulse generators
governing the secretion of PRL and LH are probably coupled, at least
during certain phases of the menstrual cycle.