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Identification and Description of G, L
and S Mucus At the end
of 1968 1 had identified and characterized two types of
mucus, one with a high viscosity (G) the other with a low
viscosity (E). E mucus was stimulated by oestrogens and G
mucus by progesterone, G mucus being produced in G
crypts, E mucus in E crypts. Also we isolated the liquid
phase (aqueous, in the lattice structure) of mucus. This
phase was named secretion B since it resembled blood
serum (Odeblad and Rosenberg 1968). The B component is
temporarily secreted in excess during an hour after
mechanical stimulation of the cervix. Like the P mucus
(as will be discussed below) it may carry enzymes from
the isthmus region downwards in the cervical canal. The B
secretion will be discussed in more detail in a
forthcoming paper.
Research
during the years 1970 to 1975 indicated that the
progression of spermatozoa in E mucus was complicated and
it was evident that E mucus was composed of two different
types of mucus, named S (-sperm-transmission) mucus and L
(- locking-in) mucus because of the capacity of that
mucus to attract and enclose malformed sperm (Figure 5).
These results were published (Odeblad 1977, 1978; H”glund and Odeblad
1977) and the G - L - S model was able to explain the
major factors associated with the upward movement of
sperm in the cervical canal.
The
discovery of G, L and S mucus was presented for the first
time at the University of Surrey, England, in 1976, and
later at Rottach-Egern, Stockholm, New Delhi, Seattle,
and in Sydney, Australia, in 1977. Most of the audiences
did not understand how to apply this new knowledge. Dr
Max Elstein of England readily accepted the G - L - S
model but Dr Kevin Hume of Sydney, Australia, appreciated
the significance of the discovery. Dr Hume was a member
of the Billings group and he
drew my attention to the fact that G mucus would be
present in the infertile phase of the woman's menstrual
cycle, and L and S types during the fertile phase, and
also that S mucus would correspond with the Peak day.
This was the beginning of my participation, collaboration
and commitment to the Billings Ovulation Method.
Following Dr Hume's recommendations, I showed for cycles
of different lengths, and in women of different ages,
that the agreement was statistically significant. This
finding was presented at a number of conferences in
several countries, towns and universities, for example in
Acapulco in 1982 (published in 1983), in Melbourne in
1983 and in Paris in 1986 (Odeblad 1987).
Figure 5. Viscosities of
micro-samples of different types of mucus.
Studies (Odeblad et al. 1984)
showed that S mucus was very fluid (Figure 5) and that
sperm cells moved along the canal very rapidly in S
mucus, reaching the S crypts in 3-10 minutes. L mucus had
a medium viscosity. Unit structures of L mucus attracted
malformed sperm cells or those which moved slowly, and
this "filtration" of sperm cells is efficacious
(Odeblad 1985). G mucus has a high viscosity and forms a
sort of impenetrable plug (Odeblad et al. 1983).
If we take a macrosample of
cervical mucus and allow it to spread out on a glass
slide we are able to see with the aid of a microscope
some interesting patterns (Figure 6). L mucus shows very
fine crystals in the shape of rectangular leaves. In S
mucus one sees crystals of another configuration --
small, thin needles. G mucus does not exhibit any
crystals, but epithelial cells, leucocytes and
lymphocytes. The nuclei of these cells are very abundant
(Figure 7). NMR studies indicate that the water of S
mucus is associated with the mucus in such a way as to
form a structure which facilitates the forward movement
of sperm cells (Figure 8; Odeblad 1966a).
(a)
(b)
Figure 6. All mucus
types present in one cervical sample obtained from a
virgin woman 18 years old. Figure 6(a) shows types L (x
30), S (x 80), G- (x 80) and G+ (x 160). Note that the
magnifications are all different for the different types.
Figure 6(b) shows the secretions P6 (x 80), Pa (x 80), F
(x 480), and Z (x 320). The F secretion contains a few
leucocytes (rounded cells) among the epithelial cells
(elongated) because some G secretion overlaps the F
mucus. In the picture of the Z secretion one can see (to
the bottom) the enzyme grains tend to aggregate into ring
formed structures. To the top grains are absorbed on Pa
mucus. Note that the magnifications are different for the
various photos. The sample was taken the day after
ovulation, approximately 17 hours after the ovulation had
taken place. The woman was healthy and the large amount
of leucocytes and lymphocytes in the G+ sample is a
normal phenomenon.
Figure 7. Comparison of
G+ mucus with F mucus. G+ mucus has more leucocytes and
lymphocytes. None of these cells are found in F mucus,
only epithelial cells. (x 600)
In 1983 1 had the privilege of
working with Drs John and Evelyn Billings in Melbourne
and also with Professor James Brown and other research
workers of the Ovulation Method. The hormonal response of
G, L, and S mucus was studied. We found that L mucus was
stimulated by medium and increasing levels, and S mucus
by high levels, of oestrogen. Later I showed that S mucus
was also stimulated by noradrenaline. G mucus was
stimulated by progesterone. In the first infertile phase
of the cycle the progesterone level is low, but
sufficient to stimulate G crypts feebly (G-mucus).
After ovulation, progesterone levels are high and
stimulate G crypts strongly. This G mucus is very dense
(G+ mucus).
Figure 8.
Enlarged NMR spectra of S, L and G+ mucus compared with
that of water. This investigation demonstrated
hydrogen-bonding in the aqueous phases (A) of S,
L, and G+ mucus. Waves H and M are reference
signals which enable the position of the aqueous signals
to be obtained with very high precision. The wave shifts
indicate that the water of S mucus has a small resistance
to sperm cells but that of G+ mucus presents a much
greater resistance.
Usually no sensation is
associated with G mucus, and the days are dry during the
infertile phases. When oestrogen levels increase L mucus
begins to be produced, and wetness is felt, firstly with
a sticky sensation. Later, when oestrogen levels are
high, and S mucus is also produced, there is a slippery
or lubricative sensation (Figure 15), and this
sensation remains until the Peak day. On that day
oestrogen levels are already decreasing but the
noradrenaline-like activity of the sympathetic nervous
system causes stimulation of the S mucus. Figure
15 shows the temporal relations of the different
secretions. After the Peak day G mucus is
accompanied by a return to a dry sensation due to the
abundant secretion of progesterone by the corpus luteum.
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