As far as I know, there are no good, recent data evaluating the effects
of varying protein/fat mixtures upon insulin/glucagon responses in
humans.   Most of the data involves manipulating CHO, with varying
amounts of fat; protein is usually held constant.   The Westphal et al
paper (1) evaluates protein/CHO mixtures on serum  glucagon responses.
Pure dietary CHO (50 gm glucose) shows no rise in plasma glucagon
whereas pure protein (actually 93.5% lean beef, 6.5% fat) causes the
greatest rise in glucagon after 1hr; with roughly equal areas under the
curve after 3hrs when comparing pure protein to protein/CHO mixtures (50
gm glucose/50 gm protein).   Thus, there appears to be a dose response
with protein/CHO mixtures and from the data, it can probably be
interpreted  that there is a dose response effect with pure protein.
Fat/CHO mixtures cause a greater rise in insulin that CHO meals alone,
presumably because of the stimulatory effect of fat upon glucose
dependent insulinotropic peptide (GIP) (2).   Thus, as Todd has
surmised, there is a dose dependent effect of dietary protein upon
glucagon secretion which is largely independent of either CHO or Fat.

                                REFERENCES

1.      Westphal SA et al.  Metabolic response to glucose ingested with
various amounts of protein.  Am J Clin Nutr 1990;52:267-72.
2.      Collier GR et al.  The acute effect of fat on insulin secretion.
J Clin Endocrionology and Metabolism 1988;66:323-26.