Expression of MMP transcripts during the menstrual cycle in rhesus macaques. MMP expression was assayed by Northern Hybridization and expressed as a percent of the maximum for the group. Values were analyzed previously [6,7] by ANOVA followed by Fisher's Protected LSD. In each case MMPs were maximal during the menstrual period at the beginning of the proliferative phase. Bars with similar subscripts were significantly different (P < 0.05) from those without subsubscripts.