Sex steroid hormones influence the cAMP content in human endometrium during the menstrual cycle

The measurement of the tissue concentrations of cyclic adenosine monophosphate (cAMP) in human endometrium shows that the levels of the nucleotide vary during the menstrual cycle, being 11.4 +/- (SE) 2.5 and 37.7 +/- (SE) 10.1 pmol/mg protein in the proliferative and secretory phase, respectively. The individual determinations of cAMP are significantly correlated to the estradiol/progesterone blood concentration ratio: by this means we obtained a superimposable distribution with the results of histologic examination suggesting that the hormones have a direct action in determining the cAMP levels in this tissue. The relevance of these observations for the physiology of the endometrium is discussed.