Rabbit aorta and rat fundus do not display tachyphylaxis to angiotensin II ([Asp1]angiotensin II) at 37.degree. C. These tissues display tachyphylaxis to [Sar1]angiotensin II ((#-methylglycine1]angiotensin II) and [dimethylglycine1]angiotensin II, respectively, at this temperature. At 22.degree. C, both tissues displayed rapid tachyphylaxis to [Asp1]angiotensin II which was reversed on prolonged incubation in peptide-free medium. At 37.degree. C, but at a lower than normal pH (pH 6.5 instead of 7.4), the rabbit aorta developed rapid tachyphylaxis to [Asp1]angiotensin II; this effect was reversed on prolonged incubation in peptide-free medium. The rat uterus, at 30.degree. C, displayed tachyphylaxis to [Asp1]angiotensin II and analogs in order of rate of onset: [Sar1]angiotensin II > [Asp1]angiotensin II .mchgt. [des-Asp1]angiotensin II. Over 1/2 of the individual uterine strips tested displayed no tachyphylaxis to [des-Asp1]angiotensin II. At 22.degree. C tachyphylaxis to all 3 compounds was rapid on onset and was reversed on prolonged incubation. A correlation is indicated between affinity of the peptide analog for angiotensin receptor and its ability to induce tachyphylaxis. A possible involvement of membrane-bound enzymes in the onset and duration of tachyphylaxis is suggested.