['To explore the influence of buried penis on nitric oxide synthase (NOS) activity of the corpus cavernosum in rats.', 'The experimental model of concealed penis was established by intra-pocket-suture of the root of the penis. Two hundred and forty rats were equally randomized into a 2, a 4 and a 6 months group, each further divided into a buried (n = 50), a sham operation (n = 15) and a normal subgroup (n = 15). The development of the corpus cavernosum was surveyed by measuring its weight and the ratio to the body weight, followed by determination of NOS activity in the corpus cavernosum by spectrophotometry.', 'No significant differences were found in the corpus cavernosum weight, the body weight and their ratio among the buried, sham operation and normal groups in any experimental stage (P > 0.05). Buried penis decreased NOS activity in the 4- and 6-month groups (P < 0.05 and P < 0.01) compared with the normal group, but effected no significant change in the 2-month group.'] Does [ Buried penis decrease nitric oxide synthase of the corpus cavernosum ]?