Functional maturation of the epididymis in the rat.

Weight, histological and biochemical changes in the rat epididymis were investigated during prepubertal, pubertal and postpubertal periods. The phase of most rapid growth of the epididymis commenced at 21 days and extended to 60 days of age; this period corresponded closely to the onset of androgen production at 3 weeks and stabilization of the leydig cell number at 60 days. Histological differentiation in the caput epididymis started before sperm entry and was complete in the cauda only several days after the spermatozoa had appeared. The presence of appreciable quantities of glycerophosphorylcholine (GPC) and sialic acid in the epididymis of 21-day-old rats suggested inherent secretory ability of the epididymal epithelium. The concentrations of GPC, sialic acid, phospholipids and glycogen in the epididymis gradually increased with age, but each came under the influence of androgen at a different age. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Maximal secretory activity of the epididymis became established only by 90 days of age.