VASCULAR-PERMEABILITY TO EFFECTORS OF THE IMMUNE-SYSTEM IN THE MALE-RAT REPRODUCTIVE-TRACT AT PUBERTY

The net movements and distribution volumes of IgG in the pubertal rat testis and epididymis were measured using physiological techniques. A new method to calculate vascular permeabilities was developed. The vol ume of testicular extracellular fluid accessible to IgG (V-eq, mu l/g) increased between 20 and 30 days of age and remained above 20-day-old levels. Estimates of the surface areas of the exchange vessels (S, cm (2)) increased with age, most between 20 and 30 days of age. The speed at which equilibrium between tissue extracellular fluid and serum was reached (K, min(-1)) increased between 20 and 30 days and decreased b etween 44 and 60 days of age. The lymph flow (Q(L)) and estimates of p ermeabilities (P) to IgG increased between 20 and 30 days of age and r emained high. In the caput epididymidis V-eq increased between 30 and 60 days and S between 44 and 60 days of age, but K increased between 3 0 and 44 days and decreased between 44 and 60 days of age. Q(L) and th e estimates of P increased between 20 and 44 days of age and remained at that level. In the corpus epididymidis, V-eq did not change with ag e, but S increased between 30 and 60 days and K, Q(L) and P between 20 and 44 days of age. In the cauda epididymidis, there were no obvious changes in V-eq with age, but the estimates of S increased and K value s decreased between 44 and 60 days of age. Q(L) and P increased betwee n 30 and 44 days and then decreased. After 30 days of age the values f or V-eq K, Q(L), and S were larger in the testis than in the cauda, wh ereas P at 44 days of age was not different. The number of perivascula r mononuclear cell infiltrate profiles per 1000 epididymal tubule cros s-sections increased with age in the caput epididymidis, but no infilt rates were observed in the corpus or cauda before 60 days of age.