1. A permeability barrier in or around the seminiferous tubules of rams has been demonstrated by studying the rate of passage of a variety of substances from blood plasma into fluid collected from the rete testis and into testicular lymph.2. All substances studied passed readily into testicular lymph.3. Tritiated water, urea, ethanol and bicarbonate in rete testis fluid equilibrated with blood plasma within 3 hr; Na(+), K(+), Rb(+), Cl(-), I(-), CNS(-), creatinine and galactose entered slowly and p-aminohippurate (PAH), glutamate, iodinated albumin, inulin and [(51)Cr]EDTA did not appear in rete testis fluid at all.4. Rubidium was excluded relative to iodoantipyrine from the testes of control and hypophysectomized rats and from rat testes heated to 37, 40, 43 and 45 degrees C; no such exclusion was seen in testes of rats which had been given cadmium chloride 5 months earlier so as to destroy the seminiferous tubules.5. It is suggested that this permeability barrier will regulate the access to the seminiferous epithelium of some constituents of blood plasma, isolate the germinal cells immunologically and help to maintain the concentration differences between rete testis fluid and lymph or blood plasma.

Albumins↗

PubMed1969

Metabolism, sperm and fluid production of the isolated perfused testis of the sheep and goat.

1. A total of nineteen ram and three goat testes have been perfused in isolation at 34-35 degrees C for 3(1/2)-9 hr with heparinized blood and an added 5-HT antagonist (bromolysergic acid diethylamide) and their function compared with that of the normal ram testes in vivo.2. The metabolism of the perfused testes and the testes in vivo was similar but blood flow through the perfused testes was two to three times normal.3. Vasoconstriction was produced by adrenaline and noradrenaline (10-20 mug I.A.) and by electrical stimulation of nerves in the spermatic cord or of the lumbar sympathetic chain; these responses were abolished or reduced by phenoxybenzamine.4. Flow of fluid from the rete testis continued only if ischaemia was reduced to a minimum and glucose concentration in the blood perfusing the testis was kept above about 25 mg/100 ml.; the fluid secreted during perfusion was of normal composition.5. The perfused testis showed no evidence of autoregulation and the flow of fluid was not affected by changes in perfusion pressure.6. When the temperature of three testes was raised to 40 degrees C for 2 hr, metabolism increased but blood flow was unaltered; the flow of fluid and the concentration of spermatozoa decreased during heating.7. The testes perfused at normal scrotal temperatures (34-35 degrees C) were histologically normal but some abnormalities were observed in the heated testes.

Animals↗

PubMed1969