Micropuncture and microanalytical studies of rhesus monkey and baboon epididymis and the human ductus deferens

Using micropuncture and microanalytical techniques, we studied the microenvironment surrounding the maturing spermatozoa in different regions along the epididymis of the rhesus monkey (Macaca mulatta ; 3 animals) and the baboon (Papio cynocephalus ; 1 animal) and in the human ductus deferens. In the monkey and baboon, samples of luminal contents (luminal fluid and spermatozoa) of approximately 50 to 300 nanolitres were collected from several epididymal sites and the luminal fluid analyzed for inositol. Similarly, a sample of approximately 0.5 to 1.0 μl of luminal contents was collected from each human ductus deferens and the luminal fluid analyzed for sodium, potassium, chloride, inositol, carnitine, glycerophosphocholine (GPC), phosphocholine and total phosphate. Each analysis required the modification of standard methods to accommodate the very small sample volumes collected. We show that the microenvironment in the monkey, baboon, and human is different from those in other species with respect to the concentration of compounds estimated. In the luminal fluid of the human ductus deferens, the majority of the osmoticallyactive compounds are the inorganic ions which is in direct contrast to the rat, hamster, rabbit, ram and boar. In these species, organic compounds contribute significantly more to the osmolarity of the luminal fluid than do inorganic ions. Although the significance of these findings is unclear, a relationship seems to exist between the appearance of carnitine in the luminal fluid of the proximal caput epididymidis of the rat and the point where spermatozoa develop the potential for motility. These investigations also raise the question of which species most closely reflects the physiology of the reproductive system of man.