Effect of Atropine on the Composition of Semen and Secretory Function of Male Accessory Organs in the Boar

Summary. When semen is collected from boars 30 min after a single injection of 25 to 50 mg atropine sulphate, the volume of the ejaculate is reduced to about one-fourth, and hardly any gel is present. The ejaculate from an atropine-treated boar has less chloride, but a higher concentration of spermatozoa, organically-bound acid-soluble phosphate, fructose, ergothioneine, and citric acid, than normal semen. These changes are thought to be due to the inhibiting action of atropine on the parasympathetic stimuli which normally reach the urethral and bulbo-urethral glands at the time of ejaculation. In consequence, the urethral glands no longer contribute the watery, chloride-rich fluid, and the bulbo-urethral glands fail to provide the gel. Atropine does not interfere either with epididymal function, in so far as the output of spermatozoa and acid-soluble phosphate (mainly glycerylphosphorylcholine) is concerned, or with the secretory output of fructose, ergothioneine and citric acid, by the seminal vesicles. Thus, being made up to a large extent by the epididymal and vesicular contributions, the semen voided by the atropine-treated animal resembles the so-called spermrich or middle portion of a normal ejaculate.