Erm... I'm not a medical doctor, and I really have no clue what affects the amount of semen which a male ejaculates... but I do
know that sperm/semen is not stored in the prostate gland. Sperm is stored in the Epididymis
prior to its entrance into the vas deferens
during sexual arousal, which subsequently combines with the fluids secreted by the seminal vesicles
, and then exits the vas deferens
into the urethra. Once the sperm and fluids from the seminal vesicles
combine, however, they do travel through
the prostate gland
into the Urethra.
From: Cleveland Clinic Health System
Epididymis — The epididymis is a long, coiled tube that rests on the backside of each testicle. It functions in the transport and storage of the sperm cells that are produced in the testes. It also is the job of the epididymis to bring the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens.
Just trying to avoid any possible confusion about how the male reproductive system works.