Summary
Rat studies suggest that deficiency in pantothenic acid (vitamin B5) can reduce testosterone levels and sperm motility. Its effects may be primarily in the testes. Unfortunately, human studies are lacking.
Animal Studies: Pantothenic Acid deficiency lowers testosterone
Rat study: Pantothenic acid deficiency lowers, testosterone and sperm motility, but leaves LH and FSH unchanged
https://www.ncbi.nlm.nih.gov/pubmed/19959891
- The decrease in testosterone occurred without a change in the level of luteinizing hormone (LH), suggesting that pantothenic acid has an effect mainly in the testes.
- However, this cannot be the whole story as, all else being equal, a reduction in testosterone from the testes will lead to increased LH due to reduced negative feedback on the pituitary.
- The researchers speculate this may have something to do with the reduction in corticosterone that was also noted. Corticosterone has an inhibitory effect on corticotrophinreleasing hormone (CRH), and CRH has an inhibitory effect of GnRH release from the hypothalamus. Lowering corticosterone may therefore lead to decreased GnRH release. Reduced GnRH depresses LH production, balancing out the expected increased production from lower testosterone levels.
Rat study: Testicular changes occur in pantothenic acid deprived rats
https://www.cabdirect.org/cabdirect/abstract/19591405490
Given that I'm unable to access the full text, I'm not sure what these changes were, but presumably they were negative.
Rat study: Excessive panthothenic acid leads to decrease in body weight, including testes
https://www.ncbi.nlm.nih.gov/pubmed/16521696
Rats study: Pantothenic acid supplementation increases the basal levels of corticosterone and progesterone in male rat adrenal cells
http://ci.nii.ac.jp/naid/110006684341/
http://jn.nutrition.org/content/66/4/457.extract