Effect of injecting 5-methoxy indoles, pineal compounds, on testicular weight of white leghorn cockerels (Gallus domesticus L.).

White leghorn cockerels of the same age with combs of about equal size and raised under identical conditions were injected with melatonin, 5-methoxytryptophol, or with 5-methoxytryptophol in combination with melatonin. Melatonin, injected in animals with small comb sizes, has no effect on testicular growth, whereas an inhibiting effect is noticed in animals with larger comb sizes. The 5-methoxytryptophol treated animals demonstrated stimulated testicular growth, which can be interpreted as an acceleration of the rhythm of growth. The stimulatory effect on testicular growth is more distinct if 5-methoxytryptophol is injected in combination with melatonin.