There basically no evidence for dmt being synthesized and/or secreted from the pineal gland. A search in Pubmed (the most complete repository of scientific publications in medical, biomedical and biological sciences) for "pineal AND dmt" yields no results. So, the jury is still out there.

There are references of course that the pineal gland expresses the enzymes that can potentially synthesize dmt but this is NOT a proof that it actually synthesizes it. The biological systems tend to be somewhat conservative and in many cases and they may use the very same enzymes in somewhat similar pathways to synthesize different compounds. By that I mean that the enzymes that are present and could possibly be synthesizing dmt (given tryptamine as a substrate) in the pineal might be very well used for synthesizing something else (for instance, mono-methyl tryptamine, which has yet not very well investigated activities).

But then, if pineal is synthesizing and excreting dmt at special times how can we detect it? Which are those special times? How can we know before butchering some human brains and check their pineals? Mind you, plenty of folk will find it a bit unethical.

As an analogy of the above scenario, women secrete the hormone hCG in their blood and urine only when they are pregnant (this is what the pregnancy test detects) or post-menopausal. The woman carries most of the enzymes for synthesizing hCG, but it is in pregnancy (or after menopause) that she actually produces it.

So, if anyone tells you that dmt is synthesized and secreted by the pineal gland feel free to answer:

"We do not have any scientific proof yet. It may or it may not. And there is no more or less evidence in favor of either case."