As you may have noticed, I have an ever-growing hunger for words. Actually, I hunger for knowledge of all sorts of types. Come to think of it, I hunger for food too… fortunately, I exercise, and have gotten better at eating less. Otherwise not just my knowledge but my weight and waistline would be growing.
Interestingly, there is something of a biochemical connection between, on the one hand, physical hunger and growth and, on the other hand, learning and memory. The link is something that demonstrates yet again that – as you may have observed in my note on Suzanniwana – scientists also often have a deep-rooted love for language. The link, you see, has a name that is radically original: ghrelin.
What is ghrelin? It’s a peptide that serves a few functions in the body. It is associated with hunger – it increases before eating and decreases after – and it also appears (based on animal studies) to stimulate learning and memory via the hippocampus, which suggests that you may learn better on an empty stomach. In fetuses, it seems to promote growth. Higher levels of it are also associated with short sleep duration and obesity – if you don’t get enough sleep, you are hungrier and get fatter. (Which means my frequent late nights writing word tasting notes aren’t helping my weight.) I don’t know how one resolves the apparent conflicting issue that short sleep is not generally associated with learning and memory.
And where does ghrelin get its name? Perhaps from those gremlins that chase around in your stomach – or in your head? Or the sound of your stomach growling? Maybe from the fact that if you turn LI into U, GHRELIN is an anagram of HUNGER? No, it comes from an original root – I already told you it was radically original. The hormone is associated with growth; it is a growth-hormone-releasing peptide. As it happens, the Proto-Indo-European (PIE) root related to “growth” is ghre. (What is Proto-Indo-European? It’s the reconstructed ancestor of the Indo-European languages, spoken roughly 6000 years ago. The language family has grown considerably since then, and our knowledge of it is still growing.) It’s a nice coincidence that ghre also looks like an acronym for growth-hormone-releasing. And the lin? A common suffix for hormones.
How do you pronounce it? Don’t bother trying to make a voiced aspirated velar stop at the beginning, and don’t linger on h – just treat the h as silent for the purposes of Modern English. And as you roll the idea of this hormone around in your mind, and as the hunger created by your brain use starts your stomach up, roll this word around in your mouth – a nice piece of PIE.