ghrelin, growth hormone, and IGF-1

ghrelin

GH release, food intake, energy and glucose homeostasis, cell proliferation and differentiation are a function of this hormone. Further, this Yale study reveals that ghrelin has a positive influence on learning and memory processes, and cognitive enhancing effects of ghrelin have also been reported.

At the same time, ghrelin stimulates appetite and adiposity in animals as shown here, where fasting increases ghrelin, and re-feeding reduces ghrelin. This indicates that ghrelin is a leptin antagonist.

Ingested medium-chain fatty acids are directly utilized for the acyl modification of ghrelin discusses that GH release is a function of ghrelin and reports results that

indicate ingested medium-chain fatty acids are directly used for the acylation of ghrelin.

Significance of ghrelin acylation

This article explains that ghrelin is activated by growth hormone secretagogue receptor GHSR-1a. According to Entrez Gene, GHSR-1a is the receptor for ghrelin and defines a neuroendocrine pathway for growth hormone release.

Ghrelin acylation is absolutely required for both GHSR-1a binding and its central endocrine activities

There is an unacylated form of ghrelin, des-acyl ghrelin, which does not bind GHSR-1a and has no endocrine activity.

So it appears as though acylation of ghrelin is required for it to exert effects such as growth hormone release.


growth hormone (GH)

With this information on how MCFA relates to ghrelin relates to growth hormone, this study on MCFA effects on GH now makes more sense.