ESPE Yearbook of Paediatric Endocrinology

Nature. 2022;602(7898):632-8. doi: 10.1038/s41586-022-04408-7.PubMed ID: 35140404

Brief summary: This study in the fruit-fly, Drosophila melanogaster, identified a novel gut-derived, nutrient-specific neuropeptide hormone, ‘Diuretic hormone 31’ (Dh31), which triggers the insects to switch their behaviour from feeding to courtship and reproduction.

Romantic dinners are ingrained in human culture as an essential component of courtship, love and relationships. However, I think few of us suspected that this behaviour is based on a direct physiological connection!

The authors found that protein-rich foods triggered the release of Dh31 from enteroendocrine cells in the gastrointestinal tract. Unsurprisingly, starved males prioritized feeding behaviours above courtship. However, remarkably after consumption of protein-rich food this behaviour rapidly changed within only a few minutes. They used functional imaging and optogenetic stimulation to show that circulating Dh31 rapidly excites brain neurons that express the Dh31 receptor (Dh31R). They identified two distinct populations of Dh31R+ neurons in the brain; stimulation of one population inhibited feeding through allatostatin-C, and the other population triggered courtship through corazonin.

It seems amazing that a single molecule can have such a marked influence on behaviour. Courtship in these flies includes a complex array of behaviours, including performing a courtship song to entice females, through to reproductive activity. The authors draw parallels with other hormones that alter our behaviours: orexin on the switch from awake to sleep, leptin on the switch from hungry to feeling full, and possibly also prolactin on promoting warm relational connections with others.