Kisspeptin was discovered in Hershey, Pennsylvania, and was named after Hershey’s Kisses. It has 776 pubmed citations going back to 2001, and may (or may not) play a key part integrating circannual reproduction patterns and seasonal thyroid function.
Kisspeptin was originally identified as a protein that inhibited breast cancer and melanoma. This might also provide insight into the WHO’s recent declaration of shift work as a “probable” carcinogen.
Exhibit A. TSH restores a summer phenotype in photoinhibited mammals via the RF-amides RFRP3 and kisspeptin (Klosen 2013)
In this study, TSH infusion in short-day adapted hamsters (who are in winter non-breeding mode) induced summer phenotype & kisspeptin. It also fattened them up a bit. These TSH secreting neurons express melatonin receptors, but not those for TRH or T3 (Klosen 2002), so it is said to go something like this: