, 'Endocrinology of Protochordates' by Sherwood:      http://pubs.nrc-cnrc.gc.ca/rp/rppdf/z04-178.pdf, Cross references:   Hormones in General Amphioxus Amphioxus Receptors Lamellar Body = Pineal Gland   
Amphioxus Pituitary Amphioxus Oxytocin Amphioxus Gonads Amphioxus Stress Hormones Lamprey Hormones Shark Hormones Teleost Hormones Human Endocrinology in General  Amphioxus, a Primitive Chordate, Is on Steroids: Evidence for Sex Steroids  (Goog). 
http://endo.endojournals.org/cgi/content/full/148/8/3551
Full length article available online.  I wasn't able to print the PDF.   
I was surprised.  Although the HOX genes are present in the fruit fly, amphioxus and humans, the endocrine system is not as broadly universal.  As of 2007, there are indications that the sex steriods are present and active in amphioxus, this was not unequivocally determined.  However, the estrogen receptor, the progesterone receptor (PR), the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR), and the androgen receptor (AR) were all identified and sequenced. 


The amphioxus genome illuminates vertebrate origins and cephalochordate biology  (PubMed) 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493399/  
"The primary vertebrate endocrine organs (pineal gland, ovary, testis, endostyle/thyroid, brain, gut, and pituitary) have structurally simpler homologs in amphioxus." 

Amphioxus Hormones
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