Lamprey Cortisol, etc.

Cross references:  Lamprey Hormones     Lamprey Neuromodulators
Lamprey Neuropeptides    

Absence of known corticosteroids in blood of river lampreys (Goog) 
Only abstract available online. 
Serum of adult female river lampreys contained less than 3 ng/100 ml of cortisol, 11-deoxycortisol, and corticosterone, and less than 5 ng/100 ml of cortisone even after repeated injections of corticotropin.

Mineralocorticoid (Wiki)   
"Mineralocorticoids are a class of steroid hormones characterised by their similarity to aldosterone and their influence on salt and water balances.
"  "The primary endogenous mineralocorticoid is aldosterone, although a number of other endogenous hormones (including progesterone and deoxycorticosterone) have mineralocorticoid function.

Co-Evolution of Steroidogenic and Steroid-Inactivating Enzymes and Adrenal and Sex Steroid Receptors  
Very technical full length article available online.   
    "The adrenal and sex steroids - aldosterone, cortisol, estradiol, progesterone and testosterone - regulate a wide range of physiological processes in vertebrates including reproduction, development and homeostasis." 
    "Receptors for the adrenal and sex steroids arose by a series of gene duplications from an ancestral nuclear receptor in a primitive vertebrate, at least 540 million years ago. ... The estrogen receptor (ER) appears to be the ancestral steroid receptor." 
    "... steroid receptors, steroidogenic enzymes and steroid-inactivating enzymes arose at about the same time in primitive vertebrates, and the subsequent co-evolution of these proteins was important in the evolution of complex developmental pathways found in vertebrates" 
    "Recent work from lamprey, a jawless fish, and Ciona intestinalis, a urochordate, further narrows the timing of origins of adrenal and sex steroid receptors. Thornton (2001) found an ancestral estrogen receptor (ER), progesterone receptor (PR) and corticoid receptor (CR) in the lamprey, a jawless fish. An analysis of the recently completed genome of Ciona indicates that this organism does not have receptors for adrenal and sex steroids (Dehal et al. 2002; Baker, 2003). Together these analyses suggest that adrenal and sex steroid receptors arose in a cephalochordate, such as amphioxus, or in a jawless fish." 
    "Thornton (2001) proposed a novel mechanism that explains how the first steroid receptor was the ER and responded to estrogens, despite the presence of progestins, glucocorticoids and androgens. He proposed that the upstream steroids, such as progesterone, cortisol, testosterone were inactive because a receptor with a ligand-binding domain for these steroids had not yet evolved. The presence of these upstream “orphan” ligands was a selective force for the evolution in duplicated receptors of a new steroid binding activity."  

Stress Hormone Discovered In 500 Million Year Old Fish
Short article in plain English. 
A University of British Columbia zoologist has discovered a new corticosteroid hormone ...
called 11-deoxycortisol – in the sea lamprey that plays dual roles in balancing ions and regulating stresses, similar to aldosterone and cortisol in humans. ...The origin of the corticosteroid signaling pathway has remained controversial over the past several decades because the identity of the ancestral corticosteroid has been elusive.

MSU sea lamprey research sheds light on how stress hormones evolved 
Short article in plain English. 
     "By identifying 11-deoxycortisol as a stress hormone in lamprey, it allows us to better understand how the endocrine system in vertebrates evolved into the complex systems we see in humans today ...    The hormone is the only one the researchers have found so far in the lamprey and ... the researchers are hypothesizing that it may be the only corticosteroid hormone in the lamprey.  Humans, in contrast, have more than 30 corticosteroid hormones. 

11-Deoxycortisol (Wiki) 

"11-Deoxycortisol (or cortodoxone) is a steroid, and an immediate precursor to the production of cortisol. It functions as a mineralocorticoid, though is less potent than cortisol.

Lamprey Cortisol 
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