Biphasic Response of anti stress hormones. If a stressing stimulus takes place there will be a dysphasic response of certain hormones. This can be observed in the GH (growth hormone), testosterone and pro-lactines (related to maternal milk and reproduction as a whole). This biphasic response is a risen response to a stress which afterwards lowers below basal, normal levels.
Pro-lactines: reacting to a stressing stimulus rises much, but when facing a chronic stress diminishes below basal levels thus producing amenorrhea or anovulatory periods.
GH: rises when facing an acute stress but soon diminishes reaching lower basal levels. Children who undergo stress face retarding growth problems.
Testosterone: acute rise and afterwards, diminution below basal levels. It is similar to pro-lactines. Inhibition of gonad axis during chronic stress. We said that testosterone was related to aggression levels. Fast initial rise is related to high aggression levels. Both men and women experience this condition.
Hyper tensor Response
Stress will be hypo tensor. And response to stress will be hyper tensor. Adrenalectomized animals submitted to stressing stimuli will not be able to respond to these stimuli, they will not be able to give an adaptation response. Thus they will die from hypotension and hypoglycemia. In reality hyper tension and the rise of glucemia are adaptation responses to stress, compensating responses. By itself, stress is hypo tensor and hypo glucemiant. If response to stress does not take place, death does.
This hyper tensor response can be observed in the cardiovascular system. A rise of the five cardiac properties will take place (volume minute, volemia, vessel tension, hyper tension, they all, will rise). Vessels will constrict and a blood flow rise will take place in the heart, the brain and the muscle. Blood flow will diminish in the digestive, gonad, skin. This happens because of a sympathetic stimulation and the Para sympathetic inhibition. Flow does not only increase in the muscle, contraction-relaxation’s rise will produce muscular vessels contractility. Venous return (VN) to heart will increase. Pre-charge (how much blood the heart receives), therefore, will rise. The more it receives, the more it will eject. Higher will be the expulsion and the volume minute. Thus, volemia and arterial pressure rise.
Response in the kidney
Sympathetic response in the kidney will be the contraction of the afferent arteriole. Renal plasmatic flow (amount of blood which reaches the glomerular capillary), consequently, will diminish. Glomerular filtration’ volume will then diminish. This is why excretion lowers, volemia rises and so does arterial pressure. If this response is exacerbated during chronic stress left ventricle’s hypertrophy and arteriosclerosis will take place. Heart stroke, ischemia and death are almost inevitable.
Gastrointestinal Response
There will be a blood flow and acid secretion (stomach) inhibition. Therefore, hunger will diminish. Motility and transit within the thin intestine also diminish. Inside the colon (thick intestine) will be stimulated and the same will happen with defecation. During acute stress this function might as well be inhibited. And the same happens with urinary activity. This is also an indicator of this type of biphasic response.
Immunity
We already know that it is an immune-depressive effect. It is produced by the immune-depressive hormones’ rise (A, NA and cortisol), and a diminution of the immune-stimulating hormones (GH and pro-lactines). These hormones which should be ensuring our defenses are below basal levels. If we are stressed, therefore, we are exposed to immune deficient pathologies.
There exist three important signal molecules in the immune system: IL-1, IL-6 and Tumor Necrosis Factor.
Reproduction
In dancers or in athletes undergoing intense exercise, even in individuals who develop intense work, might suffer from gonad axis depression. In women is clearer, there is amenorrhea, anovulatory cycles, puberty delay or even a backward process in maturation (loss in mammary system development or loss of their secondary sexual characteristics with teen age resemblances). Men might suffer infertility.
Gonad Axis
LHRH: gonad atropine liberating hormone.
LH: luteinizant hormone (gonad atropine)
FSH: follicle-stimulant hormone (gonad atropine)
PRL: pro lactines (gonad axis stimulating hormone)
Hypothalamus regulates the gonad axis (reproductive action). It liberates a LHRH hormone which will stimulate gonad atropine liberation (LH and FSH). Gonad atropines will stimulate gonad tropism (ovary and testicle), they feed them, keep them. These hormones will keep the ovary active. FSH will influence the menstrual cycle first stage where follicles with ovaries will develop. These follicles are stimulated to favor ovulation. Once ovulation appears, the follicle frees that ovule and what is left is called lute or yellow body. This body will produce progesterone and will become the hormonal support for the baby during pregnancy. LH will appear at a second stage.
Estrogens and progesterone will be produced in the ovary. Androgens, among them testosterone, will be produced in men. We find these same hormones in men, but they carry on other functions. Ovary is replaced by testicle. The axis is the same, but functions will be different.
Hypothalamus liberates CRH. Hypofisis frees ACTH. Suprerenal Cx liberates cortisol. Cortisol directly inhibits the ovary. It will inhibit LH and FSH receptors. At the same time it inhibits the hypofisis in the nuclei destined to produce pro-lactine which stimulates the gonad axis. CRH will inhibit the hypothalamic nuclei which will free LHRH. Thus, gonad atropines themselves will be inhibited.
Nociseption
There is an analgesic theory of stress. It is linked to the fleeing and fighting response. Mechanisms are polemic. Clearly defined molecules do not exist. It is thought that there could be inhibition in the central level descendent ducts which inhibit the nociceptive ways. However, this is still a theory. Some signal molecules might exist.
Psychological state
Acute stress is linked with high anxiety levels and chronic stress, with depression. .
Stress will be hypo tensor. And response to stress will be hyper tensor. Adrenalectomized animals submitted to stressing stimuli will not be able to respond to these stimuli, they will not be able to give an adaptation response. Thus they will die from hypotension and hypoglycemia. In reality hyper tension and the rise of glucemia are adaptation responses to stress, compensating responses. By itself, stress is hypo tensor and hypo glucemiant. If response to stress does not take place, death does. 
