Introduction
Numerous hormones, including the hypothalamic neuropeptides, act as neurotransmitters and neuromodulators in the central nervous system, are involved in the physiologic regulation of breathing, and may participate in breathing disease. In addition to the central effects, a few hormones also control breathing at the peripheral chemoreceptors or may have local effects on the airways and lungs. Progesterone and estrogen protect from sleep-disordered breathing anywhere testosterone may predispose to it. Thyroxine and progesterone are known to stimulate respiration. Recently, several hormones, such as corticotropin-releasing hormone and leptin, have been suggested to act as respiratory stimulants.
Dopamine, neuropeptide Y, and somatostatin have a depressing effect on breathing. A few animal models and experimental human studies suggest many hormones may be involved in respiratory control. There is growing evidence that hormones have a significant impact on most biological systems, including the control of breathing. Two broad classes of hormones involved in the neuronal control of breathing are stress hormones and sex hormones. The majority of the hormones include steroids, a striking feature in both groups that are derived from cholesterol. Stress hormones include many peptides that are primarily produced from the paraventricular nucleus of the hypothalamus, and they are secreted into the brain or to the circulatory system.
What Are the Hormones Involved in Breathing?
Hormones that affect breathing include the following, which are listed below:
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Growth Hormone: Growth hormone-releasing hormones increase; meanwhile, somatostatin decreases the secretion of the growth hormone. Growth hormone-releasing hormones are a common physiological factor that stimulates growth hormone release and slow-wave sleep. Growth hormone secretion is based on gender, age, menstrual cycle phase, sleep quality, nutritional state, physical exercise, and body composition. Visceral fat has a powerful effect negatively on growth hormone secretion.
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Reproductive Hormones: Progesterone is a powerful respiratory stimulant with the role of other reproductive hormones in controlling breathing. Multiple locations of estrogen, progesterone, prolactin, androgen, and human gonadotropin/ or the luteinizing hormone receptors may act locally in various tissues, including lungs, trachea, brainstem, and brain. Thereby they are possibly involved in breathing.
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Corticotropin - Releasing Hormone: Corticotropin-releasing, also called corticotropin-releasing factor, is the counter regulator of growth hormone releasing hormone/corticotropin-releasing hormone ratio that changes in favor of the corticotropin-releasing hormone. Corticotropin-releasing hormone receptors are widely distributed in the areas of the brain that control breathing. Therefore, the corticotropin-releasing hormone acts as a respiratory-releasing center stimulant in healthy men and patients with respiratory failure. That increases the tidal volume and respiratory rate throughout a time interval for a few minutes, which increases the oxygen in the blood.
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Thyroid Hormones: The importance of thyroid hormones for breathing is demonstrated by respiratory changes that accompany conditions with the altered functions of the thyroid. Hypothyroidism is characterized by hypoventilation, where hyperventilation and dyspnea are the signs of hyperthyroidism. The ventilatory responses for hypercapnia and hypoxia decrease in the case of hypothyroidism and increase in the case of hyperthyroidism. Effects of high or low serum levels of triiodothyronine is seen on respiration.
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Epinephrine and Norepinephrine: Sleep onset may be associated with a decrease in circulating concentration of epinephrine and norepinephrine, with nocturnal occurring at approximately one hour of sleep, in contrast with the daytime and nocturnal urinary non-epinephrine levels as well as both the day and night time. Plasma norepinephrine concentrations were increased or within the normal limits in the patients with severity and during sleep.
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Leptin: Leptin is a peptide that is produced by adipose tissue. The strongest predictor of serum leptin concentration accounts for variance in leptin levels. In mice, adipose tissue leptin receptors have been found in the brain, heart, lungs, kidneys, liver, ovaries, and testes. Leptin may play an important role in regulating the energy balance, but it has recently also been linked with control of breathing.
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Respiratory and Cardiovascular Systems: Stress hormones may affect one's respiratory and cardiovascular systems. During the stress responses, the breathing gets faster to distribute the oxygen-rich blood to the body quickly. Stress can make breathing even harder if one already has breathing problems such as emphysema and asthma. Under stress, one's heart also pumps faster. The stress hormones may cause the blood vessels to constrict and may divert more oxygen for the muscles, so one has more strength for taking action. This may also raise blood pressure. As a result of chronic or frequent stress, one's heart works too hard for too long and it results in increased blood pressure and the risk of having a stroke or heart attack.
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Vasopressin Release and Respiration: Some evidence shows that vasopressinergic neurons increase arginine vasopressin levels and affect respiratory activity. The release of arginine vasopressin and changes in respiration in responses to these stimuli were coincidental, or there is a functional relationship between arginine vasopressin and regulation of the respiratory system. Increased release of the arginine vasopressin and its surrogate copeptin under medical conditions accompanied by respiratory disturbances. It is analyzed as evidence of arginine vasopressin's involvement in regulating the respiratory system.
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Sex Steroid Hormones and Neural Control of Breathing: Sex steroid hormones, including estrogen, testosterone, and progesterone, are involved in the central neural control of breathing. Sex hormones may show their effects on the respiratory motor neurons through neuromodulators, particularly the serotonergic system. Some studies have shown that the serotonin levels in the phrenic and hypoglossal nuclei were greater in females than in male rats. Serotonin-dependent plasticity in the hypoglossal and phrenic motor output also differs in female and male rats. The changing levels of the gonadal hormones throughout the estrous cycle that coincide with the changing levels of 5HT in the respiratory motor nuclei and gonadectomy in the male rats may decrease 5HT-dependent plasticity in respiratory motor output. Speculate sex steroid hormones are critically involved in adaptations to neural control of breathing throughout life. Decreasing levels of these hormones that are critically involved in adaptations in the neural control of breathing throughout life and decreasing these hormones with increasing age can negatively influence the respiratory control system.
Conclusion
Numerous hormones are involved in the process of controlling breathing. The role of female hormones is supported by the distribution of hormone receptors and may increase sleep-disordered breathing after menopause. Hypothyroid patients show decreased ventilatory chemosensitivity, which improved with thyroxine replacement therapy.
