This kindGonadotropinThe function of will be introduced in the chapter of target gland function, this section only introducesauxinandProlactinIts physiological function and secretion regulation.
Growth hormone (GH)
Human GH is a polypeptide containing 191 amino acids, and its structure is similar toPRLIt is similar, so it has cross effect with PRL.The chemical structure and immune characteristics of GH in different animals are quite different.Except monkeys, GH of other animals is invalid for humans.
The main function of GH is to promote the growth and development of the whole body.This is because on the one hand, it promotes the growth of bones, making people tall, and on the other hand, it promotesprotein synthesisTo develop muscles.When the pituitary gland is removed when the animal is young, the animal stops growing. If GH can be supplemented in time, the animal can still recover its growth.Clinically, children who lack GH due to congenital pituitary damage are short in stature but normal in intelligenceDwarfism。The proportion of upper and lower body length of such patients is basically similar to that of normal people.On the contrary, if GH is secreted too much in childhood, the body will grow too tall and formGigantism；If GH secretes too much in adulthood, it will stimulate the limb bone andFacial boneHyperplasiaAcromegaly。The internal organs of such patients, such as liver and kidney, are also excessively enlarged.It can be seen that an appropriate amount of GH plays an important role in maintaining the normal growth of the body.The fasting blood GH content of normal people is below 5ng/ml.
The mechanism of GH promoting bone growth has been preliminarily clarified: under the effect of GH, it is mainly produced by the liverAuxin medium, which acts oncartilage, Accelerationcartilage cellsprotein synthesisIncrease cartilage collagen tissue, promote chondrocyte division, and make cartilage grow. After ossification, cartilage becomes bone.GH pairHepatocyte、skeletal muscleCells andFibroblastIt also has similar effects, but has no effect on the growth and development of the brain.
Another important role of GH is to participate inIntermediate metabolismandenergy metabolismAdjustment of.Experiments have proved that its role in this respect is independent of auxin medium.GH promotes protein synthesis by accelerating the synthesis of DNA and RNA.It can also promote fat decomposition and supply energy, thus reducing tissue fat, especially body fat.On the one hand, these functions are conducive to the growth and repair of the body, and on the other hand, they keep the metabolism of the body "young", that is, the body is rich in protein and body fluid, but less in fat.GH pairCarbohydrate metabolismThe effect of GH is complex, and physiological level of GH can stimulateIslets of langerhansBeta cellsecretioninsulinIndirectly strengthen the utilization of glucose.In short, GH can promoteprotein synthesis, accelerate fat decomposition, strengthen the rational use of sugar, and shift energy from sugar to lipid.The GH content in the blood of adults and the elderly remains at a certain concentration, which is closely related to the regulation of metabolism and is an important factor for the body to adapt to the environment.
Secretory receptor of GHhypothalamusDual regulation of GHRH and GHRIH.In addition, GH secretion is also affected by sleep, blood sugar and amino acid content and other factors.During stress, GH secretion also increases.
Prolactin (PRL)
PRLIt is a peptide containing 199 amino acids and is a hormone with wide functions. Its main functions are briefly described.
PRL can promotebreastGrowth and development, cause and maintain mammary gland secretion.In female adolescence, the development of mammary gland is mainly caused by sex hormones and other hormonesSynergy。gestationTime PRL vsChorionauxin、estrogenAnd progesterone to further promote breast developmentlactationThe condition is gradually mature, but it does not secrete milk. After delivery, PRL will play the role of initiating and maintaining breast secretion.The research also shows that PRL also has effects on pig, monkey and human ovaries, and can directly affect the luteal function.It increases the synthesis of progesterone and reduces the decomposition of progesterone through its effect on LH receptor, thus strengtheningCorpus luteumFunction of.
PRL is also subject tohypothalamusDual control.ProlactinRelease factorPromote its secretion;Prolactin release inhibitory factor inhibits its secretion, and it is believed that the latter is often dominant.A baby sucks its motherpapillaStimulate the nipple whenSensory nerve endings, the impulse is transmitted to the hypothalamus to promote the secretion of prolactin releasing factor, and thenPRLSecretion.PRL secretion decreased or stopped after the stimulation stopped.This is a typicalNeuroendocrineReflection.The study found thatStress statePRL is often associated withACTHAnd GH secretion increase simultaneously,stressAfter the stimulation stopped, all three gradually returned to normal levels.The function of PRL in stress is not clear.
The neurohypophysis releases two hormones, vasopressin (VP) or antiDiuresis(ADH) andOxytocin（OXT）。Both are 9 peptides, and their molecular structures are similar.Their physiological functions also overlap.
Vasopressin (VP)
The physiological function and secretion regulation of VP have been described in this bookThe blood circulatory systemandurinary systemIt is introduced in relevant chapters and paragraphs, and will not be repeated here.
OXT to uterussmooth muscleThe role ofSpeciesThe effect is different between the animals without pregnancy and the pregnant uterus.If the uterus is not sensitive to it,gestationThe uterus is more sensitive to it.estrogenIt can increase the sensitivity of uterus to OXT, while progesterone has the opposite effect.Although there have been many studies on the role of OXT in delivery, the physiological significance of OXT in the process of delivery and postpartum hemostasis has not been determined.Clinically, use OXT after delivery touterusIntense contraction to reduce postpartum bleeding, but the dosage used has exceeded the physiological rangePharmacological effect。
Hypophysis
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Hypohypopituitarism (Simon Sheehan syndrome) is a group of diseases that cause damage to the anterior lobe of the pituitary gland due to a variety of reasons, resulting in secondary hypofunction of the gonad, thyroid and adrenal cortex, and resulting in corresponding symptoms.Postpartum hemorrhage、Pituitary tumor, infection, surgical trauma, etc. can cause hypophysis dysfunction. Generally, the onset of the disease is slow, and patients often have gonadal atrophy first, followed by hypothyroidism and adrenal dysfunction.In severe cases, hypoglycemia, coma and shock may occur.This disease belongs to the category of "deficiency and fatigue" in traditional Chinese medicine, and the treatment mainly focuses on warming and tonifying the spleen and kidney.
[Diagnostic points]
Clinical manifestations: (1) hypogonadism syndrome group: insufficient gonadotropins (FSH, LH) and abnormal secretion of prolactin (PRL) lead to: postpartum galactorrhea, breast atrophy, long-term amenorrhea, decreased sexual desire until disappearance, genital atrophy, etc.
(2) Hypothyroidism syndrome group: insufficient thyroid stimulating hormone (TSH) leads to: chills, obesity, dry and rough skin, pale, less shiny, less sweating, less elasticity, serious myxedema, anorexia, depression, apathy, etc.
(3) Adrenocortical hypofunction syndrome group: insufficient adrenocorticotropic hormone (ACTH) leads to extreme fatigue, physical weakness, anorexia, nausea and vomiting, weight loss, low resistance, easy infection, slow heart rate, weak pulse, low blood pressure, and hypoglycemia in severe cases.
(4) Tumor compression syndrome group of adenohypophysis or its vicinity: the most common and serious cases are headache and cross injury of optic nerve, resulting in hemianopsia or even blindness.Sometimes there may be hypothalamic syndrome and intracranial hypertension syndrome caused by brain tumors.
Adenohypophyseal cell
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A general term for various hormones secreted by pituitary cells.There are many kinds of pituitary cells that secrete their own hormones.Auxin cells (also called α cells) secrete growth hormone;Prolactin cells (also called epsilon cells) secrete prolactin;Thyroid stimulating hormone cells (also called β 2 cells or θ cells) secrete thyroid stimulating hormone;The adrenocorticotropic hormone cells (also called β 1 cells) secrete adrenocorticotropic hormone, melanocyte stimulating hormone and lipotropic hormone;Gonadotropin cells (also called delta cells) secrete luteinizing hormone and follicle stimulating hormone.The endocrine function of the adenohypophysis is mainly controlled by the signals sent by the hypothalamic nerve cells.Hormones secreted by some nerve cells in the hypothalamus (see "hypothalamic hormone") are transported to the adenohypophysis through the pituitary portal system and control the secretion of adenohypophysis hormones.
