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21 Cards in this Set
- Front
- Back
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Three hormones from anterior pituitary reg reproductive func, sex development and sex characteristics
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1. prolactin
2. Lutenizing hormone lh 3. Follicle stimulating hormone |
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Prolactin
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- produce milk secretion and maternal behavior
- polypeptide similar to GH - levels lower in males than females rise in pregnancy and reach max at delivery - syn in lactotrope cells |
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Lutenizing hormone
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Females: stimulate ovulation
Males: stimulate testosterone secretion Syn in gonadotrope cells |
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Follicle stimulating hormone (FSH)
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Females: stimulates ovarian follicle growth
Males: stimulate spermatogenesis |
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Regulation of prolactin release
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- sucking by infant -> prolactin release, mediated by neural input to the pituitary
- visual cues from babies not belonging to mom trigger release - exercise hypoglycemia, stress - prolactin is pulsatile with avg levels --> circadian rhythm - unclear whether physiolocially relevant hypothalamic prolactin releasing factor |
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Dominant regulation of prolactin release is
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via negative control provided by dopamine neurons of the arcuate hypothalamus which release dopamine into the portal system
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Dopamine binds to...
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D2 dopamine receptor on lactotropes which inhbits cAMP through Gi mediated inhbition of adenylate cyclase
induces hyperpolarization and blockade of Ca channels and calcium dependent exocytosis inhibiting prolactin release |
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1. High levels of estrogen
2. Moderate levels of estrogen |
1. inhibit prolactin release via negative feedback loop
2. facilitate prolactin syn and release prolactin--> supresses GnRH , estrogen level and libido, lactation promotes prolactin relase post partum helps delay subsequent pregnancy |
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Regulation of LH and FSH release
Gonadotropin- releasing hormone (GNRH) |
- decapeptide hormone from hypothalamus
- positive signal promoting release of LH and FSH--> gonadal function - activin, inhbin, follistatin provide both neg and pos feedback singals regulating release |
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Regulation of LH and FSH release
Prolactin |
- abundant in breast
- activated by GH - occupation of prolactin alters gene transcription and protein translation --> stimulate growth and differnetiation of breast epithelium --> lactation - prolactin --> inc production of 1,25 (OH2)- vit D inc Ca absorption from the gut and mobilization from bone, --> inc ca available for fetus |
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Hyperprolactinemia
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- can result from osteoporosis
- results form prolactinoma (common pituitary tumor) - depress estorgen levels leading to infertility in women with amenorrhea, galactorrhea, and hypogonadism Men: can lead to impotence, infertility and inc in breast size may result from primary hypothyroidism (high TRH levels) or antpsychotic treatement with dopamine receptor antagonist |
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Hypoprolactinemia
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- result form pituitary damage --> results in failure to lactate
- no therapeutic prolactin preparation |
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Treatment of hyperprolactinemia
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- dopamine agonist acting on the D2 dopamine receptor of the lactotrope
- most common bromocriptine |
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Treatment of hyperprolactinemia
Cabergoline |
dopamine agonist with longer half life
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Posterior pituitary hormone--> secretes two major nonapeptide hormones
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- synthesized in hypothalamus travel to posterior pituitary via hypothalamic nerves
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ADH antidiuretic hormone aka vasopressin
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OVLT and adj hypothalamic areas sense osmolality of plasma
Inc in osmolality send singals to supraoptic and paraventricular hypothalamic nuclei to release ADH from porjections to the posterior pituitary - CNS input from sensing blood volume and P also regulates its release |
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ADH
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acts on kidney to retain water and prevent furhter inc in osmolality
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Central diabetes insipidus
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caused by failure to secreted ADH
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Nephrogenic diabetes insipidus
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caused by failure of kidney to respond to ADH
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syndrom of inappropriate ADH
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tumors secret ADH
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Oxytocin
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acts on breast to eject milk and on the uterus to cause contractions
released by suckling, sensory input indicating the presece of an infant, dilation of the cervis during labor and orgasm |
