Endocrine IV

Flashcard 1

Front: What is the parent molecule of the melanocortin system? Back: Proopiomelanocortin (POMC)

Flashcard 2

Front: Name four posttranslational peptides derived from POMC that are part of the melanocortin system. Back: Melanocyte-stimulating hormones (α-MSH, β-MSH, γ-MSH) and Adrenocorticotropic hormone (ACTH)

Flashcard 3

Front: What are the enzymes that cleave POMC called? Back: Convertases

Flashcard 4

Front: What determines the different products formed from POMC? Back: Different convertases

Flashcard 5

Front: How many melanocortin receptors are there? Back: 5

Flashcard 6

Front: What type of receptors are melanocortin receptors? Back: 7-membrane, G-coupled protein receptors

Flashcard 7

Front: Name two melanocortin antagonists. Back: Agouti, agouti related protein (AGRP)

Flashcard 8

Front: Name two proteins that modulate melanocortin activity. Back: Mahogany, syndecan-3

Flashcard 9

Front: Name an opioid peptide that is a product of POMC but not part of the melanocortin system. Where is it produced and what is its function mentioned in the text? Back: β-endorphin (pituitary, blocks pain)

Flashcard 10

Front: Is the posttranslational processing of POMC the same in all tissues? Back: No, posttranslational processing of POMC is tissue-specific

Flashcard 11

Front: What does α-MSH produced in the brain inhibit? What can a mutation in this process result in? Back: Food intake; early onset diabetes

Flashcard 12

Front: What cells in the skin does α-MSH act on? What do these cells contain and influence? Back: Melanocytes; melanin/pigment which influence human skin colour & rodent coat colour

Flashcard 13

Front: What can a mutation in the production or action of α-MSH in the skin result in? Back: Altered pigmentation

Flashcard 14

Front: Name some tissues where melanocortin receptors (MCR) are produced. Back: Adrenals, skin, brain, penis, etc.

Flashcard 15

Front: A mutation in MCR in which tissue is associated with sexual function/dysfunction? Back: Penis

Flashcard 16

Front: What effect does α-MSH have on skin pigment? Back: Increases dark pigment in skin

Flashcard 17

Front: What receptor does α-MSH bind to in the skin to increase dark pigment? Back: MC1R

Flashcard 18

Front: Binding of α-MSH to MC1R activates what? Name some examples provided in the text. Back: Signal pathways (G-protein-coupled receptors, cAMP, PKA, CREB)

Flashcard 19

Front: What transcription factor's synthesis is influenced by the signaling pathways activated by α-MSH binding to MC1R? Back: MITF (microphthalmia-associated transcription factor)

Flashcard 20

Front: What genes, involved in pigmentation, are transcribed due to the signaling pathways activated by α-MSH binding to MC1R? Back: Tyr & DCT

Flashcard 21

Front: What was discovered in Agouti mice in 1905? Back: A spontaneous mutation

Flashcard 22

Front: What is overproduced in Agouti mice due to the mutated gene? Back: Agouti protein

Flashcard 23

Front: What receptor does Agouti protein act as an antagonist to in the skin? What is the result? Back: MCR1; yellow pigmentation

Flashcard 24

Front: What receptor does Agouti protein act as an antagonist to in the brain? What are the results? Back: MCR4; overeating & obesity

Flashcard 25

Front: Agouti mice are a model for what conditions? Back: Adult-onset obesity, hyperglycemia, & insulin resistance

Flashcard 26

Front: What genetic condition causes 6% of jaguars to be black? What is the genetic basis of this condition? Back: Melanism; a dominant gene mutation in MC1R

Flashcard 27

Front: What is the genetic basis of red hair according to the text? Back: Results from 2 copies of a recessive mutation in the MC1R protein

Flashcard 28

Front: Mutations in which melanocortin receptor are linked to erectile dysfunction? Back: MC4R

Flashcard 29

Front: What type of drugs are used to treat erectile dysfunction and give an example mentioned in the text? Back: α-MSH analogs; Melanotan II

Flashcard 30

Front: What receptors does Melanotan II bind to in the brain to increase sexual function? Back: MC3R & MC4R

Flashcard 31

Front: Name two hypothalamic hormones that stimulate prolactin release. Back: PRH, TRH

Flashcard 32

Front: Name a hypothalamic hormone that inhibits prolactin release. Back: Dopamine (PIH), GHIH

Flashcard 33

Front: What anterior pituitary hormone controls milk production? Back: Prolactin

Flashcard 34

Front: What anterior pituitary hormone's secretion decreases after birth? Back: Estrogen

Flashcard 35

Front: What anterior pituitary hormone's secretion increases after birth and is crucial for milk production? Back: Prolactin

Flashcard 36

Front: What posterior pituitary hormone controls milk release? Back: Oxytocin

Flashcard 37

Front: What triggers the release of prolactin? Back: Suckling stimulus

Flashcard 38

Front: What stimulates the release of oxytocin? Back: Suckling stimulus, visual/auditory cues (i.e. brain stimuli), or even the thought of the child

Flashcard 39

Front: Name a protein found in breast milk. Back: Casein, lactalbumin

Flashcard 40

Front: Name a carbohydrate found in breast milk. Back: Lactose

Flashcard 41

Front: What immunoglobulin is found in breast milk? Back: Immunoglobin A (IgA)

Flashcard 42

Front: What hormone has been suggested to play a role in behavior & trust? Back: Oxytocin

Flashcard 43

Front: What is the name of the sex-determining region located on the Y chromosome? Back: SRY gene

Flashcard 44

Front: What is the role of the SRY gene? Back: Induces embryonic gonads to become testes

Flashcard 45

Front: What develops in the absence of the SRY gene? Back: Ovaries

Flashcard 46

Front: What protein, produced due to the presence of the SRY gene, leads to the development of testes? Back: SRY protein

Flashcard 47

Front: What hormone is produced by the developing testes in males that helps maintain the Wolffian duct? Back: Testosterone

Flashcard 48

Front: What cells in the developing testes produce Mullerian Inhibition Factor (MIF)? Back: Sertoli cells

Flashcard 49

Front: What is the role of MIF in male fetal development? Back: Causes the Mullerian duct to degenerate

Flashcard 50

Front: What duct develops into the seminal vesicle, vas deferens, & epididymis in male fetal development? Back: Wolffian duct

Flashcard 51

Front: What ducts are maintained in female fetal development due to the absence of SRY protein and testosterone? Back: Mullerian ducts

Flashcard 52

Front: What develops from the Mullerian ducts in female fetal development? Back: Fallopian tube, uterus, & vagina

Flashcard 53

Front: During the first 6 weeks of development, are the external genitalia of males and females the same or different? Back: Essentially identical

Flashcard 54

Front: What hormone masculinizes the external genitalia in males? Back: Secretions of testes (including testosterone)

Flashcard 55

Front: In the absence of testosterone, what does the genital tubercle form in females? What do the labioscrotal swellings become? Back: Clitoris; labia majora

Flashcard 56

Front: What is the diploid number of chromosomes in most human cells? How many are autosomes and how many are sex chromosomes? Back: 46; 22 homologous pairs of autosomes and 1 pair of sex chromosomes

Flashcard 57

Front: What is the haploid number of chromosomes in human oocytes and sperm? Back: 23

Flashcard 58

Front: What are the sex chromosomes for genetic females? What are they for genetic males? Back: XX; XY

Flashcard 59

Front: What can result from abnormal SRY recombination? Back: XX male (with SRY on X) or XY female (no SRY)

Flashcard 60

Front: What family of receptors is required for testes determination? Name three members. Back: Insulin receptor family; Insulin receptor (INSR), Insulin-like growth factor 1 receptor (IGF1R), Insulin receptor-related receptor (INSSR)

Flashcard 61

Front: What is the definition of true hermaphrodites (intersex) provided in the text? Back: Sexual development disorder where individuals have both ovary & testis tissue

Flashcard 62

Front: What is the approximate birth prevalence of children born with noticeably atypical genitalia requiring a specialist in sex differentiation? Back: ~1 in 1500-2000 births (0.07-0.05%)

Flashcard 63

Front: What is the definition of pseudohermaphrodites (intersex) provided in the text? Back: Congenital endocrine disorder where an individual has external genitalia of one sex & internal sex organs of the other sex

Flashcard 64

Front: What enzyme converts testosterone to DHT? Back: 5a-reductase

Flashcard 65

Front: What happens to males with a defective 5a-reductase gene during fetal development and puberty? Back: Male external genitalia & prostate gland fail to develop fully during fetal development, born with external genitalia that appears female; upon onset of puberty, testes secrete testosterone causing masculinization of external genitalia, lower voice, etc.

Flashcard 66

Front: In 2013, what option did Germany introduce for babies with characteristics of both sexes on birth certificates? Back: Allowed to leave gender blank, creating a new category of “intermediate sex”

Flashcard 67

Front: What gender option was introduced on passport applications in Australia and New Zealand? Back: “X” for gender (indeterminate, unspecified, intersex)

Flashcard 68

Front: What term is used in Bangladesh, Nepal, Pakistan, and India for an additional gender category on official documents? Back: "Other" or 3rd gender

Flashcard 69

Front: In Ontario, Canada, what changes were made regarding gender display on health cards and driver's licenses? Back: Ontario health cards no longer display sex designation; Ontario drivers given the option to display “X” as gender identifier on driver’s licenses

Flashcard 70

Front: What event marks the activation of the HPG axis leading to gonadal maturation? Back: Puberty

Flashcard 71

Front: What happens to FSH and LH levels at birth and before puberty? Back: ↑ FSH & LH at birth, remaining high for the first 6 months of postnatal life before declining to very low levels until puberty

Flashcard 72

Front: What hormone triggers puberty according to the text? Is its secretion steady or pulsatile? Back: LH; pulsatile

Flashcard 73

Front: What stimulates the pulsatile release of LH at puberty? Back: ↑ GnRH secretion

Flashcard 74

Front: Increased LH leads to increased secretion of what hormones from the testes and ovaries? Back: Testosterone from testes & estradiol from ovaries

Flashcard 75

Front: The increase in sex hormone secretion during puberty results in the development of what? Back: Secondary sex characteristics

Flashcard 76

Front: How is GnRH released? Back: In pulses rather than steadily

Flashcard 77

Front: What happens to individuals with GnRH deficiency if left untreated? Back: Fail to sexually mature

Flashcard 78

Front: For GnRH treatment to be effective, how must it be administered? Back: In pulses similar to those that occur naturally

Flashcard 79

Front: What factors can cause variations in the timing of puberty? Back: Genetic variations, environmental factors (e.g. ↑ altitude results in later onset), nutrition, chronic illness, theoretical concern over synthetic hormones & other environmental chemicals

Flashcard 80

Front: What is the term for very early onset of puberty? Back: Precocious puberty