SM_192b: Puberty Flashcards
Puberty is ___
Puberty is maturation of the hypothalamic-pituitary-gonadal axis
Describe biochemical changes of puberty
Biochemical changes of puberty
- Increase in pulsatile GnRH secretion (hypothalamus): increased frequency and amplitude, initially at night
- Increase in pulsatile LH and FSH (pituitary): increased frequency and amplitude, initially at night, diurnal rhythm lost as puberty progresses
- Increase in estradiol or testosterone (gonad: gonadarche)
Describe puberty over the lifespan
Puberty over lifespan
- Pubertal hormones: high in fetus, low in infant, especially low in child, then increases to high in adult
- CNS inhibition of GnRH pulse generator: low in fetus, higher in infant, highest in child, then decreases
Regulation of pubertal onset involves ____ and ____
Regulation of pubertal onset involves reactivation and stimulation / release of inhibition
Regulation of onset of puberty involves excitatory and inhibitory effects on ____ secretion
Regulation of onset of puberty involves excitatory and inhibitory effects on GnRH secretion
____ and ____ are the gatekeepers of puberty
Kisspeptin and neurokinin B are the gatekeepers of puberty
Kisspeptin levels ___ at pubertal onset
Kisspeptin levels increase at pubertal onset
- Administration of kisspeptin advances timing of puberty in rats
KISS1R knockout mice have ____ GnRH neurons but ____ and ____
KISS1R knockout mice have normal GnRH neurons but gonadotropin deficiency and no puberty (hypogonadotropic hypogonadism)
KISS1 protein activates ___
KISS1 protein activates GPR54/KISS1R
TAC3 encodes ____
TAC3 encodes TACR3 / NKB receptor
____ acts upstream to release of kisspeptin, so mutations lead to ____ then ____
Neurokinin B acts upstream to release of kisspeptin, so mutations lead to hypogonadism than reversal in adulthood
(important for puberty, not reproduction)
____, ____, ____, and ____ are regulators / modulators of the hypothalamic-pituitary-gonadal axis
Gonadal steroids (T or E), metabolic hormones (leptin, ghrelin), sleep, and overall energy balance are regulators / modulators of the hypothalamic-pituitary-gonadal axis
Anorexia nervosa involves ____
Anorexia nervosa involves inadequate energy balance that suppresses production of GnRH, LH, and FSH
___ is important in the development / function of GnRH producing neurons
KAL1 / ANOS1 is important in the development / function of GnRH producing neurons
Excitatory regulation of onset of puberty occurs via ____, ____, ____, and ____
Excitatory regulation of onset of puberty occurs via leptin, KISS1 / GPR54, neurokinin B, and adequate energy balance
(KAL1 / ANOS1 -> development / function of GnRH-producing neurons)
Inhibitory regulation of onset of puberty occurs via ____, ____, and ____
Inhibitory regulation of onset of puberty occurs via GABA, beta endorphin, and MRKN3
(KAL1 / ANOS1 -> development / function of GnRH-producing neurons)
Describe puberty (gonadarche)
Puberty (gonadarche)
- Sexual maturation
- Reproductive capability
- More accurately described as gonadarche
- Maturation of hypothalamic / pituitary / gonadal axis
- Inbcrease in GnRH, LH, FSH, and testosterone or estrogen / estradiol
Adrenarche is ____
Adrenarche is maturation of the hypothalamic-pituitary-adrenal axis
- Andrenal androgens increase (DHE, DHEA-S, androstenedione)
- Independent of puberty
Puberty (gonadarche) and adrenarche are ___ but ___
Puberty (gonadarche) and adrenarche are temporally related but independent
Describe adrenarche, pubarche, gonadarche, and menarche
- Adrenarche: adrenal maturation
- Pubarche: presence of pubic hair
- Gonadarche: onset of gonadal maturation (true puberty)
- Menarche (onset of menses)