Endocrinology Final Exam Flashcards
Pars distalis
Region of the adenohypophysis that has 5 cell types that secrete 6 different polypeptide structured-tropic hormones (LH, FSH, PRL, TSH, ACTH, GH)
Gonadal Recrudescence
Period of increased gonadal activity (Ex: active gametogenesis)
Oogenesis
Female egg formation/production (Oogenesis + Spermatogenesis = Gametogenesis)
Viviparous
Live birth (Ex: humans and most mammals)
Seasonal Reproduction
Occurs usually once a year and is on a yearly cycle (cyclical in that sense) (Ex: crocodiles and Alligator mississippiensis show seasonal reproduction)
Neurohormone
Bioregulators secreted from a neuron into the blood (Ex: oxytocin)
Intracrine
Type of cytocrine that affects the intracellular matrix (2nd messenger) (Ex: cAMP)
Agonist/Antagonist
Agonists mimic bioregulators, interacting/binding to the receptor and causes it to activate. Antagonists also mimic bioregulators and interact/bind to the receptor but DO NOT activate it.
Gluconeogenesis
Process of producing glucose from non-carbohydrate sources
Paracrine
A type of cytocrine that affect cells that are not of the same cytocrine cell type
Natural Selection
The differential success in the reproduction of a phenotype out of an organism’s interaction with the environment.
- Variation exists among individuals in regard to trait
- Variation is heritable
- Difference is fitness exists among individuals in a population; There is a correlation between the trait and ability to reproduce
If all of these are in place, then the phenotype in subsequent generations will be predictably different than those of previous generations
Endocrine Disruptors
Chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and/or immune effects in both humans and wildlife
Possible Effects of Endocrine Disruption
Systemic abnormalities, cancer, developmental disorders, impaired neurological function
Stress
A physiological response to any factor, environmental condition, or demand that impairs homeostasis, regulatory function, reproduction, growth, and/or Darwinian fitness
Testosterone Mechanism
Free testosterone is transported into the target tissue cell cytoplasm. It is reduced by 5-alpha-reductase to 5-alpha-di-hydro-testosterone (DHT). DHT will bind to an androgen receptor-heat shock protein complex. When DHT binds to the AR, the HSP is kicked off the AR. The DHT-AR complex then enters the nucleus through the nuclear pore complex via a 2nd messenger system. After it is in the nucleus, the DHT-AR complex will bind to a specific nucleotide sequence on the DNA. The DHT-AR complex will act as the transcription factor and mRNA transcription will be activated. The mRNA will promote the reduction of cholesterol to pregnenolone. STAR protein regulates steroid biosynthesis by controlling the transport of cholesterol from outer to inner mitochondria. Once cholesterol enters the mitochondria, CYP11A1 (a cholesterol side chain cleavage enzyme) will catalyze the conversion of cholesterol to pregnenolone. HSD3B1(hydroxy-delta-5-steroid dehydrogenase- 3 beta- and steroid delta-isomerase 1) is an oxidative reducer and converts pregnenolone to progesterone. CYP17A1 in the smooth endoplasmic reticulum is a hydroxylase that converts progesterone to androstenedione. CYP17A1 is important in steroid synthesis. The outcome of this entire mechanism is the production of androstenedione, a steroid hormone (and precursor of testosterone) used in the synthesis of testosterone. Sometimes the mRNA can travel directly to the smooth endoplasmic reticulum and bypass the mitochondria steps.
