Biochemistry 🧪 Flashcards
(23 cards)
what are Hormones?
chemical messengers that the endocrine glands (ductless) produce and release into the bloodstream.
what is the structute of sex hormones?
Steroid hormones (containing steroid nucleus) derived from cholesterol
what is the function of sex hormones?
play an essential role in Sexual development & reproduction
where are sex hormones secreted from?
The main glands that produce sex hormones are the Adrenal glands & the gonads (ovaries in females and testes in males).
Male sex hormones (Androgens)
Female sex hormones
what is estradiol considered as?
- Most powerful & common estrogen in females
- Present in lower amount in males
Compare between (testosterone, progesterone & estradiol) according to:
- Number of carbons
- Steroid nucleus
- Structure
- production site
- Functions
Hypothalamo-Pituitary-Gonadal (HPG) Axis
Are GnRH,LH,FSH considered as sex hormones?
GnRH,LH,FSH are glycoprotein hormones not sex hormones
what is Pregnenolone considered as?
- Pregnenolone is the precursor of all other steroid hormones (androgens & mineralocorticoids)
- Pregnenolone is a Prohormone
Definition of Progestin Synthesis
Progesterone synthesis from pregnenolone
Enzyme resopnsible for Progestin Synthesis
3β- hydroxy steroid dehydrogenase (3β-HSD)
Site of Progestin Synthesis
1) Corpus luteum cells
2) Placenta during pregnancy
3) Adrenal glands
what are the steps of Androgen Synthesis in males?
what is the concentration of DHT? and what does it account for?
- About one-tenth as abundant as testosterone
- Accounts for most of testosterone’s biological action
what is the site of Estrogen Synthesis in females?
Granulosa & theca cells of ovaries
Steps of Estrogen Synthesis in females
How does females hormone synthesis vary with the menstrual cycle?
Hormone synthesis vary with the menstrual cycle:
- Estradiol→ main product in follicular phase
- Progesterone → main product in luteal phase
Extra-glandular synthesis of estrogen in females
- Aromatase is expressed in non-gonadal sites and facilitates peripheral aromatization of androgens → estrone
Includes:
a) Fat cells: converts androgen → estrone
b) Bone: converts testosterone → local estrogen to help epiphyses maturation
what is the mechanism of action of sex hormones?
which is quicker, genomic or non-genomic pathways of sex hormones action?
Non-genomic rapid pathways are much quicker than genomic pathways, which are slow and result in changes in the transcription levels of specific proteins in the cell
Summary of enzymes which participate in sex hormones synthesis
