Reproductive hormones and their main functions

REPRODUCTIVE HORMONES AND THEIR MAIN FUNCTIONS

HORMONES: Non-nutrient chemical, synthesised in trace amounts, intracellular messengers and are specific in their action.

1. POLYPEPTIDE HORMONES: Peptide hormones are polymers of small numbers of amino acids (from fewer than ten to a few hundred); in other words, they are small proteins. 

(A). Hypothalamic gonadotrophin releasing hormone (GnRH) :It acts on the anterior pituitary cells which synthesize and release FSH and LH.
(B). Prolactin: It helps to promote breast development in pregnancy and lactation.
(C). Oxytocin: It causes uterine contraction during labour and also promotes milk ejection during breast feeding.

2. GLYCOPROTEIN HORMONES: More complex protein hormones have carbohydrate side chains and are called glycoprotein hormones. Hormones in this class are Follicle-stimulating hormone (FSH; follitropin), Luteinizing hormone (LH).

(A). Pituitary gonadotrophins
(i) Follicle stimulating hormone (FSH): Stimulates ovarian follicle growth in female and spermatogenesis in male.
(ii) Luteinizing hormone (LH) or interstitial cell stimulating hormone (CSH): Stimulates ovulation and luteinization of ovarian follicles in female and testosterone secretion in male.
(B). Placental chorionic gonadotrophins: It helps to maintain corpus luteum and as a result ovulation and menstruation are prevented during pregnancy.

3. STEROID HORMONES: Steroid hormone, any of a group of hormones that belong to the class of chemical compounds known as steroids.

(A). Oestrogen: It is responsible for the maintenance of oogenesis development of sex organs and secondary sexual characters in females at puberty.
(B). Progesterone: It prepares the endometrium for implantation of the fertilized ovum and promotes the growth and development of the breasts.
(C). Testosterone: It is responsible for the maintenance of spermato genesis, development of sex organs and secondary sexual characters in males at puberty.
(D) Adrenal androgens (DHEA): At puberty in both sexes it contributes to increase in muscle mass, sexual hair seborrhoea.






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