Describe the specific action of FSH, LH, oestrogen and progesterone in the menstrual cycle.
The menstrual cycle is* controlled by rhythmic synthesis and release of ovarian hormones under feedback control from the hormones of anterior pituitary. These are discussed below:
(i) Pituitary hormones The gonadotroph cells, of anterior pituitary secrete FSH and LH in females. Their role in menstrual cycle are:
(a) Follicle Sdmulating Hormone (FSH) It is secreted during the follicular phase of the cycle and is responsible for follicular development on induction of LH receptors on granulosa cells of the ovary.
(b) Luteinising Hormone (LH) Its primary function is to stimulate the formation of corpus luteum and ’ secretion of estradiol4and progesterone from ovary.
(ii) Ovarian hormones Ovary secretes the following hormones under the effect of FSH and LH.
(a) Oestrogen It influences proliferation of the uterine endometrium to prepare for implantation of the fertilised oocyte.
Ovulation occurs and the ruptured follicles develop into corpus luteum. Secretion of LH is inhibited.
(b) Progesterone secreted from corpus luteum under
LH influence, maintains endometrium for implantation It rising levels inhibits LH .