This document summarizes key concepts from a lecture on reproductive physiology: 1) It describes the cumulus oophorus and corona radiata, cells surrounding the ovum that are released during ovulation and may help with fertilization. 2) It provides a table summarizing reproductive hormones including their biological class, source, target tissues, and primary actions in males and females. 3) It discusses endocrine mechanisms involved in processes like the estrous cycle, pregnancy, and testicular functions. Growth factors that regulate reproduction are also outlined.

1. Lecture # 6 Prof. Dr. Nasim
Ahmad
THER 608 Lecture # 6
Physiology of Reproduction
Prof. Dr. Nasim Ahmad
Hormones and Reproduction II

2. Cumulus oophorus
At one part of the mature follicle, the cells of the
membrana granulosa are collected into a mass which
projects into the cavity of the follicle. This cluster of
cells is termed the cumulus oophorus (Latin
cumulus=heap, Greek oo=egg + phorus=carrying)
discus proligerus, and it is released with the
embedded oocyte during ovulation. In order for
fertilization to occur this layer must be penetrated by
the spermatocyte.
The corona radiata surround an ovum or
unfertilized egg cell, and consist of two or three strata
(layers) of follicular cells. They are attached to the outer
protective layer of the ovum, the zona pellucida, and their
main purpose in many animals is to supply vital proteins to
the cell. They appear at ovulation, but may disappear
eventually after fertilization.

3. Summary of Reproductive Hormones
Name Bio. Class. Source Male
Target
tissue
Female
Target
Tissue
Male
Primary
Action
Female
primary
action
GnRH Neuropeptide Hypothala
mic
surge and
tonic
Center
Ant Lobe Ant Lobe Release
of FSH,
LH
Release
of FSH,
LH
LH Glycoprotein Ant Lobe Testis
(Leydig
cells)
Ovary
(cells of
theca
interna and
luteal cells
Stimulate T
production
Ovulation,
formation
of CL and
P4
secretion
FSH Grlycoprotein Ant. Lobe Sertoli
cells
Granulos
a cells
Sertoli
cell
function
Follicular
developm
ent
3

4. Prostaglandins
20 carbon unsaturated fatty acid (arachidonic acid)
• Secreted by all body tissues especially endometrium
• Cause regression of CL. This help in the control of
estrous cycle (estrus synchronization)
• in reproductive and GI tract Contraction of smooth
muscles
• Regulate several other phenomena eg., erection, sperm
transport, ovulation, parturition etc.,
4

5. Sample Question
Pituitary gland is located in the sella turcica, a
bony depression, at the base of brain. There
are certain nomenclature of the subdivision of
the hypophysis (pituitary). Check the
INCORRECT
a) Neurohypophysis is also called Posterior
pituitary
b) Adenohypophysis is also called Anterior
pituitary
c) Neurohypophysis comprises of Median
Eminence, Inferior Stem and Neural Lobe.
d) Adenohypophysis comprises of Pars
Intermedia, Pars Tuberalis and Infundibulum.
e) a, b, c are correct while d is incorrect

6. Terminology of the Subdivisions of
the Hypophysis (Pituitary)
Pituitary gland is located in the sella turcica,a bony depression at the base of the brain
6
Neurohypophysis
(Posterior
Pituitary)
Median
Eminence
Infundibulum
Infundibular
Stem
Neural Lobe Posterior Lobe
Adenohypophysis
(Anterior
Pituitary)
Pars Intermedia
Pars Tuberalis Anterior Lobe
Pars Distalis

7. Hormone is a physiologic, organic, chemical
substances synthesized secreted by ductless
endocrine glands which passes into circulatory
system for transport and inhibits, stimulate or
regulate the functional activity of target organs or
tissues. CHECK THE CORRECT.
a)Hormones act in minute quantity, have short half
lives and bind to the nonspecific receptors.
b)Tonic centre include arcuate nucleus, preoptic
nucleus and ventromedial nucleus.
c) Pituitary gland is located in the sella turcica, a bony
depression at the base of the brain.
d)Adenohypophysis contains Pars intermedia, Pars
tuberalis, Pars distalis and median eminence
Sample Question

8. Hormones may be classified according to either
their biochemical structure, or mode of action.
CHECK THE CORRECT.
a)Steroid hormones (P4 and LH) have receptors
on the cell membrane.
b)Protein hormone (FSH and E2) crosses the cell
membrane and go into neuclus for their action.
c)Modes of intercellular communication are neural,
endocrine, paracrine and autocrine.
d)Feedback systems are not involved in the
regulation of hormone secretion.
Lecture # 6 Prof. Dr. Nasim
Ahmad
Sample Question

9. Endocrine Mechanisms
• Puberty
– Release gametes and exhibit sexual behavior
– Maturity of hypothalamo-adenohypophyseal axis
• Estrous cycle
– Tonic FSH and LH release (negative feedback)
– Preovulatory LH and FSH release (positive feedback)
• Neural Pathways
– Mating induced ovulation eg., in rabbit, camel
• Pregnancy and Parturition
– P4 from CL or placenta essential for pregnancy
– P4 PGF2a, E2, OT, fetal cortisol important for
parturition

10. Endocrine Mechanisms
• Testicular Functions
– FSH and androgens maintain gametogenic function
• Long loop: FSH-Inhibin
• Short loop: GF (interstitial cells) – Seminiferous epithelium
• Ultra short loop: Sertoli cells – Myoid cells interactions
– Each peak of LH result in peak of T about 30-45 min
later
• Sertoli Cells
• ABP, IGF and related GF proteins are internalized by
paracrine mechanisms by the germ cells
• Activins and Inhibins
– Regulate FSH but also modulate secretion of other
steroids of the gonads

11. H-P- ovarian axisH-P- testicular axis
Hypothalmo Pituitary Gonadal Axis

12. Lecture # 6 Prof. Dr. Nasim
Ahmad
Growth Factors
• Definition: They are polypeptides and proteins which are
predominantly paracrine or autocrine in promoting
mitogenic activity (target cell multiplication) in local tissue
proliferation and remodelling (eg. formation of CL), they
can alter the sensitivity or responsiveness of FSH or LH
in either stimulatory or inhibitory manner
• Three types
– IGF, EGF, activin, inhibin
– Cytokines (Macrophages, lymphocytes), affect
immune system eg., IL –1, IL-2
– CSF (colony stim factor) (WBC, RBC)
• Growth Factors and Reproduction
– Intraovarian regulators, Implantation and Gestation, Early
embryo, Uterine contractions, Leydig cell function

13. Lecture # 6 Prof. Dr. Nasim
Ahmad
Growth Factors
Name Nature/Functions
Ctyokines Produced by T4 cells that increase the synthesis of T8
cells
Epidermal Growth Factor Polypeptide with potent mitogenic activity
Fiboblast Growth Factor Polypeptide, is angiogenic
Inhibin/ activin Proteins, regulators of FSH and LH
Insulin Growth Factor Polypeptide secreted by liver and other tissues in
response to GH, regulate proliferation and differentiation
Interferons Proteins, produced by lymphocytes, is mitogenic or
antigenic (protect cells against viral infection)
Nerve Growth Factor Protein required for growth and maintenance of neurons
Platelet Activating Factor Produced by several cells (neutrophils, macrophages,
sperm cells, early embryo etc) responsible for wide
variety of reprod physio functions
Transforming Growth Factor Produced in granulosa and thecal cells, closely related to
EGF
Vascular Endo Growth
Factor
Produced by CL, its formation and regression, angiogenesis

14. Lecture # 6 Prof. Dr. Nasim
Ahmad
Some Important Facts
• Half Life of a hormone Determines how long it
will act
– Long half life (eg., eCG days)
– Short half life (eg., PGF 2
α few sec)
– Up-regulation (promote synthesis of hormone
receptors: hormones, nutrition can effect)
– Down-regulation (inhibit synthesis of hormone
receptors)
– Agonists (same bio effect as of native hormone)
– Antagonists (decrease the response of the target
cells)

15. Lecture # 6 Prof. Dr. Nasim
Ahmad
Some Important Facts
• Steroids are metabolized (inactivated) by the
liver and excreted in the urine and feces (Doping
Test ??)
• Protein hormones are degraded in the liver and
kidneys
• Hormones can be detected in physiological
fluids (blood saliva, urine, feces etc.,) using
radioimmunoassay (RIA) and enzyme linked
immunosorbent assay (ELISA)
• Thank You