1. THE ROLE OF METAL IONS IN MALE
REPRODUCTION
By
Falana Benedict Abiola
B.Sc.(Hons), Ilorin 2002; M.Sc. Ile-Ife 2009
Matric Number: 109091016
Department of Anatomy, College of
Medicine of the University of Lagos.
Nigeria.
Practice Seminar II

2. OUTLINE
Introduction
Transport/storage problems
Mechanism of membrane transport
Classification
Bioavailability of ions
Literature review
Conclusion
References

3. INTRODUCTION
A metal atom that has either lost
or gained an electron
A metal ion is thus a metal atom
with a charge.

4. INTRODUCTION
Exert a wide variety of adverse
effects on reproduction and
development( Apostoli and Catalini 2011).

5. INTRODUCTION
 Metalloenzymes
hydrolytic enzymes
catalyze addition or removal of water in a
substrate
e.g. carbonic anhydrase catalyzes CO2 + H2O →
H2CO3
redox enzymes
catalyze oxidation/reduction of substrate
e.g. oxidation of hydrocarbons to alcohol by cyt-
P450 (Fe-porphyin)
e.g. nitrogenase: reduces N2 to NH3 (6 electron

6. INTRODUCTION
Specific Metal Ions.
Calcium - Zinc
Chromium -Phosphorus
Potassium -Manganese
Selenium - Other heavy metals like Cd, Pb

7. Part of the male reproductive tract .
Pastor-Soler N et al. Physiology 2005;20:417-428
©2005 by American Physiological Society

8. ION TRANSPORT
Capture of Trace Ions from the Environment
Control of Concentration is essential for life
Bulk ions present in high concentration
Trace ions must be actively accumulated
Selectivity of Ion Uptake is Essential
Toxic ions must be excluded
Beneficial ions must be accumulated

9. ION TRANSPORT
Charged Ions must pass through a
Hydrophobic Membrane
Neutral gases (O2, CO2) and low charge
density ions (anions) can move directly
through the membrane
High charge density cations require help
Once

10. MECHANISMS FOR MEMBRANE
TRANSPORT
Ionophores: special carrier molecules that
wrap around metal ions so they can pass
through the membrane by diffusion.
Ion Channels: large, membrane-spanning
molecule that form a hydrophilic path for
diffusion
Ion Pumps: molecules using energy to
transport ions in one direction through a
membrane

11. MECHANISMS FOR MEMBRANE
TRANSPORT
Passive Transport: moves ions down the
concentration gradient, requiring no energy
source
Active Transport: moves ions against the
concentration gradient, requiring energy from
ATP hydrolysis

12. CLASSIFICATION OF MINERALS
Macro or Major
minerals
Sodium,
potassium,
magnesium,
calcium,
phosphorus,
sulfur,
chloride.
 Micro or Trace
minerals (body
needs relatively
less)
Chromium,
manganese, iron,
cobalt,
molybdenum,
copper, zinc,
fluoride, iodine,
selenium,
silicon, tin,
arsenic, nickel.

13. CALCIUM
 Developing and maintaining
healthy bones and teeth,
 Blood clotting, muscle
contraction and nerve
transmission, oxygen transport,
cellular secretion of fluids and
enzyme activity, optimal intake
helps reduce the risk of
osteoporosis.

14. CHROMIUM
Aids in glucose metabolism
Potentiates insulin and serves as a
component of glucose tolerance
factor.

15. POTASSIUM
Regulates heartbeat
maintains fluid balance
 helps muscle contract.

16. SELENIUM
 Component of glutathione peroxidase
catalyzes removal of hydrogen peroxide
 Component of iodothyronine-5’- deiodinase
Converts T4 to T3
 Improves killing ability of neutrophils
GSH = reduced glutathione
GSSG = oxidized glutathione
GSH + H2O2 GSSG + H2O

17. PHOSPHORUS
Works with calcium to develop and
maintain strong bones and teeth
 Enhances use of other nutrients
 Plays a key role in cell membrane
integrity and intercellular
communication critical for proper
energy processing in the body.

18. MANGANESE
Key component of enzyme
system including oxygen handling
enzymes, supports brain function
and reproduction.
Required for blood sugar
formation and part of bone
structure.

19. MINERALS
Essential minerals Essential trace and
minerals
Non essential
contaminant
minerals
Calcium Chromium Aluminum
Chloride Copper Arsenic (in abundance)
Magnesium Cobalt Barium
Phosphorus Fluorine Beryllium
Potassium Iodine Cadmium
Sodium Iron Lead
Sulphur Manganese Lithium
Molybdenum Mercury
Selenium Rubidium
Vanadium Strontium
Zinc REFERENCE: NFM 38,
NFM Nutrition Science
News; December 2005

20. MINERALS
Mineral Contaminate body part
affected
Protective nutrient
Aluminum Stomach bone brain Possibly magnesium
Arsenic Cells (cellular metabolism) Selenium, iodine, calcium
zinc, vitamin C, sulphur
amino acids)
Cadmium Renal cortex of the kidney,
Heart, blood vessels to the
brain appetite and smell
centre, every known process
in the development of
Cancer
Zinc, Calcium, Vitamin C
Sulphur ammo acids
Lead Bone, Liver, Kidney,
Testes,Pancreas Heart,
Brain, Nervous system
Zinc, Iron Calcium, Vitam
C, Vitamin E, Sulphur,
Amino acids
Mercury Nervous system, appetite
and pain centre of the brain,
Immune system Cell
membranes
REFERENCE: NFM 38,
NFM Nutrition Science
News; December 2005

21. NON ESSENTIAL MINERALS
Humans are exposed to
environmentally and
occupationally to metal aerosols
including lead and cadmium (Benoff
et al., 2000;Akinloye et al 2006 ).
These toxicant accumulate in
male reproductive organs (Benoff et
al., 2000).

22. CA+ AND K+ CHANELLS
Multiple Ca2+ and K+ Channels
have been identified in human testes
and spermatozoa
 These channels are involved in early
events of acrosome reactions, these
channels offer entry paths for metallic
toxicants into mature spermatozoa.
(Benoff et al., 2000)

23. REPRODUCTIVETOXICANTS
2,5 hexanedione ( Sertoli cell
toxicant),
Ethylene glycol monomethyl ether
EGME; (Spermatocytes toxicant),
Cyclophosphamide
(Spermatogoonia toxicant), and
Sulphalazin. Fukushima et al., (2005)

24. BIOAVAILABILITY
Bioavailability
Influenced by genetics, aging,
nutritional status & other food
compounds
Absorption
Small intestine & large intestine
Regulation
Kidneys & small intestine

25. BIOAVAILABILITY

28. WHY ARE CERTAIN METAL IONS
INVOLVED?
A. Rule of Abundance
when a process can be accomplished using
any of several metal ions, then the molecule
will “pick” the most abundant ion
e.g. Ca+2
and Sr+2
carbonate/phosphate
compounds equally insoluble. Why aren’t
bones made from Sr? (Ca is much more
abundant)
e.g. Zn enzymes can use Co+2
effectively, but
“chose” Zn because it is much more abundant

29. WHY ARE CERTAIN METAL IONS
INVOLVED?
B. Rule of Efficiency
an organism will utilize the most efficient ion if
two are in equal abundance
e.g. two electron carriers:
flavodoxins (-0.185V potential) with no metal
ion
ferridoxins (-0.420V) Fe-S metalloenzyme
both are similar in function, but the ferridoxins are
much more efficient and powerful than the
flavodoxins and are therefore employed more

30. WHY ARE CERTAIN METAL IONS
INVOLVED?
C. Rule of Basic Fitness (Most
Important!)
no matter how abundant an ion
is, if it can’t do the job it isn’t
going to be used.
the ion has to function in an
aqueous solution at neutral pH
and ~25o
C, so most “jobs” can
only be performed by a limited
number of ions.

31. LITERATURE REVIEW
Metal ions act as matchmakers
for proteins. Yi Lu ( 2009).
Match makers for single domain
proteins. Salgado et al (2010).

32. METAL IONS AND
REPRODUCTION
Mercury intoxication has been
associated with male reproductive
toxicity in the experimental
animals.
( Rao and Sharma 2001).

33. METAL IONS AND REPRODUCTION
Selenium and zinc administration
was reported to attenuate lead
reproductive toxicity in male SD-
rats ( Falana and Oyeyipo 2012)

34. METAL IONS AND
REPRODUCTION
Mercury may induce oxidative
damages in rat tissues as
evidenced by increase in MDA
levels and depleted GSH
content. (Sener et al., 2003)

35. METAL IONS AND
REPRODUCTION
Mercury produces a
significant reduction in
epididymal sperm viability
and motility in murines
 (Rao and Sharma 2001)

36. METAL IONS AND REPRODUCTION
Zinc is an essential trace element
for spermatogenesis (Yamaguchi et
al., 2009)
Co administration of zinc with
folic acid has been shown to boost
penile enlargement. (Yamaguchi et
al., 2009)

37. METAL IONS AND
REPRODUCTION
 Zinc plays an important role in DNA replication,
transcription and protein synthesis influencing cell
division and differentiation (Anderson and Desmic 1999)
 Zinc is a critical element in male reproductive system
for proper hormonal metabolism, sperm formation and
motility, zinc deficiency has been associated with
impotence and reduced sexual performance (Modupe
Ogunlesi 2009)

38. METAL IONS AND REPRODUCTION
Occupational and environmental
exposures to toxic pollutants
contributes significantly to
declining sperm concentrations
and male infertility (Carlsen et al.,
1992, Agar et al., 1995,, Adamopoulous et al.,
1996, Bcker and berhane 1997)

39. METAL IONS AND REPRODUCTION
These study was criticized
because it fails to consider that
sperm counts clearly differ by
geographic location (Fisch and
Golubuff 1996; Paulsen et al 1996; Carlsen et al., 1992)

40. METAL IONS AND REPRODUCTION
Nonethe less geographic
variations in semen quality (Fisch and
Goluboff 1996; becker and Behane 1997) may still
be inluencd by environmental
factors ( Fisch and Goluboff 1996) which
exhibit considerable variation
between climatic seasons (Sram et al
1996)

41. METAL IONS AND REPRODUCTION
More importantly, environmental
factors differ between areas ( Friberg
and Vahter 1983., Svenson et al 1987; Buchancova et al.,
1994; Sram et al.,1996) with higher amount
of pollutants closer to sources of
industrialisation (Benin et al., 1999)

42. METAL IONS AND REPRODUCTION
Pb2+ and Cd2+ prefentially
accumulate in male reproductive
organs ( Danielson et al., 1984; Oldereid et al.,
1993; jackson et al 1995)
An increase in Pb2+ and Cd2+
often occur simultaneously ( Stachel
et al., 1989)

43. METAL IONS AND REPRODUCTION
Several death pathways will be activated
following lead toxicity .(Kumari et al.,2013)
Mitochondrial pathway which involves
the inhibition of the heme a3-cuBeta
binuclear centre of Ccox: an enzyme
concerned with the conversion of
molecular oxygen into water at complex
V of the ETC.

44. METAL IONS AND REPRODUCTION
Previous studies have shown that
heavy metals like Mercury,
cadmium and lead are capable of
inducing wide range toxicity in
the germinal epithelium (Xiao et al.,
2010)

45. METAL IONS IN REPRODUCTION
Morphometric studies reveals low
cell count, distorted lumen and
cell death in general;
Other physiological changes
include male infertility and
tumorigenesis (Xiao et al., 2012)

46. SUMMARY AND CONCLUSION
Terminating the cause(s)
Nanoparticles awareness
Government policies
Occupational and environmental
problems revisited.

47. THANKS
Thanks for listening.

48. REFERENCES
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49. REFERENCES
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