BIO 351 Endocrinology, Medgar Evers College
April 3, 2006
Male Reproductive Endocrinology
Kenneth L. Campbell
Prof. of Biology; Assoc. Dean of Science & Mathematics
University of Massachusetts at Boston
This presentation is made possible
by a grant entitled
“Shortcourses in Endocrinology at
Minority Undergraduate Institutions”
from the
National Institute of General Medical
Sciences (NIGMS)
to
The Minority Affairs Committee of the
Endocrine Society
SUMMER RESEARCH OPPORTUNITIES FOR
MINORITY STUDENTS
Are You Interested In:
• Going away for the summer in 2007 to do research for 8 weeks in a
cutting-edge endocrine lab in an area of your choice with a caring
mentor?
• Receiving a two-year free membership in The Endocrine Society
with many benefits, e.g., information about travel grants,
scholarships, online journals, etc.?
http://www.endo-society.org/minorityactivities/summer_research.cfm
SUMMER RESEARCH OPPORTUNITIES FOR
MINORITY STUDENTS
How do I qualify and What should I do?
You can apply if you are:
• A full-time minority student beyond your sophomore year or if
you are currently enrolled at a minority institution, and
• A U.S. citizen or permanent resident.
For more details on eligibility and requirements, visit The
Endocrine Society website at
http://www.endo-society.org/minorityactivities/summer_research.cfm
What are endocrine systems for?
Endocrine Functions
• Maintain Internal Homeostasis
•
•
•
•
Support Cell Growth
Coordinate Development
Coordinate Reproduction
Facilitate Responses to External Stimuli
Feedbacks Generate Control Loops
Negative
+
--
These
maintain
hormonal
balance
& are often linked
What
are
feedback
systems?
to homeostatic processes.
If the multiplicative effect of the several links in a
control loop is negative, the entire control loop is
negative.
Positive
+
+
These cause physiologic changes in the system
involved.
If the multiplicative effect of the several links in a
control loop is positive, the entire control loop is
positive.
How dynamic are these systems?
Hormone, receptor, transducer & effector levels
vary with time. Some change over short terms,
others over long terms.
Levels also vary with developmental stage,
gender, & health status.
www.antiaging.com/images/ testosterone_decline.gif
After a248.e.akamai.net/.../pubs/mmanual_home/ illus/i232_1.gif
Outline of Male Reproduction
1. Adult anatomy
2. Embryogenesis
3. Sex determination
4. Hormonal controls
5. Puberty
6. Testicular anatomy
7. Meiosis
8. Spermatogenesis
9. Contraception
10. Aging
Adult Male Anatomy
Male Embryogenesis
Male Germ Cell Migration
www.med.unc.edu/embryo_images/unitgenital/genital_gifs/genital008-1.gif
www.med.unc.edu/embryo_images/unitgenital/genital_gifs/genital008-2all.gif
Sex Determination: Genetic
Sex Determination: Gonadal
www.med.unc.edu/embryo_images/un
it-genital/genital_gifs/genital010-1.gif
Sex Determination:
Internal Reproductive Tract
Sex Determination:
External Reproductive Tract
Pituitary- Hypothalamic Associations
www.cushings-help.com/ anterior-pituitary.gif
How are the gonads controlled?
LH
© Kenneth L. Campbell, 1997. All rights reserved.
How are the gonads controlled?
FSH
© Kenneth L. Campbell, 1997. All rights reserved.
Inhibin
Female
Males lack inhibin A.
Inhibin B is inversely
correlated with FSH
& spermatogenesis
in normal adults.
europe.obgyn.net/nederland/mp/o
vergang/images/overgang14x.gif
Steroid
Synthesis
arbl.cvmbs.colostate.
edu/hbooks/pathphys/
endocrine/basics/ster
oidogenesis.gif
Maturation: Hormonal
Leydig Cell Populations
Lejeune, H, R
Habert, JM Saez,
Origin, proliferation
and differentiation
of Leydig cells, J
Mol Endocrinol
20:1-25, 1998.
Maturation: Tanner Stages
a248.e.akamai.net/7/248/430/20020531071032/www.
www.cuhk.edu.hk/proj/growth
www.cuhk.edu.hk/proj/growthstd/
merck.com/pubs/mmanual_home/illus/i258
std/images/bpuberty.gif
images/gpuberty.gif
Testosterone in saliva
in children & serum
SHBG in adolescents
& adults. The pubertal
decrease in SHBG is
less pronounced in
women.
www.biomedcentral.com/content/
figures/1471-2431-2-5-3-l.jpg
Testicular Anatomy
trc.ucdavis.edu/mjguinan/apc100
/modules/Reproductive/mammal/
images/testis10.jpg
Meiosis: Males & Females
Male
Female
Spermatogenesis
Sperm Maturation
Spermatozoa reach
final shape in the
testis, but they gain
functional maturity
while passing through
the epididymus &
female reproductive
tract: activation of full
motility, capacitation,
in the vagina & cervix;
final fertilizing ability
after the acrosome
reaction, usually near
the egg.
Fertilization
Male Contraception
Barriers
condoms
Vasectomy
Hormones
peripheral androgens
+/- LHRH antagonists
or agonists
MaleMale
Serum
Hormone
Aging
&
Age Profiles
Reproductive
Senescence
www.dpcweb.com/documents/news&views/spring_02/the_aging_male.html
The ratio T/SHBG
is the FAI, a
Measure of free T.
Adrenal androgens
like DHEAS also
decline with age.
www.dpcweb.com/documents/news&views/spring_02/the_aging_male.html
Low Fertility in Gainj vs Other Groups
How is prolactin controlled?
FSH in Gainj Men
LH in Gainj Men
Many Gainj Men are Infertile
Acknowledgements
Support from: NSF, Umass/Boston, Sandia National Labs,
Hybritech, Quidel, Monoclonal Antibodies Inc.
Gainj Project
Turkana Project
The Gainj People
Rees Midgley
Al Hermalin
Lora Myers
Jim Wood
Pat Johnson
Ila Maslar
Diana Lai
Sam Refetoff
Peter Smouse
Peter Heywood
Michael Alpers
Brian Davison
Yan Ren
Lynne Shinto
Diane Drinkwater
Darryl Holman
Bettina Shell
All Turkana Subjects
Mike Little
Paul Leslie
Ben Campbell
Dhanesh Dookhran
Kathy Whiteman
Alexandra Evindar
William Lukas
Sandra Gray
Jeanine Quigley
Christine Sekadde
-Kigondu
Leah Kirumbi
(*in the lab at UMB)
Related Studies
Kathy O’Connor
Coralie Munro
Susannah Barsom
Ellie Brindle
Cheryl Stroud
Kai Orton
Jodiann Thompson
Yefim Proshchitskiy
Yelena Filipova
Matt Lopresti
Oliver Schultheiss
Cheryl Frederick
Steve Monfort
Malcolm Potts
David McClelland (dec)
Male Hormone Levels with Age
www.dpcweb.com/documents/news&views/spring_02/the_aging_male.html