REPRODUCTION AND HORMONES
John D. Harder
Department of Evolution, Ecology, and
Organismal Biology
The Ohio State University
Columbus, Ohio 43210
USA
Introduction and Outline
 Modes of reproduction in vertebrates:
oviparity, ovoviviparity, and viviparity
 Three major stages of reproduction (females)
(1) seasonal activation, (2) ovulation,
fertilization, and embryonic development,
(3) hatching/birth, and care of young
 Key measures of reproductive rate:
Clutch size in amphibians, reptiles, birds, and
Ovarian and uterine analysis for ovulation rate
and litter size in mammals.
Reptile and Amphibian Ovaries
Ovarian Function & Ovulation
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Ovarian follicles grow and secrete estrogen during
the follicular phase of the estrous cycle.
Estrus (i.e., female sexual receptivity can be
predicted through vaginal smear cytology).
Ovulation marks the start of the luteal phase in
which corpora lutea (CL) develop from ruptured
follicles and secrete progesterone.
Counts of CL provide estimates of ovulation rate.
Ovarian analysis of yearling does provides a good
estimate the percentage of fawns breeding the
previous year.
Mammalian Ovary
►
Drawing of the mammalian
ovary illustrating (in
clockwise progression)
follicular development (from
primordial to Graafian
follicle), ovulation,
development of a corpus
luteum (CL), and regression
of the CL. (Copied with
permission from Short 1972).
Section Through Vaginal Wall
► Sections
through the
vaginal wall of the rat
and the proportions of 2
types of epithelial cells
and leucocytes that are
released into the lumen
of the vagina during each
stage of the estrous cycle.
(Copied with permission
form Turner and Bagnara
(1976)
Diestrus: leucocytes
Proestrus: basal
epithelial cells
Diestrus
Estrus: keratinized
epithelial cells
Metestrus: leucocytes
and keratinized
epithelial cells
Procedure for Slicing
► Procedure
for slicing a
fixed ovary with a razor
blade (A) and a view of
the sliced ovary showing
an antral follicle and a
CL (B)
Endocrinology of Reproduction
 Testosterone, Spermatogenesis & Breeding in males
 Anterior pituitary secretes gonadotropins: Follicle
stimulating hormone (FSH) and luteinizing hormone
(LH).
 Ovarian follicles secrete estrogen prior to ovulation;
Elevated estrogen stimulates estrus.
 Progesterone (P) secreted by CL following ovulation.
 Periodic elevation of P indicates ovulatory cycles and
sustained high level indicate pregnancy.
 Hormone Concentrations in blood and feces
Sampling procedures and hormone assays.
Annual Gonadal-Reproductive Cycle
Annual gonadal-reproductive cycle of the red-sided garter
snake illustrates a dissociated reproductive pattern (Adapted
with permission from Crews and Garstka 1982).
Hormone levels and Estrous Cycle
Temporal relationships of estrus and ovulation to circulating levels of progesterone,
estrogen, and LH during the estrous cycle of the ewe, which has preovulatory
hormone dynamics similar to many mammalian species with spontaneous ovulation
(copied with permission from Short 1972).
Birth and Parental Care of Young
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Nest success in oviparous vertebrates
Funnel traps, drift fences, and pitfall traps for
capturing dispersing young.
Mayfield method: estimating nest success in birds
Mammals: Litter size and lactation
Placental scars in bats, rodents, and carnivores
Proportion of females lactating as evidenced in
the appearance of nipples and/or milk in the
mammary gland.
Uterine Swellings
► Uterine
swellings of a
pregnant white-footed
mouse (Peromyscus
leucopus) (A) and
postpartum uterine
horns compressed
between the lid and
the inverted base of a
Petri dish to reveal
placental scars (B)
Biology of Stress
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Indicators and Measures of Stress
Behavioral indicators, food, and water consumption
Suppressed immune response and disease
Endocrine responses: size of adrenal medulla and cortex
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Anterior pituitary secretes adrenocorticotropic
hormone (ACTH)
Concentrations of adrenal corticosteroids (e.g.,
cortisol and corticosterone in blood and feces).
Pitfalls in study design and interpretation of data
Variation due to experimental procedures
Natural variation in corticosteroids
Control of Reproduction and
Wildlife Contraception.
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Hormonal and immunological methods in females.
Effectiveness of progesterone and prostaglandin
treatments.
OvoControl G Contraceptive Bait for geese.
Porcine zona pellucida (PZP) immunization interferes
with binding of spermatozoa to the egg.
GonaCon Immunocontraceptive for deer.
Research programs in Australia on virally-vectored
immunocontraception.
Summary
Summary
Reproductive rate can be assessed at 3 stages of the
 Reproductive rate can be assessed at three
reproductive cycle: (1) seasonal activation, (2) ovulation
of the
reproductive
: (1) seasonal
and stages
embryonic
development,
and (3)cycle
hatching/birth
and
careactivation,
of young (2) ovulation and embryonic development,
and (3) hatching/birth and care of young
Key measures: Clutch size in amphibians, reptiles, birds,
 Key measures: Clutch size in amphibians, reptiles,
and ovulation rate and litter size in mammals
birds and ovulation rate and litter size in mammals
Progesterone
profiles
indicate
ovulation
and pregnancy
 Progesterone
profiles
indicate
ovulation
and pregnancy
 Behavior and fecal adrenal corticosteroid levels may
Behavior and fecal adrenal corticosteroid levels may
provide
evidence
of stress
in captive
andanaimals
wild animals
provide
evidence
of stress
in captive
and wild
 Commercially available contraceptive agents show
Commercially
available
agents
show and
promise
promise for
controlcontraceptive
of reproduction
in geese
deer.
for control of reproduction in geese and deer