Albert J. Fivizzani, Jr
Professor (Emeritus)
B.S., 1968, M.S., 1971, De Paul University;
Ph.D., 1977, Louisiana State University.
Vertebrate Physiology, Biological Rhythms, Hormonal Control of Behavior.
Tel. (701) 777-4671 or 777-2621.
As a comparative endocrinologist I am interested
in similarities and differences among vertebrates
in the regulation of physiological processes.
Comparative endocrinology has as its foundation
an interest in the evolution of hormone molecules
and their functions. In vertebrates, some hormones
such as the gonadal steroid hormones have maintained
their basic regulatory roles in reproduction
during evolution. In contrast, other hormones
such as prolactin are utilized for a variety
of purposes such as osmoregulation in fish, incubation
behavior in birds and milk production in mammals.
I am presently involved with research in two general areas. First is the role of gonadal
steroid hormones deposited in the yolk of reptiles on sex determination in species
with temperature-dependent sex determination (TSD). In these species, the
temperature at which the eggs are incubated determines the sex of the offspring. The
molecular mechanism responsible for determining sex in these species has not
been fully elucidated. We have studied the dynamics of yolk steroid hormone
content during embryonic development in snapping turtles and alligators. Estradiol
levels are altered differently under different incubation temperatures in both
these reptiles. We believe that this difference in hormone utilization
is involved in the mechanism of sex determination. My second area
of research involves the role of hormones in the reproductive and parental behavior
of several species of shorebirds in which the females are more aggressive than
males, and males primarily or exclusively incubate eggs. Many behaviors are caused
by hormone action and, in turn, behavioral interactions and environmental changes
alter hormone production and release. By means of the techniques of microradioimmunoassay,
hormone levels can be measured from small volumes of blood. This technique allows
for hormonal studies on small organisms as well as repeated collections of blood
samples from individual animals. I also study the mechanism by which gonadal
steroid
hormones interact with brain tissue and activate specific behaviors.
I am also interested in the interaction between biological rhythms and hormones
in vertebrates. I have studied the effects of different environmental conditions
on biological rhythms and the interaction of multiple hormone rhythms on the
annual cycle of reproduction and seasonal changes in salinity preference in fish.
Environmentally induced changes in the daily rhythms of the hormones prolactin
and adrenal corticosteroids can initiate the development of specific seasonal
conditions of reproduction, metabolism and behavior in vertebrates from fish
to mammals.
Representative Publications:
Plasma steroid hormones in relation to behavioral sex role reversal in the
spotted sandpiper, Actitis macularia . 1986. Biol.
Reprod . 35:1195-1201. (with L.W. Oring).
Hormonal changes associated with natural and manipulated incubation in the
sex role reversed Wilson's phalaropes. 1988. Gen. Comp. Endocrinol. 72:247-256.
(with L. W. Oring, M.A. Colwell and M.E. El Halawani).
Hormonal basis of male parental care and female intrasexual competition in
sex-role reversed birds. 1990. pp. 273-286. In : Endocrinology of
Birds: Molecular to Behavioral. (M. Wada, S. Ishii and C.G. Scanes, Eds.) Japan
Sci. Soc. Press, Tokyo/Springer-Verlag, Berlin. (with L.W. Oring, M.E.
El Halawani and B.A Schlinger).
Seasonal changes in gonadal steroids of a monogamous versus a polyandrous subarctic
shorebird. 1990. Gen. Comp. Endocrinol. 80:407-418. (with C. L.
Gratto-Trevor, L.W. Oring and F. Cooke).
Yolk steroids decline during sexual differentiation in the
alligator. 1997. Gen. Comp. Endocrinol. 107:191-200. (with J. J.
Conley, P. Elf, C.J. Corbin, S. Dubowsky, and J.W. Lang).
An analysis of
sex and breeding stage differences in prolactin binding activity in brain and
hypothalamic GnRH concentration in Wilson=s phalarope, a sex role-reversed
species. 1998. Gen. Comp. Endocrinol. 109:119-132. (with
J. D. Buntin, M.E. El Halawani, M.A. Ottinger, and Y. Fan).
The role of yolk steroid hormones in reptile sex determination. 2001.
Pp. 211-217. IN: Perspective in Comparative Endocrinology: Unity and
Diversity. H.J Th. Goos, R.K. Rastogi, H. Vaudry and R. Pierantoni (eds.). Monduzzi
Editore, Bologna, Italy. (with P.K. Elf, J. Allsteadt, and J. Lang).
Yolk hormone levels in the eggs of snapping turtles and painted
turtles. 2002. Gen. Comp. Endocrinol. 127:26-33. (with P.K. Elf, and
J.W. Lang)
Dynamics of yolk steroid hormones during development in a
reptile with temperature-dependent sex determination. 2002. Gen. Comp.
Endocrinol. 127:34-39. (with P. K. Elf, and J.W. Lang). |
