AJP - Regulatory, Integrative and Comparative Physiology, Vol 259, Issue 2 341-R349, Copyright © 1990 by American Physiological Society
Armenian hamster female protein: a pentraxin under complex regulation
J. E. Coe and M. J. Ross
Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840.
The serum of Armenian hamster (Cricetulus migratorius) contains a protein
homologous to female protein (FP) that has been characterized in the Syrian
(golden) hamster. Of unknown function, FP belongs to a family of proteins
(called pentraxins) that have a common ancestral gene and are widely
expressed in nature. Whereas serum concentration of FP in Syrian hamsters
(SFP) is many fold greater (200- to 300-fold) in females vs. males,
Armenian hamster FP (AFP) is only moderately elevated (approximately
3-fold) in female vs. males and only for the fall-winter months of the
year. In the Armenian hamster testosterone administration to females or
castration of males has no effect on AFP serum levels, whereas in Syrian
hamster these treatments change SFP serum concentration to that
characteristic of the opposite sex. Some sex steroid control of hepatic AFP
synthesis is evident, however, as serum levels decrease after exogenous
estrogen treatment. In contrast to Syrian hamster FP, normal levels of AFP
are dependent on an intact hypophysial-pituitary axis and also are
influenced by the season of the year. As an acute-phase protein, AFP
responds in a typical fashion, with increasing serum levels detected in
both sexes in contrast to the divergent sex-limited response in Syrian
hamsters. Although AFP and SFP are similar structurally, morphologically,
and antigenetically and share common binding specificities, the regulation
of FP synthesis in Armenian hamster is very different from that previously
found in Syrian hamster.
