INVESTIGADORES
IBARGUENGOYTIA Nora
artículos
Título:
How males synchronize their reproductive cycles with females to cope with seasonal climate: An endocrinal and ultrastructural study of Phymaturus zapalensis lizards (Liolaemidae)
Autor/es:
JORGELINA M. BORETTO, GRACIELA A. JAHN, MIGUEL W. FORNÉS, VÍCTOR E. CUSSAC, NORA R. IBARGÜENGOYTÍA
Revista:
HERPETOLOGICAL JOURNAL
Editorial:
BRITISH HERPETOL SOC
Referencias:
Año: 2012 p. 33 - 34
ISSN:
0268-0130
Resumen:
Phymaturus
zapalensis inhabits harsh thermal environments in the steppe of Patagonia,
Argentina, characterized by climate conditions that impose constraints on
reproduction, providing an appealing model to study the role of steroid
hormones in the regulation of seasonal reproductive events. Males of P.
zapalensis exhibited a postnuptial spermatogenic cycle with spermiation in
mid-spring in synchrony with female ovulation time when mating occurs, followed
by testicular recrudes-cence, but do not show sperm reservoir during
hibernation period in winter. Females of P. zapalensis can reproduce annually or
biennially. Here, we studied the steroidogenic functions of testicular
compartments of P. zapalensis by analysing serum testosterone and
ultrastructure related to steroidogenic activity in Sertoli and Leydig cells,
as a possible mechanism for the synchronization of male and female reproductive
cycles. The testosterone cycle resembles the gonadal cycle in P. zapalensis previously
described by morphology and histology of testes. Testosterone concentration is
highest in mid-spring and lowest in early summer, with an initial recovery at
the beginning of a new spermatogenic cycle in late summer and early autumn. Ultrastructural
morphological features indicative of steroidogenic activity in Leydig and
Sertoli cells were observed during the spermatogenic cycle. Evidence of
temporal asynchrony in steroidogenic activity between compartments were found
in males captured in summer and autumn, while synchronous activity was found
during mating in spring. Temporal separa-tion of steroidogenic activity serves
to synchronize male and female cycles in P. zapalensis and assures the
adjustment of reproductive activity to physiological and environmental
constraints.