IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
artículos
Título:
Ultrastructural and biochemical seasonal cahnges in epidydimal corpus and cauda of viscacha((Lagostomus maximus maximus)
Autor/es:
CLAUDIA AGUILERA-MERLO,; TERESA FOGAL; TIRSO SARTOR; SUSANA DOMINGUEZ; MIGUEL SOSA; LUIS SCARDAPANE; RAMÓN PIEZZI
Revista:
JOURNAL OF MORPHOLOGY
Editorial:
Wiley-Liss,Inc
Referencias:
Año: 2008
ISSN:
0362-2525
Resumen:
ABSTRACT The reproductive and adaptative behavior
of wild rodents is synchronized primarily by the photoperiod.
The viscacha, a South American rodent of nocturnal
habits and seasonal reproduction is photoperioddependent
and its reproductive behavior is regulated by
the retinohypothalamic-pituitary pineal axis. Adult
males exhibit an annual reproductive cycle with periods
of maximum gonadal activity (summer-early autumn)
and gonadal regression (winter). The corpus and the
cauda, the most sensitive segments of the epididymis to
changes induced by the photoperiod, were analyzed
using electron microscopy and enzymatic biochemistry.
During gonadal regression, principal and clear cells
showed signs of involution with respect to the activity
period. These were characterized by more irregular
nuclei, smaller cytoplasms, large vacuoles, altered mitochondria,
and glycogen deposits. All cellular populations
of the epididymal epithelium in regression presented
abundant lysosome-like dense bodies during the active
period. In addition, we measured the activity of four
acid glycosidases in the cauda epididymis along the
reproductive cycle. N-acetyl-b-D-glucosaminidase (NAG),
an enzyme that degrades endocytosed substances from
the epididymal lumen, increased significantly during gonadal
regression relative to the active period. These
results demonstrate that the viscacha epididymis exhibits
significant ultrastructural and biochemical changes
during the reproductive cycle. We demonstrate that during
regression, melatonin secretion in viscacha
increases. This study shows that the epididymal epithelium
is reduced. Thus, we postulate that the changes
observed in the epididymis are modulated by pineal melatonin.
Despite these changes, the epididymis might
maintain a microenvironment suitable for the survival
of stored spermatozoa. J. Morphol. 000:000000, 2008.The reproductive and adaptative behavior
of wild rodents is synchronized primarily by the photoperiod.
The viscacha, a South American rodent of nocturnal
habits and seasonal reproduction is photoperioddependent
and its reproductive behavior is regulated by
the retinohypothalamic-pituitary pineal axis. Adult
males exhibit an annual reproductive cycle with periods
of maximum gonadal activity (summer-early autumn)
and gonadal regression (winter). The corpus and the
cauda, the most sensitive segments of the epididymis to
changes induced by the photoperiod, were analyzed
using electron microscopy and enzymatic biochemistry.
During gonadal regression, principal and clear cells
showed signs of involution with respect to the activity
period. These were characterized by more irregular
nuclei, smaller cytoplasms, large vacuoles, altered mitochondria,
and glycogen deposits. All cellular populations
of the epididymal epithelium in regression presented
abundant lysosome-like dense bodies during the active
period. In addition, we measured the activity of four
acid glycosidases in the cauda epididymis along the
reproductive cycle. N-acetyl-b-D-glucosaminidase (NAG),
an enzyme that degrades endocytosed substances from
the epididymal lumen, increased significantly during gonadal
regression relative to the active period. These
results demonstrate that the viscacha epididymis exhibits
significant ultrastructural and biochemical changes
during the reproductive cycle. We demonstrate that during
regression, melatonin secretion in viscacha
increases. This study shows that the epididymal epithelium
is reduced. Thus, we postulate that the changes
observed in the epididymis are modulated by pineal melatonin.
Despite these changes, the epididymis might
maintain a microenvironment suitable for the survival
of stored spermatozoa. J. Morphol. 000:000000, 2008.b-D-glucosaminidase (NAG),
an enzyme that degrades endocytosed substances from
the epididymal lumen, increased significantly during gonadal
regression relative to the active period. These
results demonstrate that the viscacha epididymis exhibits
significant ultrastructural and biochemical changes
during the reproductive cycle. We demonstrate that during
regression, melatonin secretion in viscacha
increases. This study shows that the epididymal epithelium
is reduced. Thus, we postulate that the changes
observed in the epididymis are modulated by pineal melatonin.
Despite these changes, the epididymis might
maintain a microenvironment suitable for the survival
of stored spermatozoa. J. Morphol. 000:000000, 2008.
2008Wiley-Liss, Inc.2008Wiley-Liss, Inc.
KEY WORDS: viscacha; photoperiod; epididymal morphology;
lysosomal enzyme; seasonal reproduction