INVESTIGADORES
AWRUCH Cynthia Andrea
artículos
Título:
Effects of temperature on the reproductive physiology of female elasmobranchs: the case of the narrownose smooth-hound shark (Mustelus schmitti).
Autor/es:
ELISIO, M; AWRUCH C. A.; MASA A.; MACCHI, G. J.; SOMOZA, G. M.
Revista:
GENERAL AND COMPARATIVE ENDOCRINOLOGY
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Lugar: Amsterdam; Año: 2019
ISSN:
0016-6480
Resumen:
The knowledge of how temperature influences elasmobranchs reproductivephysiology allows a better understanding of their reproductive patterns. Thisstudy describes the relationship between temperature fluctuations and plasmaticchanges of sex steroids related to reproduction: Testosterone (T), Estradiol (E2)and Progesterone (P4), throughout the female reproductive cycle of theshark Mustelus schmitti. A total of 123 adult females were bi-monthly sampled in Buenos Aires,Argentina, coastal waters. Bottom temperatures were recorded at each sampling pointand blood samples were taken from each female for sex steroids measurement. Sex steroid plasma levelswere analyzed in relation with maximum follicular diameter (MFD), uterosomaticindex (USI, as indicator of pregnancy) and temperature using GeneralizedAdditive Models. Plasmatic E2 and T increased during folliculargrowth until MFD reached 1.34 and 1.46 cm, respectively. Peak of T occurred atthe follicular stage associated with parturition (MFD, 1.4-1.6 cm), just prior to finalmaturation and ovulation (MFD, 1.6-2.0 cm). Progesterone significantly increased atthis last ovarian phase, while T and E2 decreased. The increase of USIwith pregnancy was associated to a decrease in T and mainly E2 levels,while P4 remained unaffected. Estradiol plasma levels increased with temperatures below13 ºCand then progressively decreased under warmer conditions, while T presented anopposite pattern. This study provides a compelling hypothetical mechanism bywhich the endocrine system decodes seawater temperature increase (probably throughT increase and its connection with a P4 rise) to induce ovulation,and likely parturition and mating, in M.schmitti and probably other elasmobranchs.
