Seasonal changes in reproductive condition and plasma levels of sex steroids in the blue cod,Parapercis colias (Bloch and Schneider) (Mugiloididae)

1987 ◽  
Vol 4 (1) ◽  
pp. 15-26 ◽  
Author(s):  
N. W. Pankhurst ◽  
A. M. Conroy
Keyword(s):  
Sex Steroids ◽  
Plasma Levels ◽  
Seasonal Changes ◽  
Reproductive Condition

Seasonal Changes in Plasma Levels of LH and Gonadal Steroids in Free-Living Willow Tits Parus montanus

1986 ◽  
Vol 17 (3) ◽  
pp. 230 ◽  
Author(s):  
Bengt Silverin ◽  
Per-Arne Viebke ◽  
Jan Westin
Keyword(s):  
Plasma Levels ◽  
Seasonal Changes ◽  
Gonadal Steroids ◽  
Free Living ◽  
Parus Montanus

scholarly journals Melatonin Controls Photoperiodic Changes in Tanycyte Vimentin and Neural Cell Adhesion Molecule Expression in the Djungarian Hamster (Phodopus sungorus)

Endocrinology ◽  
2011 ◽  
Vol 152 (10) ◽  
pp. 3871-3883 ◽  
Author(s):  
Matei Bolborea ◽  
Marie-Pierre Laran-Chich ◽  
Kamontip Rasri ◽  
Herbert Hildebrandt ◽  
Piyarat Govitrapong ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Sex Steroids ◽  
Seasonal Changes ◽  
Cell Adhesion Molecule ◽  
Neural Cell Adhesion Molecule ◽  
Brain Plasticity ◽  
Neural Cell ◽  
Djungarian Hamster ◽  
Neural Cell Adhesion

The Djungarian hamster displays photoperiodic variations in gonadal size synchronized to the seasons by the nightly secretion of the pineal hormone melatonin. In short photoperiod (SP), the gonads regress in size, and circulating sex steroids levels decline. Thus, the brain is subject to seasonal variations of both melatonin and sex steroids. Tanycytes are specialized glial cells located in the ependymal lining of the third ventricle. They send processes either to the meninges or to blood vessels of the medio-basal hypothalamus. Furthermore, they are known to locally modulate GnRH release in the median eminence and to display seasonal structural changes. Seasonal changes in tanycyte morphology might be mediated either through melatonin or sex steroids. Therefore, we analyzed the effects of photoperiod, melatonin, and sex steroids 1) on tanycyte vimentin expression by immunohistochemistry and 2) on the expression of the neural cell adhesion molecule (NCAM) and polysialic acid as markers of brain plasticity. Vimentin immunostaining was reduced in tanycyte cell bodies and processes in SP. Similarly, tanycytes and their processes contained lower amounts of NCAM in SP. These changes induced by SP exposure could not be restored to long photoperiod (LP) levels by testosterone supplementation. Likewise, castration in LP did not affect tanycyte vimentin or NCAM expression. By contrast, late afternoon melatonin injections mimicking a SP-like melatonin peak in LP hamsters reduced vimentin and NCAM expression. Thus, the seasonal changes in vimentin and NCAM expression in tanycytes are regulated by melatonin independently of seasonal sex steroid changes.

Plasma levels of immune factors and sex steroids in the male seahorse Hippocampus erectus during a breeding cycle

2017 ◽  
Vol 43 (3) ◽  
pp. 889-899 ◽  
Author(s):  
Tingting Lin ◽  
Xin Liu ◽  
Dongxue Xiao ◽  
Dong Zhang
Keyword(s):  
Sex Steroids ◽  
Plasma Levels ◽  
Breeding Cycle ◽  
Hippocampus Erectus ◽  
Immune Factors

The relationship between plasma levels of the endocannabinoid, anandamide, sex steroids, and gonadotrophins during the menstrual cycle

2010 ◽  
Vol 93 (6) ◽  
pp. 1989-1996 ◽  
Author(s):  
Mona R. El-Talatini ◽  
Anthony H. Taylor ◽  
Justin C. Konje
Keyword(s):  
Menstrual Cycle ◽  
Sex Steroids ◽  
Plasma Levels ◽  
The Relationship

EFFECTS OF PINEALECTOMY ON THE SECRETION OF LUTEINIZING HORMONE, TESTOSTERONE AND PROLACTIN IN RAMS EXPOSED TO VARIOUS LIGHTING RÉGIMES

1979 ◽  
Vol 80 (3) ◽  
pp. 397-405 ◽  
Author(s):  
G. K. BARRELL ◽  
K. R. LAPWOOD
Keyword(s):  
Luteinizing Hormone ◽  
Pineal Gland ◽  
Plasma Levels ◽  
Seasonal Changes ◽  
Peak Plasma ◽  
Plasma Concentrations

Two experiments were carried out to study the effects of controlled lighting régimes on plasma levels of LH, testosterone and prolactin in Romney rams. In the second experiment the rams were either pinealectomized or sham-operated so that the role of the pineal gland in mediating seasonal changes in reproduction could be examined. Levels of testosterone and prolactin were considerably influenced by the lighting schedule. Peak plasma concentrations of testosterone were associated with periods during which the daily photoperiod decreased, whereas plasma levels of prolactin showed a pattern of changes approximately in phase with the lighting cycles. Mean plasma concentrations of LH were low in all groups of rams, which made the detection of significant effects of any treatment very unlikely. Pinealectomy reduced the effects of changes in the daily photoperiod on the patterns of secretion of testosterone and prolactin. These findings establish the pineal gland as an organ which influences the endocrine responses of rams to photoperiodic stimuli and it is concluded that the pineal gland is probably important as a mediator of seasonal reproductive changes in these animals.

scholarly journals Seasonal Changes in Plasma Levels of Sex Hormones in the Greater Rhea (Rhea americana), a South American Ratite with a Complex Mating System

PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e97334 ◽  
Author(s):  
Diego J. Valdez ◽  
Marilina Vera Cortez ◽  
Natalia S. Della Costa ◽  
Alvina Lèche ◽  
Cristian Hansen ◽  
...  
Keyword(s):  
Mating System ◽  
Sex Hormones ◽  
Plasma Levels ◽  
Seasonal Changes ◽  
South American ◽  
Rhea Americana ◽  
Greater Rhea

Seasonal changes in the reproductive condition and body composition of free-ranging red drum, Sciaenops ocellatus

Aquaculture ◽  
2000 ◽  
Vol 190 (1-2) ◽  
pp. 89-102 ◽  
Author(s):  
Steven R Craig ◽  
Duncan S MacKenzie ◽  
Gary Jones ◽  
Delbert M Gatlin
Keyword(s):  
Body Composition ◽  
Seasonal Changes ◽  
Red Drum ◽  
Sciaenops Ocellatus ◽  
Reproductive Condition ◽  
Free Ranging
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