Kisspeptin regulates ovarian steroidogenesis during delayed embryonic development in the fruit bat, Cynopterus sphinx

2017 ◽  
Vol 84 (11) ◽  
pp. 1155-1167
Author(s):  
Anuradha ◽  
Amitabh Krishna
Keyword(s):  
Embryonic Development ◽  
Ovarian Steroidogenesis ◽  
Fruit Bat ◽  
Cynopterus Sphinx

Relationship between delayed embryonic development and metabolic factors and fat deposition in fruit bat Cynopterus sphinx

2007 ◽  
Vol 19 (5) ◽  
pp. 626 ◽  
Author(s):  
Arnab Banerjee ◽  
K.J. Meenakumari ◽  
Amitabh Krishna
Keyword(s):  
Thyroid Hormone ◽  
Embryonic Development ◽  
Consumption Rate ◽  
O2 Consumption ◽  
Early Winter ◽  
Metabolic Factors ◽  
Fat Accumulation ◽  
Fruit Bat ◽  
Cynopterus Sphinx ◽  
Thyroid Hormone Levels

The present study was undertaken in the fruit bat Cynopterus sphinx, which breeds twice in quick succession at Varanasi, India. Its gestation period varies significantly in the two successive pregnancies of the year owing to delayed embryonic development during the first (winter) pregnancy. The primary aim of the present study was to determine the role of metabolic factors in delayed embryonic development in the fruit bat C. sphinx. Variation in bodyweight, fat deposition, oxygen (O2) consumption rate, basal metabolic rate (BMR), body temperature (Tb) and hepatic succinate dehydrogenase (SDH) activity, along with circulating levels of thyroid hormones (tri-iodothyronine and thyroxine), were examined as metabolic factors during the two successive pregnancies in C. sphinx. The increase in bodyweight observed in November was due to accumulation of white adipose tissue in the posterior abdominal region. A significant decline in O2 consumption rate, BMR, Tb and SDH activity was found in early winter in November–December, which coincides closely with the period of fat accumulation and with the period of delayed embryonic development in C. sphinx. A significantly higher O2 consumption rate, BMR, Tb and SDH activity was noted during the second pregnancy in, when embryonic development was relatively faster. Thyroid hormone levels were high during the period of embryonic delay compared with levels during the remaining months. The results of the present study suggest that the delayed embryonic development in C. sphinx during early winter may be due to a low O2 consumption rate, BMR, Tb and SDH activity in November–December. The energy saved by suppressing embryonic development in this species may be advantageous for fat accumulation. Increased thyroid hormone levels during the early winter period might facilitate fat accumulation in C. sphinx.

Delayed embryonic development in the Indian short-nosed fruit bat, Cynopterus sphinx

Zoology ◽  
2005 ◽  
Vol 108 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Karukayil J. Meenakumari ◽  
Amitabh Krishna
Keyword(s):  
Embryonic Development ◽  
Fruit Bat ◽  
Cynopterus Sphinx

scholarly journals Melatonin regulates delayed embryonic development in the short-nosed fruit bat, Cynopterus sphinx

Reproduction ◽  
2009 ◽  
Vol 138 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Arnab Banerjee ◽  
K J Meenakumari ◽  
S Udin ◽  
A Krishna
Keyword(s):  
Embryonic Development ◽  
Corpus Luteum ◽  
Melatonin Receptors ◽  
Melatonin Level ◽  
High Dose ◽  
Serum Progesterone ◽  
Ovarian Steroidogenesis ◽  
Cynopterus Sphinx ◽  
Progesterone Synthesis

The aim of the present study was to evaluate the seasonal variation in serum melatonin levels and their relationship to the changes in the serum progesterone level, ovarian steroidogenesis, and embryonic development during two successive pregnancies of Cynopterus sphinx. Circulating melatonin concentrations showed two peaks; one coincided with the period of low progesterone synthesis and delayed embryonic development, whereas the second peak coincided with regressing corpus luteum. This finding suggests that increased serum melatonin level during November–December may be responsible for delayed embryonic development by suppressing progesterone synthesis. The study showed increased melatonin receptors (MTNR1A and MTNR1B) in the corpus luteum and in the utero–embryonic unit during the period of delayed embryonic development. The in vitro study showed that a high dose of melatonin suppressed progesterone synthesis, whereas a lower dose of melatonin increased progesterone synthesis by the ovary. The effects of melatonin on ovarian steroidogenesis are mediated through changes in the expression of peripheral-type benzodiazepine receptor, P450 side chain cleavage enzyme, and LH receptor proteins. This study further showed a suppressive impact of melatonin on the progesterone receptor (PGR) in the utero–embryonic unit; this effect might contribute to delayed embryonic development in C. sphinx. The results of the present study thus suggest that a high circulating melatonin level has a dual contribution in retarding embryonic development in C. sphinx by impairing progesterone synthesis as well as by inhibiting progesterone action by reducing expression of PGR in the utero–embryonic unit.

Luteal cell steroidogenesis in relation to delayed embryonic development in the Indian short-nosed fruit bat, Cynopterus sphinx

Zoology ◽  
2009 ◽  
Vol 112 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Karukayil J. Meenakumari ◽  
Arnab Banerjee ◽  
Amitabh Krishna
Keyword(s):  
Embryonic Development ◽  
Luteal Cell ◽  
Fruit Bat ◽  
Cynopterus Sphinx
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