18. Pregnancy Endocrinology 2010

18. Pregnancy Endocrinology 2010 - Endocrinology of...

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Unformatted text preview: Endocrinology of Pregnancy Gravidity - oviparous species retain egg for species specific period time defined by: length of shelling process oviposition timed to environmental event oviposition is under control of mother Oviparous reptiles Egg retention associated with corpus luteum activity remove CL early in gravidity and spontaneous oviposition (e.g., lizards.snakes) at ovulation, CL formed by luteinization of granulosa and thecal cells CL & Progesterone surge in progesterone observed remains elevated in some species others it is elevated only at ovulation Post-ovulation movement of egg down reproductive tract associated with synthesis of PGF 2 activity present for short period period of albumen and shell fiber secretion associated with -adrenergic stimulation oviduct contraction then becomes quiescent inhibition of -adrenergic stimulation PG synthesis Oviposition I egg retention can last a few days or months oviposition preceded by/associated with luteolysis PGF 2 induces luteolysis in two lizard species Oviposition II uterine contraction associated with: 1. PGF 2 potent smooth muscle contractor exogenous injection induces oviposition elevated during natural oviposition sea turtles & tuatara birds Oviposition III 2. Arginine Vasotocin (AVT) octapeptide from neurohypophysis potent smooth muscle contractor exogenous injection induces oviposition elevated during natural oviposition sea turtle & tuatara 3. -adrenergic stimulation blockers inhibit oviposition Lizards, birds Cervical Relaxation Relaxin- peptide hormone from CL augments timing of uterine contraction in turtle removal of CL late in gravidity inhibits oviposition in birds and reptiles - role unknown? PGE 2 synthesis increases just prior to oviposition exogenous injection does not induce oviposition Elevated at oviposition in sea turtle, tuatara, birds Albumen -adrenergic Progesterone Fibers Calcium PGF 2 Ovulation AVT Progesterone - adrenergic PGF 2 Estradiol Relaxin PGE 2 Oviposition Oviposition or nesting behavior observed in many species can be induced by PGF 2 fish spawning behavior lizard oviposition behavior pig "nesting" behavior kangaroo belly licking behavior Birth Gastric brooding frog (extinct 1980s) swallow fertilized eggs embryo and tadpoles synthesize PGE 2 inhibits gastric secretion during time in stomach! Gastrotheca - marsupial frog AVT induces 'birth' - Induces female leg movements which include wiping-out the pouch Mammalian Pregnancy viviparous eutherian mammal unlike oviparous model pregnancy length and establishment due to embryonic signals like oviparous model CL plays important role in many species In humans CL dies after 10-14 days unless rescued CL rescued by...
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This note was uploaded on 05/19/2011 for the course ZOO 4926 taught by Professor Staff during the Summer '08 term at University of Florida.

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18. Pregnancy Endocrinology 2010 - Endocrinology of...

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