Hormonal induction of spawning in 4 species of frogs by coinjection with a gonadotropin-releasing hormone agonist and a dopamine antagonist.
BACKGROUND
It is well known that many anurans do not reproduce easily in captivity. Some methods are based on administration of mammalian hormones such as human chorionic gonadotropin, which are not effective in many frogs. There is a need for simple, cost-effective alternative techniques to induce spawning.


METHODS
Our new method is based on the injection of a combination of a gonadotropin-releasing hormone (GnRH) agonist and a dopamine antagonist. We have named this formulation AMPHIPLEX, which is derived from the combination of the words amphibian and amplexus. This name refers to the specific reproductive behavior of frogs when the male mounts and clasps the female to induce ovulation and to fertilize the eggs as they are laid.


RESULTS
We describe the use of the method and demonstrate its applicability for captive breeding in 3 different anuran families. We tested several combinations of GnRH agonists with dopamine antagonists using Lithobates pipiens. The combination of des-Gly10, D-Ala6, Pro-LHRH (0.4 microrams/g body weight) and metoclopramide (10 micrograms/g BWt. MET) was most effective. It was used in-season, after short-term captivity and in frogs artificially hibernated under laboratory conditions. The AMPHIPLEX method was also effective in 3 Argentinian frogs, Ceratophrys ornata, Ceratophrys cranwelli and Odontophrynus americanus.


CONCLUSIONS
Our approach offers some advantages over other hormonally-based techniques. Both sexes are injected only once and at the same time, reducing handling stress. AMPHIPLEX is a new reproductive management tool for captive breeding in Anura.
Trudeau
Vance L
VL
Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ontario K1N 6N5, Canada. trudeauv@uottawa.ca
Somoza
Gustavo M
GM
Natale
Guillermo S
GS
Pauli
Bruce
B
Wignall
Jacqui
J
Jackman
Paula
P
Doe
Ken
K
Schueler
Fredrick W
FW
D000818:Animals; D001001:Anura / Q000502:physiology*; D018492:Dopamine Antagonists / Q000008:administration & dosage* / Q000494:pharmacology; D004338:Drug Combinations; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000819:agonists* / Q000031:analogs & derivatives / Q000494:pharmacology; D007267:Injections; D008297:Male; D008787:Metoclopramide / Q000008:administration & dosage / Q000494:pharmacology; D010062:Ovulation Induction / Q000379:methods* / Q000662:veterinary; D012621:Seasons; D013045:Species Specificity
D018492:Dopamine Antagonists; D004338:Drug Combinations; C082465:LHRH ethylamide, des-Gly(10)-Ala(6)-; D007987:Gonadotropin-Releasing Hormone; D008787:Metoclopramide
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