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Hormones and Associated Compounds: NB: this section includes hormones as purified compounds, hormones in pituitaries, adjuncts, and associated compounds. Hormones are usually injected in aqueous solutions, preferably physiological salines. Some compounds require other compounds such as dimethyl suphoxide (Sigma D2438) to help them dissolve. Some studies have trailed hormones administered through the skin. However, this method has been reported as unreliable and the administered dosage is uncertain. Fine needles such as 27-30 gauge and 0.5 - 1cc syringes are best to inject the optimal volume of 100µl (0.5ml insulin syringes are particularly useful). Human Chorionic Gonadotropin (hCG) Sigma C1063. This hormone comes as a powder, which must be resuspended before administration by injection. The most convenient units are vials at 2500 or 5000 International Units (IU). The common ovulatory dose for female 50g toads is 480IU and the inducing dose for spermiation of male 35g toads is 280IU. It simplifies the process to standardize the volume for injection for both sexes with hCG alone to 100µl. Store hCG in the fridge at 4°C for short periods. Some re-suspend hormones in water but many recommend using a 'Sterile phosphate buffered water'.
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