Reproductive Endocrinology of Amphibians

Abstract

Amphibians have the same basic repertoire of reproductive hormones as other vertebrates. For example, their hypothalamus synthesizes a decapeptide that is structurally and functionally similar to the gonadotropin-releasing hormone (LH-RH) of mammals. LH-RH stimulates the pituitary gland of amphibians to release two distinct gonadotropins, referred to as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) after the homologous mammalian gonadotropins. The gonadotropins travel through the blood to the gonads and stimulate gametogenesis and the synthesis of steroid hormones (progesterone, 17$β$-estradiol, testosterone, and 5α-dihydrotestosterone). Despite similarities between the reproductive hormones of mammals and amphibians, amphibians are not simply hairless laboratory rats. In many respects, the reproductive endocrinology of amphibians is interesting and unique.