Actions of Mammalian, Avian and Piscine Gonadotrophins in the Lizard

Abstract

The gonadotrophic activities of crude glycoprotein fractions from pituitaries of man, sheep, chicken and carp and of partially purified follicle\x=req-\ stimulating hormone (FSH) and luteinizing hormone (LH) from the three tetrapod species were examined in both sexes of the lizard Anolis carolinensis. The piscine material did not show activity in the lizard but all mammalian and avian preparations promoted spermatogenesis, ovarian growth, ovulation and steroidogenesis. FSH preparations were far more potent than LH, in fact the actions of the LH preparations may have been due largely to FSH contamination. These findings are consistent with earlier conclusions that FSH alone may be able to stimulate all types of gonadal activity in lizards, except that high doses of FSH block ovulation.Comparisons of the relative potencies of the avian and mammalian preparations provide evidence for the zoological specificity of vertebrate gonadotrophins. In general, the relative potency of chicken gonadotrophins in lizards was greater than that estimated from standard rodent bioassays: i.e. the lizard is relatively more sensitive to chicken gonadotrophin than the rodent.

PHYSIOLOGICAL ACTIONS OF HUMAN FOLLICLE-STIMULATING HORMONE AND ITS Β-Subunit IN REPTILES

“…The relatively high potency and broad actions of the highly purified hFSH in the reptiles are consistent with previous results for human and other mammalian FSH preparations. Early studies with partially purified hFSH in Anolis suggested it was more potent than ovine NIH-FSH stan¬ dard in stimulating testicular growth, but the exact potency ratio was not quantified (Licht & Stockell Hartree, 1971). The present results indicate a potency (about 530 times that of NIH-FSH-S10) that is much higher than any other vertebrate gonadotrophin tested in this lizard; other purified preparations show from about 4 to 100 times greater potency than NIH-FSH-S1 (Licht, Papkoff, Farmer, Müller, Tsui & Crews, 1977).…”

Determining the Effects of Serial Injections of Pregnant Mare Serum Gonadotropin on Plasma Testosterone Concentrations, Testicular Dynamics, and Semen Production in Leopard Geckos (Eublepharis macularius)

“…In mammals, follicle stimulating hormone (FSH) acts at the Sertoli cell to stimulate spermatogenesis, while luteinizing hormone (LH) stimulates steroidogenesis at the level of the Leydig cell. In contrast, a “one gonadotroph, two-cell” theory is generally accepted in reptiles, whereby one gonadotropin, or a gonadotropin complex, is responsible for stimulating both spermatogenesis and steroidogenesis, functions carried out by FSH and LH independently in mammals [ 19 , 23 , 24 , 33 ]. In squamates, FSH has been found to stimulate both spermatogenesis and steroidogenesis, while LH has been found to have a similar qualitative effect, although to a lesser degree [ 21 , 25 , 26 , 28 , 29 , 31 , 34 , 35 , 36 , 37 , 38 ].…”