The endocrine factors concerned in the control of the ovarian cycle

Abstract

EXPERIMENTAL studies upon the relation of the pituitary gland to the ovarian cycle in mammals involve three principal difficulties: (i) that of removing the pituitary itself without injury to the animal; (ii) the practical impossibility of removing the anterior lobe without removing or damaging the posterior lobe; (iii) the necessity of killing the' test animal, in most cases, to confirm whether injected extracts or transplants have produced ovulation or other changes in the ovaries. None of these objections arises, however, in the case of certain amphibia. In a recent series of papers by Hogben [1930], Hogben, Charles and Slome [1931] and Zwarenstein and Shapiro [1933] reporting work carried out on the African Clawed Toad (Xenopu8s laevis) it has been shown: (i) that ovarian atrophy follows removal of the anterior lobe alone; (ii) that injection of acid extracts prepared by the method elsewhere described by the writer [Bellerby, 1929] will induce the extrusion of eggs during the period of the year when the anirmal does not breed either in its natural

Pregnancy Diagnosis

“…Bellerby (1933) confirmed these observations, and showed that Xenopus injected with alp will lay eggs even outside the normal breeding season. Bellerby (1934) and Shapiro & Zwarenstein (1934) reported on the successful use of Xenopus for the diagnosis of pregnancy.…”

The influence of the gonads on protein metabolism

“…Extracts of brain and liver prepared by the same method were injected as controls. Pituitary extracts were prepared from sheep anterior lobe according to Bellerby [1933] and extracts of brain and liver were used as controls. Saline suspensions of testes and brain were prepared from ram's tissues as described previously [Schrire & Zwarenstein, 1932, 2].…”

An Interspecies Heart-to-Heart: Using Xenopus to Uncover the Genetic Basis of Congenital Heart Disease

“…Xenopus breeding is possible year-round (36,37), with large clutch sizes, up to 2000 eggs per day per frog, and easy in vitro fertilization providing researchers with a large continuous set of developmentally synchronized embryos (38). These embryos develop externally and are therefore easily visible and accessible for microinjection-based genetic manipulations.…”