Partial Purification and Characterization of Chicken and Rat Follicle Stimulating Hormone-Releasing Factors

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Abstract
Chicken and rat follicle stimulating hormone-releasing factors (FRF) were partially purified and their behavior on chromatographic columns was compared. Extracts of hypothalami were purified by ultrafiltration and chromatography on Sephadex G-25 and CM-Sephadex C-25. Columns were monitored by optical density (254 mμ) and vasopressor assay. FRF activity was evaluated by release of follicle stimulating hormone (FSH) from rat adenohypophyses in vitro, and FSH was assayed by radioimmunoassay. The elution patterns of rat and chicken FRF were not distinguishable on Sephadex (Rf 1.89–2.09), but were clearly different on the ion-exchange column. Chicken FRF repeatedly emerged at tubes 10–20. There was a significant linear relationship between the dose of avian FRF and the release of FSH. Rat FRF activity emerged primarily in tubes 31–40, although there was some in tubes 21–30. When rat and chicken FRF fractions from Sephadex were mixed and then run on CM-Sephadex, two distinct areas of activity emerged in tubes 13–22 and 30–43. Fractions from CM-Sephadex columns containing FRF activity were devoid of pressor activity. The FRF of both chicken and rat hypothalamic extracts emerged from columns in the same fractions as the luteinizing hormone-releasing factor (LRF) of those species. These data demonstrate the existence of an avian FRF, show that avian and rat FRFs are not identical, and suggest that similar compounds are responsible for LRF and FRF activities in each of these species. (Endocrinology91: 1090, 1972)

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