Immunochemical studies on the pituitary gonadotropins (FSH and LH) from the bullfrog, Rana catesbeiana

Daniels, Ellen L.; Licht, Paul; Farmer, Susan Walker; Papkoff, Harold

doi:10.1016/0016-6480(77)90145-9

Cited by 42 publications

(10 citation statements)

References 11 publications

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“…Several (Florkin, 1966). Or, de nombreux travaux ont confirmé l'hypothèse émise par Fontaine (1967) Crim, 1979 ;Licht, 1979 (Licht et Bona-Gallo, 1978 Licht et al, 1977 ; (Burzawa-Gérard, 1974b).…”

unclassified

“…En collaboration avec P. et J. Jolles, nous avons pu déterminer la séquence partielle de chacune des sous-unités au N-terminal (Jolles et al, 1977 (Papkoff et al,1976 ;Licht et al, 1977. L'ensemble de ces données suggère que la sous-unité p joue un rôle prépondérant dans le déterminisme de la spécificité zoologique d'action des ensembles «p, comme elle le fait pour la spécificité fonctionnelle (Pierce et al, 1971 (Licht et al, 1977 ;Licht, 1978) (Marchelidon et al, 1978(Marchelidon et al, , 1979 (Peter, 1978).…”

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“…L'ensemble de ces données suggère que la sous-unité p joue un rôle prépondérant dans le déterminisme de la spécificité zoologique d'action des ensembles «p, comme elle le fait pour la spécificité fonctionnelle (Pierce et al, 1971 (Licht et al, 1977 ;Licht, 1978) (Marchelidon et al, 1978(Marchelidon et al, , 1979 (Peter, 1978). L'aestradiol stimule chez l'anguille les cellules gonadotropes hypophysaires (Olivereau et Chambolle, 1978).…”

unclassified

“…L'activité protéine kinase (PK) a également été étudiée ; la c-G T H a seulement un effet très faible, in vitro, sur la PK d'ovaire de cyprin. Une différence similaire existe en ce qui concerne l'action de l'AMPc lui-même (10-6 M) sur la PK d'homogénats ovariens ; en présence de théophylline, la PK est multipliée par 5-6 chez le rat mais ne varie pas chez l'anguille ; en absence de théo-phylline, l'AMPc induit une augmentation significative, mais faible, de la PK de l'ovaire d'anguille Fontaine-Bertrand, données Fontaine et al, 1972 ;Breton et al, 1973 ;Fontaine, 1975 (Fontaine, 1969) Licht et al, 1977). Les (Licht et al,1977 (Licht et Midgley,1976 (Licht et al, 1977 (Brown et al, 1975 ;Ishü et Furuya, 1975 (Burns, 1972 (Licht et al,1977 (Licht et al,1977 ;Maung et Follett, 1977 ;Jenkins et al, 1978).…”

unclassified

“…Une certaine spécificité des FSH mammaliennes est également indiquée. Ces hormones, mais non les LH inhiben t en effet la liaison de la l2s l h-FSH ou de la l2s l r-FSH à des testicules d'Oiseaux (Licht et al,1977 ;lshii et Adachi, 1977 de Fontaine et al, 1973 ;Thibault, 1977 ;Eshkol et Lunenfeld, 1977 ;Zeleznik et al, 1977 ;Tsafriri et Lindner, 1978 ;Haour et Saez, 1978 Papkoff,1977). Sur l'adényl cyclase (AC) d'ovaires de rat, la c-GTH (jusqu'à 330 V .…”

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Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Fontaine¹

1980

Reprod. Nutr. Dévelop.

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findings and demonstrated that, from fish to mammals, the antigenic determinants were better conserved for LH! than for the rx subunits. An hybrid molecule, formed by associating bovine LHa and c-GTHp, was more active in frogs than either of the mother-hormones, while it was inactive on adenylate cyclase in homogenates of rat or goldfish ovaries. This hybrid, however, was as active as c-GTH in increasing c-AMP concentration in pieces of eel ovary. Interestingly, sturgeon gonadotropin (aci-GTH) had somewhat similar biological properties. Aci-GTH subunits were partially purified, and an hybrid (bovine LHa-aci-GTH(3) was created. Both of the possible hybrids from the c-GTH and aci-GTH subunits could also be formed.The kinetics of subunit association have been studied in vitro. As compared with the formation of ovine LH, that of c-GTH was more rapid and less thermodependent. Thus, even though fish may live at low temperatures, GTH synthesis proceeds at a reasonable rate. The thermodependence of the formation of the hybrid, bovine LHa-c-GTHp, was identical to that of the c-GTH. Therefore, the subunit alone seems to determine thermodependence.

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Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Fontaine¹

1980

Reprod. Nutr. Dévelop.

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Environmental influence on testicular activity in the green frog, Rana esculenta

et al. 1978

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Adult male Rana esculenta were placed under several combinations of light and temperature in different periods of the year to elucidate the regulation of various testicular phases by environmental factors and to discover the mechanism through which these factors act upon the testis. In nature the quiescence of spermatogenesis in winter is due solely to low temperature. Under controlled experimental conditions a temperature of 4"C, whatever the photoperiod, impairs spermatogenesis at any time of the year. The early spring resurgence of a new wave of spermatogenesis depends upon a gradual rise both in the environmental temperature and the photoperiod. In fact in nature the temperature range favorable for active spermatogenesis is between 12°C and 25°C with a period of between 10 and 16 hours of light daily. In the laboratory a temperature of ca. 20°C and a period of 12 hours of light daily represent the best combination of these factors for regulating and maintaining active spermatogenesis in any period of the year. Very long (21 hours of light daily) and very short (3 hours of light daily) photoperiods, however, have deleterious effects upon the testis. These effects are manifested mainly in the suppression of primary spermatocytes and successively in a gradual decline in number of secondary spermatocytes and spermatids and appearance of numerous degenerating cell nests. The same occurs when the frogs are treated a t very low temperature. Besides this, high temperature stimulates plasma levels of testosterone which does not occur if the animals are kept in the dark. Very low temperature, on the other hand, has the opposite effect. These data suggest that a combination of "critical temperature" and "critical photoperiod" is necessary for regulating and maintaining active spermatogenesis since neither of these factors is effective in the absence of the other. The stimulatory effects of high temperature are due to the increased secretory activity of the pituitary gonadotropin.Furthermore the present results also indicate that the testis of Rana esculenta does not manifest any seasonal change in the degree of its response to thermal and/or photoperiodic regulation i.e., it does not show photo-or thermal refractoriness during the year.As cold-blooded vertebrates amphibians are greatly susceptible to environmental fluctuations. In fact most of the anurans and urodeles exhibit a markedly seasonal testicular cycle (circannual) (Lofts, '74; Rastogi, '76a).Three major environmental factors have been implicated in the amphibian breeding cycle: rainfall, photoperiod and temperature. Rainfall has thus far been shown to influence

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In vitro exposure of frog (Rana pipiens) pituitaries to gonadotropin‐releasing hormone results in a persistent stimulation of gonadotropin biosynthesis

Stamper

Licht

1993

J. Exp. Zool.

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To further investigate the action of gonadotropin-releasing hormone (GnRH) on gonadotropin (Gth) secretion and synthesis, pituitaries from frogs, Rana pipiens, were incubated in the presence or absence of 100 ng/ml GnRH for 12 h. GnRH was then removed from the medium and glands were labeled with 35S-methionine either 12, 24, or 36 h after the conclusion of GnRH exposure. Immunoassayable LH and FSH (iLH and iFSH; both labeled and nonlabeled hormone) were determined by separate radioimmunoassays. Newly synthesized (radiolabeled) Gth was quantified by immunoprecipitation. When GnRH was present in the medium, it stimulated the secretion of both iLH and iFSH (compared to unexposed glands). Following withdrawal of the secretagogue, iLH and iFSH secretion diminished until they returned to control levels (within ca. 12 h). Previous exposure to GnRH enhanced the biosynthesis of Gth; this elevation was detectable up to 36 h after removal of the secretagogue. The magnitude of the elevation in Gth synthesis did not diminish with time, as secretion had, but remained constant. Gth synthesis was comparable in glands that had been exposed to GnRH 12 h and those exposed to the secretagogue 36 h prior. Thus, the GnRH-induced elevation in Gth secretion and synthesis can be dissociated; the elevation in synthesis is more chronic than the elevation in secretion.

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Immunochemical studies on the pituitary gonadotropins (FSH and LH) from the bullfrog, Rana catesbeiana

Cited by 42 publications

References 11 publications

Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Environmental influence on testicular activity in the green frog, Rana esculenta

In vitro exposure of frog (Rana pipiens) pituitaries to gonadotropin‐releasing hormone results in a persistent stimulation of gonadotropin biosynthesis

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