Differences in luteinizing hormone release stimulated in rat anterior pituitary cells by leukotriene C4 and by gonadotropin-releasing hormone in vitro

Summary Continuous administration of leukotriene C₄ (LTC₄, 10^–10 M) to superfused rat anterior pituitary cells increased LH release for 40 min only, whereas in a parallel experiment gonadotropin-releasing hormone (GnRH, 10^–9 M) evoked a continuous increase in hormone secretion. In contrast to GnRH, LTC₄ did not desensitize rat anterior pituitary cells. The secretory action resulting from the administration of LTC₄ (10^–10 M) was abolished for 40 min after previous stimulation. The results documented the dual action of LTC₄ on LH exocytosis.     

Differences in luteinizing hormone release stimulated in rat anterior pituitary cells by leukotriene C4 and by gonadotropin-releasing hormone in vitro

Continuous administration of leukotriene C4 (LTC4, 10(-10) M) to superfused rat anterior pituitary cells increased LH release for 40 min only, whereas in a parallel experiment gonadotropin-releasing hormone (GnRH, 10(-9) M) evoked a continuous increase in hormone secretion. In contrast to GnRH, LTC4 did not desensitize rat anterior pituitary cells. The secretory action resulting from the administration of LTC4 (10(-10) M) was abolished for 40 min after previous stimulation. The results documented the dual action of LTC4 on LH exocytosis.     

Somatostatin inhibits in vitro release of luteinizing hormone releasing hormone from rat mediobasal hypothalamic slices

Summary Somatostatin, in concentrations ranging from 10^–10 M to 10^–7 M, induces a dose-dependent inhibition of LHRH release from mediobasal hypothalamic slices incubated in vitro. In contrast, VIP, secretin, glucagon, substance P, neurotensin and arginine-vasotocin do not affect spontaneous release of LHRH.     

A depolymerizing effect of the luteinizing hormone and follicle stimulating hormone on the neurotubules of the hypothalamus-hypophysial tract in the rat

Résumé Les neurotubules des fibres nerveuses du tract hypothalamo-hypophysaire du rat sont désorganisées après des traitments in vitro avec l'hormone lutéinisante et l'hormone folliculaire stimulante. Le méchanisme de dépolymérisation est discuté.     

Cyclic variations in luteinizing and follicle stimulating hormone excretion by male rabbits,indicating a male equivalent to the oestrous cycle

Summary Cyclic variations of the urinary concentrations of gonadotropins in the male rabbit have been demonstrated. The mean durations of the cycles, 5–7 days, are close to that of the oestrous cycle of the female rabbit.     

Effect of synthetic luteinizing hormone releasing hormone on pituitary and serum levels of luteinizing hormone of intact and median eminence lesioned male rats

Résumé Des rats mâles intacts ou ayant une lésion du ME ont reçu une seule injection intrajugulaire de LRF synthétique. Les variations de taux de LH hypophysaire et sérique (en fonction du temps et de la dose réponse) montrent que le LRF contrôle la sécrétion (la décharge et la synthèse) du LH hypophysaire.     

An in vivo method for evaluating the hypothalamic follicle stimulating hormone releasing factor

Résumé L'injection intracarotidienne d'extraits hypothalamiques est suivie chez le rat d'une chute significative des taux de FSH à niveau hypophysaire. Ce phénomène se vérifie déjà 20 min après l'injection et est proportionnel à la dose d'hypothalamus injecté.     

Sequence comparison of human pituitary growth hormone,human chorionic somatomammotropin and ovine pituitary lactogenic hormone

Zusammenfassung Ein Vergleich der Aminosäuresequenzen von menschlichen Wachstumshormonen und menschlichem Chorion-Somatomammotropin mit denjenigen von Prolactin zeigt, dass 26% des Rückstandes in allen drei Molekülen die gleiche Position hatten mit zusätzlichen 34% als möglichen Ersatz. Alle drei Hormone scheinen einen gleichen Ursprung zu haben.     

Induction of hyperlipidemia by human thyroid stimulating hormone immunization in rabbits

Summary In our study we are able to demonstrate that with TSH booster and bleeding animals 10–20 days post immunization, when rabbits have increased in antibody titer, there is an increase in cholesterol and triglyceride. These findings are suggestive that most probably we are rendering these rabbits hypothyroid.Acknowledgments. The authors are indebted to Miss J. Meister for her skillful technical help. We are also indebted to the National Institute of Arthritis, Metabolism, and Digestive Diseases for Human Thyroid Stimulating Hormone for iodination.