Subject(s)
Dopamine/physiology , Pituitary Gland, Anterior/metabolism , Prolactin/metabolism , Animals , Dopamine/pharmacology , Haplorhini , Hypothalamus/analysis , Hypothalamus/physiology , In Vitro Techniques , Pituitary Gland, Anterior/blood supply , Pituitary Gland, Anterior/drug effects , Pituitary Gland, Posterior/physiology , Prolactin Release-Inhibiting Factors/blood , Prolactin Release-Inhibiting Factors/isolation & purification , Prolactin Release-Inhibiting Factors/physiology , Rats , Receptors, Dopamine/metabolismABSTRACT
Catecholamines, especially norepinephrine and dopamine, as well as GABA extracted from porcine hypothalamic tissue, were found to possess PIF activity in vitro. However, more work is needed to determine whether or not the effects of GABA or catecholamines on prolactin release are physiological or pharmacological. Until such studies are completed and until the chemical nature and biological roles of other substances with PIF activity found in the hypothalamus are clarified, no conclusion as to the nature of the physiological inhibitor of prolactin release should be made.
Subject(s)
Pituitary Gland/metabolism , Prolactin Release-Inhibiting Factors/physiology , Prolactin/metabolism , Thyrotropin-Releasing Hormone/physiology , Animals , Dopamine/pharmacology , Female , Hypothalamus/physiology , In Vitro Techniques , Male , Norepinephrine/pharmacology , Perphenazine/pharmacology , Pituitary Gland/drug effects , Prolactin Release-Inhibiting Factors/isolation & purification , Prolactin Release-Inhibiting Factors/pharmacology , Rats , Swine , Tissue ExtractsSubject(s)
Catecholamines/analysis , Hypothalamus/analysis , Prolactin Release-Inhibiting Factors/isolation & purification , Animals , Catecholamines/pharmacology , Chemical Fractionation , Chromatography , Chromatography, Gel , Chromatography, Thin Layer , Pituitary Gland/analysis , Prolactin/metabolism , Prolactin Release-Inhibiting Factors/analysis , Rats , SwineSubject(s)
Hypothalamus/analysis , Pituitary Hormone Release Inhibiting Hormones/isolation & purification , Pituitary Hormone-Releasing Hormones/isolation & purification , Animals , Biological Assay , Brain Chemistry , Gonadotropin-Releasing Hormone/analysis , Gonadotropin-Releasing Hormone/isolation & purification , Growth Hormone-Releasing Hormone/isolation & purification , MSH Release-Inhibiting Hormone/isolation & purification , Myelin Proteins/isolation & purification , Prolactin Release-Inhibiting Factors/isolation & purification , Somatostatin/isolation & purification , Thyrotropin-Releasing Hormone/isolation & purificationSubject(s)
Prolactin Release-Inhibiting Factors/isolation & purification , Prolactin/metabolism , Animals , Biological Assay , Follicle Stimulating Hormone/blood , Hypothalamus/analysis , Luteinizing Hormone/blood , Molecular Weight , Prolactin Release-Inhibiting Factors/analysis , Prolactin Release-Inhibiting Factors/immunology , Radioimmunoassay , SwineABSTRACT
Partial purification of prolactin-release stimulating factor (PRF) was performed by Sephadex G-25 gel filtration of bovine hypothalamic extracts. PRF activity was evaluated on the basis of the measurement of immunoreactive prolactin released from the isolated rat hemipituitary in vitro. PRF activity was found in the fractions with Kav=0-0.49 and prolactin-release inhibiting activity was also detected in the fractions with Kav=0.69-0.89. The dose-response relationship was established between the partially purified PRF and its activity. The elution position of the partially purified PRF preceded that of TRH on Sephadex G-25. TRH at the dose of 100 nM stimulated the release of TSH in vitro, but not the release of prolactin. These results may indicate that there exists PRF with a relatively high molecular weight in the bovine hypothalamus.