CHANGES IN PROTEIN SYNTHESIS IN THE BRAIN AND ANTERIOR PITUITARY GLAND DURING THE OESTROUS CYCLE, AND THEIR APPARENT RELATION TO VARIATIONS IN PLASMA LH LEVELS

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S29
Author(s):  
Pamela C. B. MacKinnon ◽  
M. B. ter Haar
Keyword(s):  
Protein Synthesis ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
The Brain

Relationship between endogenous opioids and the oestrous cycle in the rat

1984 ◽  
Vol 100 (3) ◽  
pp. 271-275 ◽  
Author(s):  
G. K. Hulse ◽  
G. J. Coleman ◽  
D. L. Copolov ◽  
J. A. Clements
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Ovarian Hormones ◽  
Endogenous Opioids ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Neurointermediate Lobe ◽  
Response To Stress ◽  
Induced Changes

ABSTRACT The aim of this study was twofold: (1) to document changes in levels of immunoreactive β-endorphin (Ir-β-EP) in the hypothalamus, anterior pituitary gland, neurointermediate lobe and plasma during the oestrous cycle of the rat and (2) to investigate stress-induced changes in plasma Ir-β-EP at different stages of the oestrous cycle. Evidence was found that Ir-β-EP levels in the hypothalamus, anterior pituitary gland and plasma are not constant during the oestrous cycle and that the Ir-β-EP response to stress is a function of the phase of the oestrous cycle at which stress is applied. It is suggested that fluctuations in ovarian hormones may influence oestrous Ir-β-EP levels both under normal conditions and after exposure to stress. J. Endocr. (1984) 100, 271–275

Ornithine decarboxylase activity and polyamines in the anterior pituitary gland during the rat oestrous cycle

1985 ◽  
Vol 107 (1) ◽  
pp. 83-87 ◽  
Author(s):  
L. Persson ◽  
M. Nilsson ◽  
E. Rosengren
Keyword(s):  
Pituitary Gland ◽  
Ornithine Decarboxylase ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Ovariectomized Rats ◽  
Oestrogen Treatment ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Releasing Hormone

ABSTRACT The biosynthesis of polyamines, an ubiquitous group of amines shown to be essential for normal cellular growth and differentiation, was studied in the rat anterior pituitary gland during the different stages of the oestrous cycle. The activity of ornithine decarboxylase (ODC), which catalyses the rate-limiting step in the biosynthesis of polyamines, was low during oestrus, metoestrus and dioestrus. However, a marked transitory rise in ODC activity was found in the pituitary gland on the evening of pro-oestrus. The rise in ODC activity was accompanied by an increase in the pituitary content of the polyamines putrescine and spermidine. Ovariectomy did not significantly change the basal ODC activity in the pituitary gland. Oestrogen treatment of ovariectomized rats resulted in a marked stimulation of pituitary polyamine biosynthesis. The largest effects were observed when oestrogen was given as two injections 72 h apart, which gave rise to levels of ODC activity comparable to those observed on the evening of pro-oestrus. The increase in polyamine synthesis in the anterior pituitary gland during pro-oestrus appeared not to be related to the preovulatory secretion of LH or prolactin, since neither LH-releasing hormone nor thyrotrophin-releasing hormone (which induces a secretion of prolactin) affected pituitary ODC activity. The observed biosynthesis of polyamines may be associated with the cellular proliferation which occurs in the anterior pituitary gland at oestrus. J. Endocr. (1985) 107, 83–87

OESTRADIOL RECEPTORS IN THE RAT ANTERIOR PITUITARY GLAND DURING THE OESTROUS CYCLE: QUANTITATION OF RECEPTOR ACTIVITY IN RELATION TO GONADOTROPHIN RELEASING HORMONE-MEDIATED LUTEINIZING HORMONE RELEASE

1978 ◽  
Vol 76 (2) ◽  
pp. 211-218 ◽  
Author(s):  
K. K. SEN ◽  
K. M. J. MENON
Keyword(s):  
Pituitary Gland ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Hormone Release ◽  
Releasing Hormone ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone ◽  
Stimulation Of

Specific oestradiol binding to a receptor in nuclear and cytosol fractions of the rat anterior pituitary gland and pituitary responsiveness to gonadotrophin releasing hormone (GnRH) during the oestrous cycle have been studied. To accomplish this, both unoccupied and occupied oestradiol-binding sites in the cytosol and oestradiol-binding sites in the nucleus and total cell were measured during the oestrous cycle. The concentration of unoccupied and occupied sites and total oestradiol binding in the cytosol fluctuated during the cycle. At pro-oestrus, the concentration of cytosol receptor was diminished by about 40% and replenishment occurred during oestrus. On the other hand, a profound increase in concentrations of cellular and nuclear receptors occurred at pro-oestrus. Administration of GnRH significantly stimulated LH release at all stages of the cycle. The maximum stimulation of LH release by GnRH was observed at 13.00 h of pro-oestrus. From these studies, it is concluded that pituitary responsiveness to exogenous GnRH during pro-oestrus parallels the changes in the content of oestrogen receptors in the cytosol and nucleus.

Effect of stress on tissue and plasma levels of immunoreactive β-endorphin in ovariectomized rats primed with oestrogen and progesterone

1984 ◽  
Vol 100 (3) ◽  
pp. 277-280 ◽  
Author(s):  
G. K. Hulse ◽  
G. J. Coleman
Keyword(s):  
Pituitary Gland ◽  
Plasma Levels ◽  
Anterior Pituitary ◽  
Sesame Oil ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Ovariectomized Rats ◽  
Neurointermediate Lobe ◽  
Pituitary Tissue

ABSTRACT The aim of this study was to investigate the effect of oestrogen and progesterone on levels of immunoreactive β-endorphin (Ir-β-EP) in the hypothalamus, anterior pituitary gland, neurointermediate lobe and plasma under normal conditions and conditions of stress. The injection of oestrogen + progesterone into ovariectomized rats increased Ir-β-EP levels in extracts of anterior pituitary tissue and in plasma, under both normal and stressed conditions. Exposure to a stress reduced the content of anterior pituitary Ir-β-EP in ovariectomized rats treated with oestrogen + progesterone and also with sesame oil. Such treatment only resulted in increments in plasma Ir-β-EP in oil-treated but not in oestrogen + progesterone-treated overiectomized rats. It was concluded (1) that oestrogen and progesterone are involved in the regulation of resting levels of anterior pituitary Ir-β-EP during the rat oestrous cycle, (2) that stress reduces levels of anterior pituitary Ir-β-EP and (3) that increased levels of plasma oestrogen + progesterone inhibit plasma Ir-β-EP increments which normally accompany exposure to stress. J. Endocr. (1984) 100, 277–280

Alteration by thyrotrophin-releasing hormone of heterogeneous components associated with thyrotrophin biosynthesis in the rat anterior pituitary gland

1984 ◽  
Vol 103 (2) ◽  
pp. 165-171 ◽  
Author(s):  
M. Mori ◽  
M. Murakami ◽  
T. Iriuchijima ◽  
H. Ishihara ◽  
I. Kobayashi ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
De Novo ◽  
Close Association ◽  
Anterior Pituitary Gland ◽  
Male Rats ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Pituitary Glands

ABSTRACT An influence of thyrotrophin-releasing hormone (TRH) on TSH heterogeneity in close association with de-novo biosynthesis was studied in rat anterior pituitary glands. Hemipituitary glands from adult male rats were incubated in Krebs–Henseleit–glucose media containing [3H]glucosamine and [14C]alanine for 3 and 6 h in the presence or absence of 10 ng TRH per ml. Fractions of TSH in the pituitary extracts were obtained using affinity chromatography coupled with an anti-rat TSH globulin. These TSH fractions were analysed by isoelectric focusing. The control pituitary glands were composed of four component peaks (isoelectric point (pI) 8·7, 7·8, 5·3 and 2·5) of [3H]glucosamine and [14C]alanine incorporated into TSH, and the amounts of radioactivity of these components were increased with the incubation time. Of these peaks, radioactive components of pI 8·7 and 7·8 coincided with the non-radioactive TSH components measured by radioimmunoassay. Addition of TRH increased incorporation of [14C]alanine into TSH in each of the components to a greater extent than that of [3H]glucosamine. In addition, new components with pI 7·2, 6·5 and 6·2, each component corresponding to each unlabelled TSH component, were demonstrated in the presence of TRH. Because addition of TRH did not change the amounts of [14C]alanine-labelled TSH in the media, the newly formed components were assumed to be connected with protein synthesis occurring in the anterior pituitary gland, which may be specific substances in response to TRH administration. These results indicate that TRH principally elicits an increase in protein synthesis in TSH at the anterior pituitary level, resulting in an alteration of TSH heterogeneity. J. Endocr. (1984) 103, 165–171

scholarly journals 60 YEARS OF NEUROENDOCRINOLOGY: MEMOIR: Harris' neuroendocrine revolution: of portal vessels and self-priming

2015 ◽  
Vol 226 (2) ◽  
pp. T13-T24 ◽  
Author(s):  
George Fink
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Portal Blood ◽  
Endocrine Disorders ◽  
Experimental Proof ◽  
Chemical Substances ◽  
Major Interest ◽  
The Brain ◽  
Hypophysial Portal

Geoffrey Harris, while still a medical student at Cambridge, was the first researcher (1937) to provide experimental proof for the then tentative view that the anterior pituitary gland was controlled by the CNS. The elegant studies carried out by Harris in the 1940s and early 1950s, alone and in collaboration with John Green and Dora Jacobsohn, established that this control was mediated by a neurohumoral mechanism that involved the transport by hypophysial portal vessel blood of chemical substances from the hypothalamus to the anterior pituitary gland. The neurohumoral control of anterior pituitary secretion was proved by the isolation and characterisation of the ‘chemical substances’ (mainly neuropeptides) and the finding that these substances were released into hypophysial portal blood in a manner consistent with their physiological functions. The new discipline of neuroendocrinology – the way that the brain controls endocrine glands andvice versa– revolutionised the treatment of endocrine disorders such as growth and pubertal abnormalities, infertility and hormone-dependent tumours, and it underpins our understanding of the sexual differentiation of the brain and key aspects of behaviour and mental disorder. Neuroendocrine principles are illustrated in this Thematic Review by way of Harris' major interest: hypothalamic–pituitary–gonadal control. Attention is focussed on the measurement of GnRH in hypophysial portal blood and the role played by the self-priming effect of GnRH in promoting the onset of puberty and enabling the oestrogen-induced surge or pulses of GnRH to trigger the ovulatory gonadotrophin surge in humans and other spontaneously ovulating mammals.

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