Stimulation of luteinising hormone release by luteinising hormone-releasing hormone in the porcine anterior pituitary: The role of cyclic AMP

The release of growth hormone from heifer anterior pituitary slices and the cyclic AMP content of the slices were increased by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, both increases being related to inhibitor concentration over the range 0.1–1.0mm. Neither Ba2+(6.9 or 2.3mm), K+(72mm), nor p-chloromercuribenzoate (20μm) had any effect on pituitary cyclic AMP content over a 20min period. 3-Isobutyl-1-methylxanthine potentiated the release of growth hormone in response to Ba2+(2.3mm) and K+(24mm), but the degree of potentiation did not depend on inhibitor concentration in the same way as did tissue cyclic AMP content. 3-Isobutyl-1-methylxanthine decreased the concentration of K+required to give maximum stimulation of growth-hormone release, but did not significantly increase the maximum response to Ba2+. Growth-hormone release in the presence of prostaglandin E2 (1μm) was increased by 3-isobutyl-1-methylxanthine and was inhibited by the prostaglandin antagonist, 7-oxa-13-prostynoic acid, although this antagonist increased the pituitary cyclic AMP concentration and potentiated the prostaglandin E2-induced rise in cyclic AMP content. The stimulation of growth-hormone release by p-chloromercuribenzoate was not potentiated by 3-isobutyl-1-methylxanthine. The data suggest that Ba+and K+act at the same point in the secretory process as 3-isobutyl-1-methylxanthine, although by a different mechanism, and that p-chloromercuribenzoate has a different point of action.

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STIMULATION OF PROSTAGLANDIN ACCUMULATION IN THE RAT ANTERIOR PITUITARY GLAND BY LUTEINIZING HORMONE RELEASING HORMONE IN VITRO

Journal of Endocrinology ◽

10.1677/joe.0.0750277 ◽

1977 ◽

Vol 75 (2) ◽

pp. 277-283 ◽

Cited By ~ 3

Author(s):

N. BARDEN ◽

A. BETTERIDGE

Keyword(s):

Luteinizing Hormone ◽

Cyclic Amp ◽

Anterior Pituitary ◽

Pituitary Cells ◽

Luteinizing Hormone Releasing Hormone ◽

Releasing Hormone ◽

Lh Release ◽

Lh Rh ◽

Stimulation Of

The addition of luteinizing hormone releasing hormone (LH-RH) to cultures of monolayers of rat anterior pituitary cells was shown to increase both the concentrations of prostaglandins E1 and E2 (PGE) in the cells and the release of LH over similar ranges of concentrations of LH-RH (10−6 to 10−10 mol/l). The peak concentration of PGE was observed after 2·5 h. The stimulation of the level of PGE in the cells by LH-RH was completely inhibited by two inhibitors of prostaglandin synthetase, which only partially inhibited the stimulation of LH release. Therefore the increased concentration of PGE was not obligatory for the effect of LH-RH on LH release. It was also shown that monobutyryl cyclic AMP stimulated the intracellular concentration of PGE and it is suggested that the stimulation of PGE levels may be mediated by increased levels of cyclic AMP in the cells after the addition of LH-RH.

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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

Journal of Endocrinology ◽

10.1677/joe.0.0760211 ◽

1978 ◽

Vol 76 (2) ◽

pp. 211-218 ◽

Cited By ~ 11

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.

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Stimulation of cyclic AMP accumulation in the rat anterior pituitary in vitro by analogs of luteinizing hormone-releasing hormone

Cellular and Molecular Life Sciences ◽

10.1007/bf02026341 ◽

1975 ◽

Vol 31 (4) ◽

pp. 403-404

Author(s):

W. Lippmann

Keyword(s):

Luteinizing Hormone ◽

Cyclic Amp ◽

Anterior Pituitary ◽

Luteinizing Hormone Releasing Hormone ◽

Releasing Hormone ◽

Cyclic Amp Accumulation ◽

Stimulation Of

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Stimulation of Gonadotropin-Releasing Hormone Surges by Estrogen. II. Role of Cyclic Adenosine 3′,5′-Monophosphate

Endocrinology ◽

10.1210/endo.141.4.7427 ◽

2000 ◽

Vol 141 (4) ◽

pp. 1486-1492 ◽

Cited By ~ 30

Author(s):

Patrick E. Chappell ◽

Juliet Lee ◽

Jon E. Levine

Keyword(s):

Gonadotropin Releasing Hormone ◽

Releasing Hormone ◽

Stimulation Of

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Stimulation of luteinizing hormone release from chicken pituitary cells by analogues of luteinizing hormone-releasing hormone

General and Comparative Endocrinology ◽

10.1016/0016-6480(77)90152-6 ◽

1977 ◽

Vol 32 (2) ◽

pp. 205-207 ◽

Cited By ~ 11

Author(s):

Rosemary C. Bonney ◽

F.J. Cunningham

Keyword(s):

Luteinizing Hormone ◽

Pituitary Cells ◽

Hormone Release ◽

Luteinizing Hormone Releasing Hormone ◽

Releasing Hormone ◽

Luteinizing Hormone Release ◽

Stimulation Of

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The role of insulin in the modulation of glucagon-dependent control of phenylalanine hydroxylation in isolated liver cells

Biochemical Journal ◽

10.1042/bj2420655 ◽

1987 ◽

Vol 242 (3) ◽

pp. 655-660 ◽

Cited By ~ 6

Author(s):

M J Fisher ◽

A J Dickson ◽

C I Pogson

Keyword(s):

Cyclic Amp ◽

Insulin Action ◽

Phenylalanine Hydroxylase ◽

Liver Cells ◽

Phosphorylation State ◽

Isolated Liver Cells ◽

The Impact ◽

Isolated Liver ◽

Stimulation Of

The stimulation of phenylalanine hydroxylation in isolated liver cells by sub-maximally effective concentrations of glucagon (less than 0.1 microM) is antagonized by insulin (0.1 nM-0.1 microM). This phenomenon is a consequence of a decrease in the glucagon-stimulated phosphorylation of phenylalanine hydroxylase from liver cells incubated in the presence of insulin. The impact of insulin on the phosphorylation state and activity of the hydroxylase is mimicked by incubation of liver cells in the presence of orthovanadate (10 microM). A series of cyclic AMP and cyclic GMP analogues enhanced phenylalanine hydroxylation: in each case insulin diminished the stimulation of flux. These results are discussed in the light of the characteristics of insulin action on other metabolic processes.

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Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

AJP Cell Physiology ◽

10.1152/ajpcell.1979.237.5.c200 ◽

1979 ◽

Vol 237 (5) ◽

pp. C200-C204 ◽

Cited By ~ 11

Author(s):

D. J. Stewart ◽

J. Sax ◽

R. Funk ◽

A. K. Sen

Keyword(s):

Cyclic Amp ◽

Guanylate Cyclase ◽

Cyclic Gmp ◽

Salt Gland ◽

Domestic Ducks ◽

Stimulus Secretion Coupling ◽

Stimulation Of

Stimulation of salt galnd secretion in domestic ducks in vivo increased the cyclic GMP concentration of the tissue, but had no effect on cyclic AMP levels. Methacholine, which is known to stimulate sodium transport by the glands both in vivo and in vitro, stimulated ouabain-sensitive respiration in salt gland slices. Cyclic GMP stimulated ouabain-sensitive respiration to the same extent as methacholine. Guanylate cyclase stimulators, hydroxylamine and sodium azide, also stimulated ouabain-sensitive respiration. The stimulation of ouabain-sensitive respiration by methacholine was blocked either by atropine or by removal of calcium from the incubation medium. The stimulation of ouabain-sensitive respiration by cyclic GMP still occurred in the absence of calcium. The above observations seem to indicate that cyclic GMP acts as a tertiary link in the process of stimulus-secretion coupling in the tissue.

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Physiological role of galanin in the regulation of anterior pituitary function in humans

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1994.266.1.e57 ◽

1994 ◽

Vol 266 (1) ◽

pp. E57-E61 ◽

Cited By ~ 4

Author(s):

A. Giustina ◽

M. Licini ◽

M. Schettino ◽

M. Doga ◽

G. Pizzocolo ◽

...

Keyword(s):

Anterior Pituitary ◽

Physiological Role ◽

Thyroid Stimulating Hormone ◽

Pituitary Function ◽

Slight Reduction ◽

Baseline Serum ◽

Releasing Hormone ◽

Anterior Pituitary Function ◽

Stimulating Hormone

The aim of our study was to elucidate the physiological role of the neuropeptide galanin in the regulation of anterior pituitary function in human subjects. Six healthy men (age range 26-35 yr, body mass index range 20-24 kg/m2) underwent in random order 1) an intravenous bolus injection of growth hormone-releasing hormone (GHRH)-(1-29)-NH2 (100 micrograms) + thyrotropin-releasing hormone (TRH, 200 micrograms) + luteinizing hormone-releasing hormone (LHRH, 100 micrograms) + corticotropin-releasing hormone (CRH, 100 micrograms), and 2) intravenous saline (100 ml) at time 0 plus either human galanin (500 micrograms) in saline (100 ml) or saline (100 ml) from -15 to +30 min. Human galanin determined a significant increase in serum GH (GH peak: 11.3 +/- 2.2 micrograms/l) from both baseline and placebo levels. No significant differences were observed between GH values after galanin and those after GHRH alone (24.3 +/- 5.2 micrograms/l). Human galanin significantly enhanced the GH response to GHRH (peak 49.5 +/- 10 micrograms/l) with respect to either GHRH or galanin alone. Human galanin caused a slight decrease in baseline serum adrenocorticotropic hormone (ACTH; 16.3 +/- 2.4 pg/ml) and cortisol levels (8 +/- 1.5 micrograms/dl). Galanin also determined a slight reduction in both the ACTH (peak 27 +/- 8 pg/ml) and cortisol (peak 13.8 +/- 1.3 micrograms/dl) responses to CRH. Baseline and releasing hormone-stimulated secretions of prolactin, thyroid-stimulating hormone, LH, and follicle-stimulating hormone were not altered by galanin. Our data suggest a physiological role for the neuropeptide galanin in the regulation of GH secretion in humans.(ABSTRACT TRUNCATED AT 250 WORDS)

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