Prolactin and growth hormone secretion in chickens: stimulation by histamine and inhibition by gamma-aminobutyric acid

1984 ◽  
Vol 107 (1) ◽  
pp. 36-41 ◽  
Author(s):  
T. R. Hall ◽  
S. Harvey ◽  
A. Chadwick
Keyword(s):  
Growth Hormone ◽  
Direct Effect ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Gh Secretion ◽  
Pituitary Glands ◽  
Stimulation By Histamine

Abstract. Anterior pituitary glands from chickens (Gallus domesticus) were incubated with or without single, mediobasal chicken hypothalami in medium containing histamine, alone or together with the antagonist diphenhydramine or in medium containing gamma-aminobutyric acid (GABA), alone or together with the antagonists bicuculline or picrotoxin. The release of prolactin (Prl) and growth hormone (GH) was measured by homologous radioimmunoassay. Histamine had no direct effect on the release of either hormone but stimulated Prl (in a dose-related way) and GH release when anterior pituitary glands were co-incubated with hypothalami. Diphenhydramine also had no direct effect on Prl or GH secretion but blocked the stimulatory effect of histamine on hypothalamusinduced Prl and GH release. When anterior pituitary glands were incubated without hypothalami, GABA, bicuculline and picrotoxin had no effect on the release of Prl or GH. However, GABA inhibited the release of both hormones in a concentration-related manner, when anterior pituitary glands were co-incubated with hypothalami. This inhibition was blocked by both bicuculline and picrotoxin. These results suggest that histamine and GABA may be involved in controlling the secretion of Prl and GH from the avian pituitary gland, possibly by modifying the secretion of hypothalamic releasing and/or release-inhibiting hormones.

INVOLVEMENT OF GROWTH HORMONE-RELEASING FACTOR IN GROWTH HORMONE SECRETION INDUCED BY GAMMA-AMINOBUTYRIC ACID IN CONSCIOUS RATS

Endocrinology ◽  
1985 ◽  
Vol 117 (2) ◽  
pp. 787-789 ◽  
Author(s):  
Yoshio Murakami ◽  
Yuzuru Kato ◽  
Yasuhiro Kabayama ◽  
Katsuyoshi Tojo ◽  
Tatsuhide Inoue ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Growth Hormone Releasing Factor ◽  
Conscious Rats

Growth hormone-releasing factor-induced growth hormone secretion from perifused rat anterior pituitary cells: lack of influence of glucose concentration, and normal responses in pituitary cells from diabetic animals

1989 ◽  
Vol 122 (3) ◽  
pp. 657-660 ◽  
Author(s):  
G. Caldwell ◽  
G. Hart ◽  
E. M. Kohner ◽  
J. M. Burrin
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Initial Response ◽  
Diabetic Rats ◽  
Pituitary Cells ◽  
Gh Secretion ◽  
Anterior Pituitary Cells ◽  
Streptozotocin Induced Diabetes

ABSTRACT The mechanism responsible for the suppression of GH secretion in hyperglycaemia and hypoglyceamia in rats has been investigated using perifusion of anterior pituitary cells. When perifused with Krebs-Ringer bicarbonate containing normal (5 mmol/l), high (20 mmol/l) and low (1 mmol/l) concentrations of glucose, the GH responses to GH-releasing factor (GRF) were 85 ± 5, 85·5 ± 5·4 and 89 ± 3·0 (s.e.m.)% respectively compared with the initial response to GRF at 5 mmol/l in each column. The mean GH response to GRF from anterior pituitary cells of normal rats was 6·58 ± 0·88 μg/three pituitaries, which was not statistically different from that of cells from rats with streptozotocin-induced diabetes (5·40 ± 0·68 μg/three pituitaries). It is concluded that GH suppression in diabetic rats and during hypoglycaemia is not mediated by changes in the GH response to GRF. Journal of Endocrinology (1989) 122, 657–660

A procedure for the purification of somatotrophs isolated from rat anterior pituitary glands using Percoll density gradients

1982 ◽  
Vol 94 (2) ◽  
pp. 257-NP ◽  
Author(s):  
Marianne Hall ◽  
S. L. Howell ◽  
D. Schulster ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Cell Types ◽  
Male Rats ◽  
Prostaglandin E ◽  
Density Gradients ◽  
Pituitary Glands ◽  
Cyclic Amp Derivatives

We have used fractionation on density gradients of Percoll to separate the cell types in the rat anterior pituitary gland and to produce a purified preparation of somatotrophs. The method differs from those described previously which used, for example, albumin or Ficoll gradients, in being more rapid and avoiding low temperatures, and therefore gives cells with improved viability. Anterior pituitary glands from male rats were dispersed with trypsin to produce 1·5 × 106–2·0 × 106 cells/gland. These were fractionated on hyperbolic density gradients of Percoll. Two bands of cells containing somatotrophs were detected, one of which (band A; density 1·075–1·082 g/cm3) contained approximately 90% somatotrophs, whereas the other (band B; density 1·055–1·068 g/cm3) contained about 70% somatotrophs mixed with other cells, especially lactotrophs. Cells in band A appeared more responsive to secretagogues than those in band B; growth hormone secretion was stimulated markedly by cyclic AMP derivatives and prostaglandin E2, and inhibited by somatostatin. Such purified somatotrophs are well suited to biochemical studies on the mechanism of the control of growth hormone secretion.

ACETYLCHOLINE STIMULATES GROWTH HORMONE SECRETION, PHOSPHATIDYL INOSITOL LABELLING, 45Ca2+ EFFLUX AND CYCLIC GMP ACCUMULATION IN BOVINE ANTERIOR PITUITARY GLANDS

1979 ◽  
Vol 80 (2) ◽  
pp. 203-213 ◽  
Author(s):  
P. W. YOUNG ◽  
R. J. BICKNELL ◽  
J. G. SCHOFIELD
Keyword(s):  
Growth Hormone ◽  
Cyclic Gmp ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Phosphatidyl Inositol ◽  
Maximal Response ◽  
Tissue Responses ◽  
Pituitary Glands ◽  
Esterase Inhibitor

Acetylcholine (25 μmol/l) in the presence of the choline esterase inhibitor physostigmine (67 μmol/l) increased the release of growth hormone and efflux of 45Ca2+ from perifused bovine pituitary slices; the time taken for the maximal response to occur was the same. In batch incubations, acetylcholine (1 μmol/l–1 mmol/l) increased pituitary cyclic GMP concentrations in the pituitary gland within 2 min, and increased incorporation of [3H]inositol and [32P]phosphate into pituitary phosphatidyl inositol within 15 min. Cyclic AMP concentrations were not significantly changed 2 or 5 min after acetylcholine addition. All the tissue responses were inhibited by prior exposure of the tissue to atropine (1 μmol/l) but not by tubocurarine (10 μmol/l–1 mmol/l), indicating that the responses were mediated by receptors of the muscarinic type. The similarities between these responses and those to known hypothalamic hypophysiotrophic hormones are discussed.

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