Effect of intermittent infusions of somatostatin on growth hormone secretion in unrestrained male rats with hypothalamic deafferentation

SUMMARY A single 12 mg dose of stilboestrol dipropionate given to 100-day-old male rats resulted in increased pituitary mitotic activity, pituitary weight and serum growth hormone; the latter rose from a mean value of 20 ng/ml to a maximum of 342 ng/ml 9 days later. Serum growth hormone and pituitary mitotic activity then gradually diminished but were still slightly increased on day 28. Serum growth hormone and pituitary weight were significantly correlated during the periods of rapidly rising and of sustained high levels of serum growth hormone. Indices of mitotic activity were correlated with serum growth hormone during the periods of rapidly rising and of falling levels of serum growth hormone.

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Neuroanatomic localization of the inhibitory effect of TRH on growth hormone secretion

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1987.253.4.e354 ◽

1987 ◽

Vol 253 (4) ◽

pp. E354-E359

Author(s):

K. Ishikawa ◽

H. Katakami ◽

L. A. Frohman

Keyword(s):

Growth Hormone ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Inhibitory Effect ◽

Releasing Hormone ◽

Hypothalamic Deafferentation ◽

Electrolytic Lesions ◽

Plasma Gh ◽

The Right ◽

Lateral Cerebral Ventricle

The inhibitory effect of centrally administered thyrotropin-releasing hormone (TRH) on the plasma growth hormone (GH) response to GH-releasing hormone (GHRH) in the rat was studied in relation to the anatomic loci involved. Experiments were performed in animals with bilateral electrolytic lesions in the medial preoptic (MPO) area or with anterolateral hypothalamic deafferentation and in sham-operated controls. Blood samples were obtained every 10 to 20 min from and drugs were injected into freely moving animals with indwelling cannulas in the right atrium and lateral cerebral ventricle. In control animals, the plasma GH response to GHRH, 1 microgram iv, was almost completely inhibited by TRH, 1 microgram icv, injected 5 min previously. In animals with either MPO lesions or anterolateral hypothalamic deafferentation in which median eminence somatostatin immunochemical staining was almost completely eliminated, the GH response to GHRH was enhanced and TRH did not exhibit any inhibitory effect. These results, together with the previous observation that the inhibitory effect of TRH is blocked by prior treatment with anti-somatostatin serum, suggest that the effect of TRH is mediated by stimulation of somatostatin-containing neurons in the periventricular nucleus of the MPO area.

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Positive role of non-N-methyl-D-aspartate receptors in the control of growth hormone secretion in male rats

Journal of Endocrinological Investigation ◽

10.1007/bf03344969 ◽

1996 ◽

Vol 19 (6) ◽

pp. 353-358 ◽

Cited By ~ 4

Author(s):

L. Pinilla ◽

M. Tena-Sempere ◽

D. Gonzalez ◽

E. Aguilar

Keyword(s):

Growth Hormone ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Male Rats ◽

Positive Role

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Adrenergic and Dopaminergic Control of Growth Hormone Secretion in Urethane Anesthetized Adult Male Rats

Hormone Research ◽

10.1159/000178915 ◽

1978 ◽

Vol 9 (4) ◽

pp. 208-224 ◽

Cited By ~ 1

Author(s):

W. Ruch ◽

P. Marbach ◽

A.L. Jaton ◽

B. Bucher ◽

W. Doepfner

Keyword(s):

Growth Hormone ◽

Adult Male ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Male Rats ◽

Dopaminergic Control

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Interpulse growth hormone secretion in the episodic plasma profile causes the sex reversal of cytochrome P450s in senescent male rats

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2434273100 ◽

2003 ◽

Vol 100 (25) ◽

pp. 15224-15228 ◽

Cited By ~ 36

Author(s):

R. N. Dhir ◽

B. H. Shapiro

Keyword(s):

Growth Hormone ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Sex Reversal ◽

Cytochrome P450s ◽

Male Rats ◽

Plasma Profile

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DNA SYNTHESIS AND DEPLETION OF PROLACTIN IN THE PITUITARY GLAND OF THE MALE RAT

Journal of Endocrinology ◽

10.1677/joe.0.0770129 ◽

1978 ◽

Vol 77 (1) ◽

pp. 129-136 ◽

Cited By ~ 16

Author(s):

H. M. LLOYD ◽

J. M. JACOBI ◽

J. D. MEARES

Keyword(s):

Growth Hormone ◽

Dna Synthesis ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Prolactin Secretion ◽

Male Rats ◽

Male Rat ◽

Serum Prolactin ◽

Inhibitory Effects ◽

Pituitary Prolactin

Haloperidol, bromocriptine and diethylstilboestrol dipropionate were given in various régimes to male rats to determine their effects on pituitary DNA synthesis, prolactin secretion and growth hormone secretion. Haloperidol increased serum prolactin but did not stimulate pituitary DNA synthesis or reduce pituitary prolactin concentrations. Haloperidol potentiated the effects of oestrogen on serum prolactin and on pituitary DNA synthesis; pituitary prolactin concentrations were greatly reduced, and growth hormone secretion was slightly inhibited. The inhibitory effects of bromocriptine in oestrogen-stimulated rats were demonstrated by smaller pituitary weights and decreased DNA synthesis; serum prolactin levels were lowered and pituitary prolactin concentrations were increased. Haloperidol, given to rats treated with oestrogen and bromocriptine, reversed the inhibitory effects of bromocriptine on DNA synthesis and serum prolactin; pituitary prolactin concentrations fell to well below normal. The results suggest that the haloperidol potentiation of oestrogeninduced pituitary DNA synthesis may depend upon stimulation of prolactin secretion together with reduction of intracellular prolactin levels.

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