ESTIMATION OF PROLACTIN AND GROWTH HORMONE LEVELS BY POLYACRYLAMIDE DISC ELECTROPHORESIS

1969 ◽  
Vol 45 (2) ◽  
pp. 183-NP ◽  
Author(s):  
C. S. NICOLL ◽  
J. A. PARSONS ◽  
R. P. FIORINDO ◽  
C. W. NICHOLS
Keyword(s):  
Growth Hormone ◽  
Adult Male ◽  
Prolactin Secretion ◽  
Disc Electrophoresis ◽  
Male Rat ◽  
Rat Pituitary ◽  
Hypothalamic Tissue ◽  
Prolactin Content ◽  
High Degree

SUMMARY A procedure for estimating rat prolactin and growth hormone (somatotrophin, STH), by measuring the optical density of the electrophoretically isolated and stained hormone bands in polyacrylamide gel columns, is described and evaluated. A simple and inexpensive densitometer is also described. Prolactin levels in adenohypophyses and in medium from pituitary incubates were measured by electrophoresis-densitometry (ED) and by the pigeon crop-sac assay. The two methods showed a high degree of correlation. The validity of the ED method for estimating prolactin levels in adenohypophysial tissue and in incubation medium was demonstrated by comparing the prolactin content of adult male and female and of oestrogen-treated male glands and by experiments in vitro. The female pituitary contained about three times more prolactin than the male and the glands of oestrogen-treated males had levels about the same as those of females. It was also shown that the ED method could be used to demonstrate the inhibitory effects of extract of rat hypothalamic tissue on prolactin secretion in vitro by the rat pituitary. Levels of STH in adult male glands, as measured by this method, were comparable to results obtained by others using immunoassays. Propylthiouracil-induced hypothyroidism depressed the STH and prolactin levels in male rat pituitaries, in agreement with the observations of others. The stainability of the prolactin band in rat adenohypophyses was observed to decrease with time when the glands were stored on dry ice. No such change occurred in the staining characteristics of the STH band. Other aspects of the ED method are discussed, including its precision, efficiency, sensitivity, economy and utility.

2-HYDROXYOESTRADIOL INHIBITS PROLACTIN RELEASE FROM THE SUPERFUSED RAT PITUITARY GLAND

1981 ◽  
Vol 90 (3) ◽  
pp. 315-322 ◽  
Author(s):  
ELIZABETH A. LINTON ◽  
NICKI WHITE ◽  
OFELIA LIRA DE TINEO ◽  
S. L. JEFFCOATE
Keyword(s):  
Pituitary Gland ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Prolactin Release ◽  
Rat Pituitary ◽  
Lh Release

The effects of 2-hydroxyoestradiol (2OH-OE2), dopamine, oestradiol-17β and 2OH-OE2 plus dopamine on prolactin and LH release from the male rat pituitary gland were examined in vitro. 2-Hydroxyoestradiol reduced prolactin secretion by 51% at 10−10 mol/l and by 34% at 10−7 mol/l, while oestradiol-17β had no effect at these doses. Dopamine alone (5 × 10−7 mol/l) decreased prolactin released by 58%, 2OH-OE2 plus dopamine produced a similar inhibition of 60%. No significant effect on LH release was observed throughout.

ONSET OF OESTROGEN-INDUCED PROLACTIN SECRETION AND DNA SYNTHESIS BY THE RAT PITUITARY GLAND

1977 ◽  
Vol 72 (1) ◽  
pp. 35-39 ◽  
Author(s):  
JOAN JACOBI ◽  
H. M. LLOYD ◽  
J. D. MEARES
Keyword(s):  
Dna Synthesis ◽  
Pituitary Gland ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Serum Prolactin ◽  
Rat Pituitary ◽  
The Times ◽  
Pituitary Prolactin

SUMMARY The times of onset of oestrogen-induced prolactin secretion and DNA synthesis were studied in the pituitary gland of the male rat. At intervals from 3 to 96 h after injection of 10 mg diethylstilboestrol dipropionate, serum and pituitary prolactin concentrations were measured by radioimmunoassay and pituitary DNA synthesis by incorporation of [3H]thymidine in vitro. Serum prolactin was raised significantly from 6 h onwards and DNA synthesis was increased from 30 h onwards. Pituitary prolactin concentration began to increase at 30 h. Significant correlations were obtained between serum prolactin and DNA synthesis from 24 to 72 h but not during the period of prolactin secretion from 6 to 24 h.

Autoregulation of rat pituitary prolactin secretion demonstrated by a new perfusion method

1982 ◽  
Vol 242 (4) ◽  
pp. E226-E233
Author(s):  
H. A. Zacur ◽  
W. E. Mitch ◽  
J. E. Tyson ◽  
P. T. Ostrow ◽  
G. V. Foster
Keyword(s):  
Prolactin Secretion ◽  
Renal Capsule ◽  
In Vitro Perfusion ◽  
Prolactin Release ◽  
Rat Pituitary ◽  
Inbred Rats ◽  
Pituitary Glands ◽  
Prolactin Content ◽  
Pituitary Prolactin

Regulation of prolactin secretion was investigated by perfusing rat pituitaries in vitro. Two pituitary glands from inbred rats were transplanted beneath the renal capsule of a third recipient rat. Three weeks later, the transplanted kidney was removed and perfused in vitro with a defined cell-free medium. Normal renal function was maintained during perfusion, and cell morphology of the transplants remained unchanged as assessed by electron microscopy. Pituitary prolactin content did not change after 120 min of perfusion despite release of approximately 10 micrograms of hormone. Thyrotropin-releasing hormone (10 ng/ml) did not stimulate prolactin release; dopamine (20 ng/ml) rapidly, but transiently inhibited prolactin release; bromocriptine (20 ng/ml) rapidly and persistently inhibited prolactin release; haloperidol (100 ng/ml) blocked the inhibition by dopamine or bromocriptine, but when given alone inhibited prolactin release. Finally, prolactin release was also inhibited by the presence of 100 and 200 ng/ml, but not 50 ng/ml of NIAMDD RP-1 rat prolactin. It is concluded that in vitro perfusion of transplanted rat pituitaries provides a new model for studying the direct effect of agents on the secretion of prolactin from the pituitary and that rat prolactin and/or its metabolites directly inhibit pituitary prolactin secretion.

Modulation of prolactin secretion by contraceptive progestins in cultured rat pituitary cells in vitro

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S188-S189
Author(s):  
L. KIESEL ◽  
T. RABE ◽  
D. SCHOLZ ◽  
V. KIRSCHNER ◽  
B. RUNNEBAUM
Keyword(s):  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

In vitro metabolism of 3H-androstenedione by the male rat pituitary, hypothalamus, and hippocampus

Steroids ◽  
1975 ◽  
Vol 25 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Ana E. Pérez ◽  
Alfredo Ortíz ◽  
Marisa Cabeza ◽  
Carlos Beyer ◽  
Gregorio Pérez-Palacios
Keyword(s):  
In Vitro Metabolism ◽  
Male Rat ◽  
Rat Pituitary

A COMPARISON OF THE EFFECTS OF FOUR ERGOT DERIVATIVES ON PROLACTIN SECRETION BY DISPERSED RAT PITUITARY CELLS

1980 ◽  
Vol 87 (1) ◽  
pp. 95-103 ◽  
Author(s):  
G. DELITALA ◽  
T. YEO ◽  
ASHLEY GROSSMAN ◽  
N. R. HATHWAY ◽  
G. M. BESSER
Keyword(s):  
Anterior Pituitary ◽  
Ergot Alkaloids ◽  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Inhibitory Effects ◽  
Prolactin Release ◽  
Ergot Derivatives ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

The inhibitory effects of dopamine and various ergot alkaloids on prolactin secretion were studied using continuously perfused columns of dispersed rat anterior pituitary cells. Bromocriptine (5 nmol/l) and lisuride hydrogen maleate (5 nmol/l) both inhibited prolactin secretion, the effects persisting for more than 3 h after the end of the administration of the drugs. A similar although less long-lasting effect was observed with lergotrile (50 nmol/l) and the new ergoline derivative, pergolide (5 nmol/l). These effects contrasted with the rapid disappearance of the action of dopamine. The potency estimates of the ergots relative to that of dopamine were: lergotrile, 2·3; bromocriptine, 13; lisuride, 15; pergolide, 23. The dopamine-receptor blocking drugs, metoclopramide and haloperidol, antagonized the prolactin release-inhibiting activity of the compounds; bromocriptine and lisuride showed the highest resistance to this dopaminergic blockade. The results suggested that the direct effect of the ergot derivatives on dispersed pituitary cells was mediated through dopamine receptors and emphasized the long-lasting action of bromocriptine and lisuride in vitro.

Production and utilization of monoclonal antibodies to human/rat corticotrophin-releasing factor-41

1990 ◽  
Vol 5 (2) ◽  
pp. 159-166 ◽  
Author(s):  
N. G. N. Milton ◽  
E. W. Hillhouse ◽  
S. A. Nicholson ◽  
C. H. Self ◽  
A. M. McGregor
Keyword(s):  
Monoclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Corticotrophin Releasing Factor ◽  
Tissue Extracts ◽  
Rat Pituitary ◽  
Hypothalamic Tissue ◽  
Dose Dependent

ABSTRACT Murine monoclonal antibodies against human/rat corticotrophin-releasing factor-41 (CRF-41) were produced and characterized for use in the immunological and biological characterization of CRF-41. Spleen cells from BALB/c mice immunized with CRF-41 conjugated to bovine γ-globulin were fused with a BALB/c-derived non-secretor X-63 myeloma line. Hybridomas were selected for CRF antibody production by enzyme-linked immunosorbent assay, and positive hybridomas cloned twice. Three monoclonal antibodies were obtained (KCHMB001, KCHMB002 and KCHMB003) and characterized as IgG1, IgG1 and IgG2a isotypes respectively, with affinity constants for rat CRF-41 of 30, 53 and 34 nmol/l respectively. All three monoclonal antibodies recognize an epitope contained between residues 34 and 41 of the human/rat sequence. The antibodies were able to neutralize the ACTH-releasing activity of rat CRF-41, applied to rat pituitary fragments in vitro, in a dose-dependent manner. Isoelectric focusing showed that KCHMB 003 detected bands of synthetic rat CRF-41 and rat [Met(O)21,38]-CRF-41 at pH 7·1 and 6·8 respectively. Use of KCHMB003 in a two-site enzyme-amplified immunoassay showed that this antibody recognizes both synthetic rat CRF-41 and immunoreactive CRF-41 in rat hypothalamic tissue extracts.

Periodic interactions of GH-releasing factor and somatostatin can augment GH release in vitro

1987 ◽  
Vol 253 (5) ◽  
pp. E508-E514
Author(s):  
J. Weiss ◽  
M. J. Cronin ◽  
M. O. Thorner
Keyword(s):  
Growth Hormone ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Male Rat ◽  
Base Line ◽  
Additive Effects ◽  
Growth Hormone Releasing Factor ◽  
The Impact

Growth hormone (GH) is secreted as pulses in vivo. To understand the signals governing this periodicity, we have established a perifusion-based model of pulsatile GH release. Male rat anterior pituitaries were dispersed and perifused with pulses of human growth hormone-releasing factor-(1--40) (GHRF), with or without a continuous or discontinuous somatostatin tonus. An experiment was composed of a 1-h base-line collection followed by four 3-h cycles; each contained single or paired 10-min infusion(s) of 3 nM GHRF. In testing the impact of somatostatin, the protocol was identical except that 0.3 nM somatostatin was added 30 min into the base-line period and then was either continued throughout the study or withdrawn during the periods of GHRF infusion. GH base lines with somatostatin were lower than vehicle base lines (P less than 0.05). GHRF pulses generated consistent peaks of GH release between 200 and 300 ng. min-1. (10(7) cells)-1, and these peaks were not altered by continuous somatostatin. In contrast, withdrawal of somatostatin during GHRF administration elicited markedly higher GH peaks (P less than 0.05) and more total GH release (P less than 0.05). This response could not be accounted for by the additive effects of GHRF and somatostatin withdrawal.

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