THE EFFECTS OF HIGHLY PURIFIED POSTERIOR PITUITARY PRINCIPLES ON THE LACTATING MAMMARY GLAND OF THE RABBIT

1953 ◽  
Vol 9 (2) ◽  
pp. 232-235 ◽  
Author(s):  
B. A. CROSS ◽  
H. B. VAN DYKE
Keyword(s):  
Mammary Gland ◽  
Posterior Pituitary ◽  
Milk Ejection ◽  
Rat Uterus ◽  
Lactating Mammary Gland

1. The milk-ejection activity of highly purified oxytocic and vasopressor-antidiuretic (ADH) polypeptides was determined on the intact mammary gland of the lactating rabbit. 2. When assayed in this way, 100 units of vasopressin-ADH had an activity represented by 17 units of oxytocin. 3. The lactating rabbit mammary gland is more sensitive to oxytocin than the rat uterus, and appears to be the best means at present available for assessing milk-ejection activity.

EFFECT OF LOCALLY IMPLANTED OESTROGEN ON THE RESPONSE OF THE RAT'S LACTATING MAMMARY GLAND TO OXYTOCIN

1973 ◽  
Vol 73 (4) ◽  
pp. 700-712 ◽  
Author(s):  
J. D. Bruce ◽  
X. Cofre ◽  
V. D. Ramirez
Keyword(s):  
Mammary Gland ◽  
Mammary Glands ◽  
Myoepithelial Cells ◽  
Recording System ◽  
Saline Infusion ◽  
High Dose ◽  
Low Doses ◽  
Milk Ejection ◽  
Lactating Mammary Gland ◽  
Small Rise

ABSTRACT On the day following delivery (day 1 of lactation) one abdominal mammary gland was implanted with oestrogen and the contralateral gland received an empty needle. At 2, 5 or 10 days of lactation the rats were anaesthetized with pentobarbital and the nipples of both abdominal glands were cannulated and their pressures recorded by means of transducers coupled to an amplifier and recording system. The normal mammary glands of 5-day lactating rats responded to very low doses of oxytocin (Syntocinon®, Sandoz) (5× 10−8 mU) with a rhythmic elevation in pressure. However, saline infusion also evoked a small rise in intra-mammary pressure. Earlier (2 days) and later (10 days) in lactation the responses were smaller. Oestrogen decreases significantly the milk ejection response to oxytocin, and the effect was maximal at day 10 of lactation. Histological observations confirmed the diminished reaction of the gland to oxytocin, since the milk was retained in the alveoli of rats bearing a mammary-oestrogen implant. A paradoxical rise in pressure was detected in normal as well as in oestrogen-implanted glands when the lowest dose of oxytocin was injected in lactating rats which had previously received a high dose of oxytocin (50 mU or 500 mU). These results reinforce the hypothesis that oestrogen alters the milk ejection response to oxytocin and that the mechanism is probably related to changes in the contractility of the myoepithelial cells.

SUCKLING IN THE GUINEA-PIG: THE EFFECTS OF PASSIVE IMMUNIZATION WITH AN ANTISERUM TO OXYTOCIN

1981 ◽  
Vol 90 (2) ◽  
pp. 237-244 ◽  
Author(s):  
I. C. A. F. ROBINSON ◽  
J. A. PARSONS
Keyword(s):  
Mammary Gland ◽  
Passive Immunization ◽  
High Titre ◽  
Immune Serum ◽  
In Vitro Experiments ◽  
Posterior Pituitary ◽  
Milk Ejection ◽  
Posterior Pituitary Gland

Lactating guinea-pigs were passively immunized with an antiserum to oxytocin of high titre, specificity and avidity. Single i.v. injections of 0·1–0·4 ml antiserum produced high titres which decayed slowly (half-life ≃7 days). Passively administered antiserum was effective in vivo; the clearance of exogenous oxytocin from plasma was greatly slowed in immunized animals. Passive immunization with 0·4 ml antiserum reduced milk transfer to the litter during suckling episodes of 10 min, and overall litter growth rates were significantly decreased. Non-immune serum was without effect. Plasma neurophysin levels showed the same large rises during suckling in immunized animals, indicating that neurohypophysial activation was unimpaired. Despite the presence of high titres of antiserum, some milk transfer still occurred at milk ejection. In-vitro experiments showed that more than 25% of oxytocin remained free 20 s after mixing with plasma taken from passively immunized animals. It is probable that the antiserum in the circulation was unable to bind all the oxytocin released from the posterior pituitary gland before it reached the mammary gland.

STUDIES ON THE HORMONAL CONTROL OF THE MILK-EJECTION ACTIVITY IN LACTATING RABBITS

1963 ◽  
Vol 44 (2) ◽  
pp. 313-324 ◽  
Author(s):  
Stig Kullander
Keyword(s):  
Mammary Gland ◽  
Intravenous Administration ◽  
Intravenous Infusion ◽  
Clinical Findings ◽  
Hormonal Control ◽  
Milk Ejection ◽  
Lysine Vasopressin ◽  
Lactating Mammary Gland ◽  
Oxytocin Infusion ◽  
Synthetic Oxytocin

ABSTRACT A study was made of the effect of synthetic oxytocin (Syntocinon Sandoz) and synthetic lysine-vasopressin (Vasopressin Sandoz) on the milk-ejecting activity of the lactating mammary gland of the rabbit. Both drugs were given by intravenous infusion except in some cases where oxytocin was injected intravenously in single doses. Depending on the sensitivity of the mammary gland and the amount of oxytocin administered, infusion of this hormone gave a prolonged tonic increase in the milk pressure or a rhythmic series of pressure increases. Both these reactions could be counteracted appreciably by giving vasopressin simultaneously in doses of the order of 1:4 to 1:1 in relation to the dose of oxytocin. After withdrawal of vasopressin the original effect of the oxytocin in the milk-gland pressure was slowly resumed. Doses of vasopressin with ratios of 1:1000 – 1:5 or saline had little or no effect at all. Intravenous administration of adrenaline also caused transient suppression of the effect of the oxytocin infusion. There was no evidence to indicate that vasopressin potentiated this effect. These findings are discussed in relation to the clinical findings of disturbance in the milk let-down during different stress situations. Both vasopressin and adrenaline might be released during stress.

Antiestrogenic effects of the polyaromatic hydrocarbon 3-methylcholanthrene in the rat uterus and mammary gland

2015 ◽  
Vol 122 (03) ◽  
Author(s):  
G Kretzschmar ◽  
J Helle ◽  
A Keiler ◽  
O Zierau ◽  
G Vollmer
Keyword(s):  
Mammary Gland ◽  
Polyaromatic Hydrocarbon ◽  
Rat Uterus ◽  
Antiestrogenic Effects

ÜBER DIE WIRKUNG PHARMAKOLOGISCHER OXYTOCINDOSEN AUF DIE MILCHDRÜSE

1960 ◽  
Vol XXXIV (IV) ◽  
pp. 543-557 ◽  
Author(s):  
B. Berde ◽  
A. Cerletti
Keyword(s):  
Mammary Gland ◽  
Intravenous Administration ◽  
Intravenous Infusion ◽  
Intranasal Administration ◽  
Intramuscular Injection ◽  
Different Types ◽  
Lactating Mammary Gland ◽  
Synthetic Oxytocin

ABSTRACT A study was made of the influence of pharmacological amounts of synthetic oxytocin (»Syntocinon«) on the lactating mammary gland of the rabbit. The drug was given by intravenous infusion, by intramuscular injection and by intranasal administration. Two different types of reaction were noted: a tonic reaction, i. e. a lasting increase in pressure in the mammary gland without significant fluctuations, or a rhythmic reaction, i. e. a series of increases in pressure at more or less regular intervals. In order to elicit reactions approximately identical in intensity and character with those produced by intravenous infusion, it was necessary to give approximately 1.5 to 8.0 times as much by intramuscular injection and approximately 10 to 100 times as much by intranasal administration. Intravenous administration of adrenaline transiently suppressed a long-lasting reaction to oxytocin.

The calcium-sensing receptor regulates PTHrP production and calcium transport in the lactating mammary gland

Bone ◽  
2006 ◽  
Vol 38 (6) ◽  
pp. 787-793 ◽  
Author(s):  
Laleh Ardeshirpour ◽  
Pamela Dann ◽  
Martin Pollak ◽  
John Wysolmerski ◽  
Joshua VanHouten
Keyword(s):  
Mammary Gland ◽  
Calcium Transport ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing ◽  
Lactating Mammary Gland

THE MOTILITY AND REACTIVITY OF THE OESTROGENIZED RABBIT UTERUS IN VIVO; WITH COMPARATIVE OBSERVATIONS ON MILK EJECTION

1958 ◽  
Vol 16 (3) ◽  
pp. 237-260 ◽  
Author(s):  
B. A. CROSS
Keyword(s):  
Spinal Cord ◽  
Mammary Gland ◽  
Spinal Anaesthesia ◽  
Dose Range ◽  
Abdominal Muscles ◽  
Mechanical Stimuli ◽  
Milk Ejection ◽  
Thoracic Spinal ◽  
Spontaneous Motility ◽  
Stimulation Of

SUMMARY The spontaneous motility of the intact uterus of spayed oestrogenized rabbits under sodium pentobarbitone anaesthesia has been recorded. Both uteri of each animal behaved similarly, and contractions often appeared to be synchronous. Small changes of load affected the amplitude of contractions, but did not alter uterine responsiveness to neurohypophysial or adrenomedullary hormones. Mid-thoracic section of the spinal cord obliterated spontaneous motility of the uterus; spinal anaesthesia did not. Spontaneous motility persisted for as long as 7 hr after decerebration and removal of the pituitary gland. The threshold dose of oxytocin for activating the oestrogenized uterus was the same as that for the lactating mammary gland, i.e. 1–5 mu. Doses up to 50 mu. usually gave an increase in frequency and amplitude of contractions. In the same dose range vasopressin either had little effect or inhibited spontaneous uterine motility, although milk ejection was stimulated. Slow infusion of oxytocin at rates of 1·5–48 mu./min produced graded increases in the rate and depth of uterine contractions and, at the same time, in similarly treated, lactating animals, rhythmic milk-ejection responses which at the higher rates of infusion merged to give a tetanic (plateau) type of milk ejection. Adrenaline or noradrenaline in doses of 1–5 μg produced diphasic uterine responses, initial contractions being followed by inhibition of spontaneous motility. They also inhibited the uterine, as well as the milk-ejection response to oxytocin injected 10–30 sec later. The inhibitory effect of adrenaline on both organs was about twice that of noradrenaline. The above-mentioned responses to adrenaline and oxytocin could also be elicited by electrical stimulation of the hypothalamus. Stimuli in the dorsal, lateral, perifornical and posterior hypothalamic areas produced effects equivalent to those of 1–5 μg adrenaline on both the uterus and mammary gland. These responses were abolished by mid-thoracic section of the spinal cord or by spinal anaesthesia. In such preparations responses typical of those produced by oxytocin were seen in both organs after stimulation of the paraventricular nuclei, supraoptic nuclei and the hypothalamo-hypophysial nerve pathways of the tuber cinereum and neural stalk. Dilatation of the vagina (or rectum) gave rise to a uterine response similar to that resulting from adrenaline or noradrenaline. The response was abolished by spinal anaesthesia, but not by mid-thoracic spinal section or decerebration. The same stimuli also produced 'bearing down' contractions of the abdominal muscles. Contractions of the uterus could also be elicited by mechanical stimuli, in the absence of functional spinal connexions.

scholarly journals Peptide Transport and Metabolism by the Lactating Mammary Gland

2016 ◽  
Vol 146 (2) ◽  
pp. 384-384
Author(s):  
David B Shennan
Keyword(s):  
Mammary Gland ◽  
Peptide Transport ◽  
Lactating Mammary Gland

scholarly journals Evidence for conservation of dietary lipid in the rat during lactation and the immediate period after removal of the litter. Decreased oxidation of oral [1-14C]triolein

1986 ◽  
Vol 239 (1) ◽  
pp. 233-236 ◽  
Author(s):  
C M Oller do Nascimento ◽  
D H Williamson
Keyword(s):  
Adipose Tissue ◽  
Mammary Gland ◽  
Lipoprotein Lipase ◽  
Relative Activity ◽  
Dietary Lipid ◽  
Litter Removal ◽  
Lactating Mammary Gland ◽  
14Co2 Production

Production of 14CO2 from an oral load of [1-14C]triolein was greatly decreased (70%) in lactating rats or immediately after (24-48 h) removal of the litter, compared with virgin rats. This decreased oxidation of dietary lipid was accompanied by accumulation of 14C-labelled lipid in lactating mammary gland or adipose tissue (after litter removal). No difference in 14CO2 production between lactating and virgin rats was observed when [1-14C]octanoate was administered. It is concluded that a major factor in this conservation of dietary triacylglycerol is the relative activity of lipoprotein lipase in the tissues.

THE IN VITRO METABOLISM OF MAMMARY GLAND SLICES IN THE PRESENCE OF POSTERIOR PITUITARY LOBE EXTRACTS RICH IN MELANOPHORE-DISPERSING ACTIVITY

1957 ◽  
Vol 15 (4) ◽  
pp. 366-373 ◽  
Author(s):  
T. R. BRADLEY ◽  
G. M. MITCHELL
Keyword(s):  
Mammary Gland ◽  
Guinea Pigs ◽  
Incubation Medium ◽  
Mammary Glands ◽  
Gas Evolution ◽  
Early Lactation ◽  
Posterior Pituitary ◽  
Rats And Mice ◽  
Posterior Pituitary Lobe

SUMMARY Slices cut from mammary glands of rats and mice during gestation and lactation were incubated in vitro in the presence of pig posterior pituitary lobe extracts rich in melanophore-dispersing ('B') activity. Slices taken in early lactation but not during gestation or late lactation showed increased net gas evolution compared with control slices. Similar tissue from rabbits and guinea-pigs did not give rise to this effect, nor did slices of other tissues taken from lactating rats. The increased net gas evolution was not observed in the absence of glucose from the incubation medium. Treatment of the 'B' extract with NaOH or hypophysectomy of the rats prior to use decreased the response.

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