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.

scholarly journals Evidence that the stimulation of lipogenesis in the mammary glands of starved lactating rats re-fed with a chow diet is dependent on continued hepatic gluconeogenesis during the absorptive period. Effects of a gluconeogenic inhibitory, mercaptopicolinic acid, in vivo

1985 ◽  
Vol 228 (3) ◽  
pp. 727-733 ◽  
Author(s):  
D H Williamson ◽  
V Ilic ◽  
R G Jones
Keyword(s):  
Mammary Gland ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Mammary Glands ◽  
Hepatic Glycogen ◽  
Chow Diet ◽  
Hepatic Gluconeogenesis ◽  
Rapid Stimulation ◽  
Stimulation Of

The rapid stimulation of lipogenesis in mammary gland that occurs on re-feeding starved lactating rats with a chow diet was decreased (60%) by injection of mercaptopicolinic acid, an inhibitor of hepatic gluconeogenesis at the phosphoenolpyruvate carboxykinase step. Mercaptopicolinate had no effect on lipogenesis in mammary glands of fed lactating rats. The inhibition of lipogenesis persisted in vitro when acini from mammary glands of re-fed rats treated with mercaptopicolinate were incubated with [1-14C]glucose. Mercaptopicolinate added in vitro had no significant effect on lipogenesis in acini from starved-re-fed lactating rats. Mercaptopicolinate prevented the deposition of glycogen and increased the rate of lipogenesis in livers of starved-re-fed lactating rats, whereas it had no significant effect on livers of fed lactating rats. Administration of intraperitoneal glucose restored the rate of mammary-gland lipogenesis in re-fed rats treated with mercaptopicolinate to the values for re-fed rats. Hepatic glycogen deposition was also restored, and the rate of hepatic lipogenesis was stimulated 5-fold. It is concluded that stimulation of mammary-gland lipogenesis on re-feeding with a chow diet after a period of starvation is in part dependent on continued hepatic gluconeogenesis during the absorptive period. Possible sources of the glucose precursors are discussed.

scholarly journals The dynamics of morphological changes during in vitro aging of bovine virgin mammary gland neutrophils

2012 ◽  
Vol 47 (No. 12) ◽  
pp. 325-332 ◽  
Author(s):  
Z. Sládek ◽  
D. Vašíčková ◽  
D. Ryšánek
Keyword(s):  
Mammary Gland ◽  
Trypan Blue ◽  
Morphological Changes ◽  
Membrane Integrity ◽  
Mammary Glands ◽  
Progressive Increase ◽  
Apoptotic Bodies ◽  
Bovine Mammary Gland ◽  
Cell Counts

The present study was an in vitro analysis of the dynamics of bovine mammary gland neutrophil apop­tosis based on the detection of morphological changes. The neutrophils were isolated from mammary glands of five virgin heifers. The mammary glands were lavaged, the suspensions were then bacteriologically examined, and total and differential cell counts were made. The cells were cultivated in vitro for 4 hours. After 2, 3 and 4 hours of cultivation, they were panoptically stained, and the proportions of apoptotic neutrophils and trypan blue positive neutrophils were determined. Neutrophil apoptosis and impaired cytoplasmic membrane integrity of neutrophils were already observed in the mammary gland lavages (11.9% and 0.8%, respectively). During the cultivation, a progressive increase in the number of apoptotic neutrophils in various stages of apoptosis – karyopyknosis, zeiosis and apoptotic bodies – was observed. Karyopyknotic neutrophils represented a dominant part of the apoptotic neutrophil population in the course of the whole cultivation. The most intensive increase was observed in zeiosis, whereas the levels of apoptotic bodies remained the same. After 4 hours of cultivation, 31.7% apoptotic neutrophils and 9.8% trypan blue positive neutrophils (i.e. Secondary necrotic cells) were found. The results of this work show that spontaneous apoptosis and secondary neutrophil necrosis must be taken into account during in vitro cultivations of bovine mammary gland neutrophils.

scholarly journals The protein-synthesizing activity of ribosomes isolated from the mammary gland of lactating and pregnant guinea pigs

1971 ◽  
Vol 123 (5) ◽  
pp. 865-874 ◽  
Author(s):  
E. Fairhurst ◽  
Diana McIlreavy ◽  
P. N. Campbell
Keyword(s):  
Protein Synthesis ◽  
Mammary Gland ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Cyanogen Bromide ◽  
Mammary Glands

1. Polyribosome preparations were made from the deoxycholate-treated post-nuclear fractions obtained by the disruption of mammary glands from lactating and pregnant guinea pigs. 2. A high proportion of large polyribosomes was obtained from the glands of lactating animals whereas mainly small polyribosomes were obtained from the glands of pregnant animals. The isolated preparations incorporated [14C]phenylalanine into protein. The polyribosomes from the glands of pregnant animals were less active than those from the glands of lactating animals but the activity of the former was stimulated more by poly(U) than was the latter. 3. The ribosomes from mammary gland could be dissociated into subunits after incubation, under conditions necessary for protein synthesis, in the presence of puromycin. The subunits could be recombined to give a preparation that actively polymerized [14C]phenylalanine in the presence of poly(U). The subunits from guinea-pig mammary gland could be combined with subunits from liver of either guinea pig or rat. Hybrid ribosomes were also formed from subunits derived from glands of pregnant and lactating animals. The hybrids were as active as were the ribosomes formed by reassociation of subunits from the same tissue, suggesting that in this respect the ribosomes from pregnant animals were not defective. 4. Polyribosomes from mammary glands of lactating animals when incubated with cell sap from the same source were tested for their ability to synthesize α-lactalbumin. The polyribosomes were incubated in the presence of [3H]leucine and α-lactalbumin was isolated from the supernatant. The protein was finally treated with cyanogen bromide and the C-terminal and N-terminal fragments were separated and their radioactivity was determined. Both fragments were radioactive consistent with the synthesis of α-lactalbumin. 5. The results are discussed in relation to protein synthesis in the mammary gland after parturition.

scholarly journals Characterization and biological activity of relaxin in porcine milk

Reproduction ◽  
2011 ◽  
Vol 141 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Amy-Lynn Frankshun ◽  
Teh-Yuan Ho ◽  
David C Reimer ◽  
Joseph Chen ◽  
Salamia Lasano ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Milk Proteins ◽  
Immunoblot Analysis ◽  
Mammary Tissue ◽  
Early Lactation ◽  
Maternal Circulation ◽  
A Site ◽  
Porcine Milk ◽  
Primary Form

A lactocrine mechanism for delivery of maternally derived relaxin (RLX) into the neonatal circulation as a consequence of nursing was proposed for the pig. Immunoreactive RLX was detected in colostrum and in the serum of newborn pigs only if they were allowed to nurse. Milk-borne RLX concentrations are highest during early lactation (9–19 ng/ml), declining to <2 ng/ml by postnatal day 14. Whether milk-borne RLX is bioactive is unknown. Evidence that RLX concentrations in milk are higher than in maternal circulation in several species suggests the mammary gland as a site of local RLX production. It is unknown whether the porcine mammary gland is a source of RLX. Therefore, objectives were to evaluate RLX bioactivity in porcine milk during the first 2 weeks of lactation, identify the form of RLX in porcine milk, and determine whether mammary tissue from early lactation is a source of milk-borne RLX. Milk RLX bioactivity was determined using anin vitrobioassay in which cAMP production by human embryonic kidney (HEK293T) cells transfected with the human RLX receptor (RXFP1) was measured. RLX bioactivity was highest at lactation day (LD) 0, decreasing to undetectable levels by LD 4. Immunoblot analysis of milk proteins revealed an 18 kDa band, indicating proRLX as the primary form of RLX in porcine milk. ProRLX protein and transcripts were detected in porcine mammary tissue on LD 0 and 7. Results support the lactocrine hypothesis by defining the nature and a potential source for bioactive proRLX in porcine colostrum/milk.

The endocrine system and vomiting in pregnant women

1926 ◽  
Vol 22 (11) ◽  
pp. 1296-1296
Keyword(s):  
Mammary Gland ◽  
Pituitary Gland ◽  
Pregnant Women ◽  
Corpus Luteum ◽  
Carbohydrate Metabolism ◽  
Endocrine System ◽  
Posterior Pituitary ◽  
Posterior Pituitary Lobe

The author notes in hyperemesis a disorder of carbohydrate metabolism and depletion of the liver in glycogen, which, in his opinion, is due to increased secretion of the posterior pituitary lobe. Normally, this secretion is regulated by hormones of the mammary gland, placenta, and corpus luteum. If these hormones are insufficient, hyperfunction of the pituitary gland with its consequences occurs.

BREAKDOWN OF [3H]OXYTOCIN BY RAT TISSUES IN VITRO

1973 ◽  
Vol 59 (2) ◽  
pp. 305-312
Author(s):  
SANDRA M. EGAN ◽  
A. LIVINGSTON
Keyword(s):  
Skeletal Muscle ◽  
Mammary Gland ◽  
Incubation Medium ◽  
Rat Tissues ◽  
Tissue Uptake ◽  
Tissue Extracts ◽  
Rat Mammary Gland

SUMMARY Tissue uptake of oxytocin by rat mammary gland, uterus, heart and skeletal muscle was demonstrated by incubation of these tissues with 3H-labelled oxytocin. Chromatography of tissue extracts showed that some breakdown of oxytocin had occurred after only 30 s. However, in all cases there was no breakdown of oxytocin in the corresponding incubation medium. This indicated that the breakdown of oxytocin occurred within the tissues.

HUMAN PROLACTIN. EVIDENCE OBTAINED BY THE BIOASSAY OF HUMAN PLASMA

1971 ◽  
Vol 51 (1) ◽  
pp. 157-NP ◽  
Author(s):  
ISABEL A. FORSYTH ◽  
RITA P. MYRES
Keyword(s):  
Active Material ◽  
Gel Filtration ◽  
Human Growth ◽  
Culture Method ◽  
Early Lactation ◽  
Posterior Pituitary ◽  
Human Prolactin ◽  
Single Plasma ◽  
Plasma Assay

SUMMARY Single plasma samples from 27 control subjects and from 18 women in early lactation have been assayed for lactogenic activity using a semi-quantitative rabbit mammary gland organ culture method. Tests with a variety of anterior pituitary, posterior pituitary, placental and steroid hormones have shown the method to be specific for prolactin and for prolactin-like hormones such as human growth hormone (HGH) and human chorionic somatomammotrophin (HCS). Twelve of the 18 samples from women in early lactation gave positive lactogenic responses, while only one of the control samples did so. Plasma HGH levels were measured by radioimmunoassay. The levels of HGH in the medium, resulting from addition of plasma, were in all cases below the limits of sensitivity of the assay. The conclusion that human prolactin immunologically distinct from HGH is being measured is supported by the failure of antiserum to HGH to affect the in-vitro lactogenic response to plasma. Assay of fractions prepared from plasma by gel filtration suggests a molecular weight of approximately 20000 for the lactogenically active material.

667. Synthesis of lactose in vitro by mammary gland slices from lactating rats, guinea-pigs and sheep

1957 ◽  
Vol 24 (2) ◽  
pp. 171-173 ◽  
Author(s):  
W. G. Duncombe
Keyword(s):  
Mammary Gland ◽  
Guinea Pigs ◽  
Species Differences

There can now be little doubt that glucose is the principal precursor of lactose in the mammary gland. Evidence for this comes form in vivo and in vitro studies, using both analytical and isotopic techniques (1), though considerable species differences have been noted.

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