XXIV.—The Innervation of the Human Quiescent Nipple, with Notes on Pigmentation, Erection, and Hyperneury

1949 ◽  
Vol 61 (3) ◽  
pp. 699-717 ◽  
Author(s):  
E. P. Cathcart ◽  
F. W. Gairns ◽  
H. S. D. Garven

It has been known from antiquity that involution of the uterus is aided by putting the child to the breast, and the work of Moir (1933) has demonstrated conclusively that suckling brings about waves of contraction of the puerperal uterus. Since suckling must necessarily involve stimulation of the nipple, it seemed of interest to know what sensory apparatus is present in the nipple to receive these stimuli. While histological studies of the mammary gland itself have been numerous, only slight attention has been paid to the histological structure of the areola and the nipple.It must be appreciated from the outset that the present study is devoted to the innervation of the nipple in the quiescent breast. There may be considerable change during pregnancy and lactation, not only in the size of the organ and its epithelium but also in the other structures. It has been shown that there is an increase in the number of nerve-fibres in the actively secreting mammary tissue, and it is possible that there is an increase in the nerve-structures of the nipple also. The richness of the innervation in the quiescent nipple certainly makes a further study of these nerve-structures during pregnancy and lactation of great interest.

2005 ◽  
Vol 289 (4) ◽  
pp. E634-E642 ◽  
Author(s):  
Craig P. Hasilo ◽  
Christopher R. McCudden ◽  
J. Ryan J. Gillespie ◽  
Kathi A. James ◽  
Edward R. Hirvi ◽  
...  

In most mammalian tissues, the stanniocalcin-1 gene (STC-1) produces a 50-kDa polypeptide hormone known as STC50. Within the ovaries, however, the STC-1 gene generates three higher-molecular-mass variants known as big STC. Big STC is targeted locally to corpus luteal cells to block progesterone release. During pregnancy and lactation, however, ovarian big STC production increases markedly, and the hormone is released into the serum. During lactation, this increase in hormone production is dependent on a suckling stimulus, suggesting that ovarian big STC may have regulatory effects on the lactating mammary gland. In this report, we have addressed this possibility. Our results revealed that virgin mammary tissue contained large numbers of membrane- and mitochondrial-associated STC receptors. However, as pregnancy progressed into lactation, there was a decline in receptor densities on both organelles and a corresponding rise in nuclear receptor density, most of which were on milk-producing, alveolar cells. This was accompanied by nuclear sequestration of the ligand. Sequestered STC resolved as one ∼135-kDa band in the native state and therefore had the appearance of a big STC variant. However, chemical reduction collapsed this one band into six closely spaced, lower-molecular-mass species (28–41 kDa). Mammary gland STC production also underwent a dramatic shift during pregnancy and lactation. High levels of STC gene expression were observed in mammary tissue from virgin and pregnant rats. However, gene expression then fell to nearly undetectable levels during lactation, coinciding with the rise in nuclear targeting. These findings have thus shown that the mammary glands are indeed targeted by STC, even in the virgin state. They have further shown that there are marked changes in this targeting pathway during pregnancy and lactation, accompanied by a switch in ligand source (endogenous to exogenous). They also represent the first example of nuclear targeting by STC.


1993 ◽  
Vol 139 (1) ◽  
pp. 37-49 ◽  
Author(s):  
J. J. Smith ◽  
A. V. Capuco ◽  
I. H. Mather ◽  
B. K. Vonderhaar

ABSTRACT Developmental variation in the expression of the prolactin receptor in the ruminant mammary gland was investigated. Affinity chromatography revealed that bovine prolactin and human GH each bound to the same mammary gland proteins, yielding fractions enriched in binding activity and a protein of Mr 36 000, assumed to be a bovine prolactin receptor. Affinity cross-linking of 125I-labelled human GH to mammary microsomes confirmed that the Mr 36 000 protein was a bovine prolactin receptor. Binding assays of receptors in microsomes from the mammary tissue of cows and ewes at various stages of the lactational/reproductive cycle indicated developmental regulation of receptor concentration, but not receptor type, as no other bovine prolactin receptor type was detected by affinity cross-linking. These results suggest that differences in the response to prolactin in the mammary gland at various developmental stages in ruminants are not due to the expression of different forms of the prolactin receptor, and the lack of a prolactin effect on established lactation in ruminants is not due to the absence of the Mr 36 000 form of the prolactin receptor. Journal of Endocrinology (1993) 139, 37–49


1999 ◽  
Vol 112 (11) ◽  
pp. 1771-1783 ◽  
Author(s):  
A.D. Metcalfe ◽  
A. Gilmore ◽  
T. Klinowska ◽  
J. Oliver ◽  
A.J. Valentijn ◽  
...  

Epithelial cells within the mammary gland undergo developmental programmes of proliferation and apoptosis during the pregnancy cycle. After weaning, secretory epithelial cells are removed by apoptosis. To determine whether members of the Bcl-2 gene family could be involved in regulating this process, we have examined whether changes in their expression occur during this developmental apoptotic program in vivo. Bax and Bcl-x were evenly expressed throughout development. However, expression of Bak and Bad was increased during late pregnancy and lactation, and the proteins were present during the time of maximal apoptotic involution. Thereafter, their levels declined. In contrast, Bcl-w was expressed in pregnancy and lactation but was downregulated at the onset of apoptosis. Bcl-2 was not detected in lactating or early involuting mammary gland. Thus, the pro-apoptotic proteins Bax, Bak and Bad, as well as the death-suppressors Bcl-x, Bcl-2 and Bcl-w, are synthesised in mouse mammary gland, and dynamic changes in the expression profiles of these proteins occurs during development. To determine if changes in Bak and Bcl-w expression could regulate mammary apoptosis, their effect on cultured mouse mammary epithelial cells was examined in transient transfection assays. Enforced expression of Bak induced rapid mammary apoptosis, which could be suppressed by coexpression of Bcl-w. In extracts of mammary tissue in vivo, Bak heterodimerized with Bcl-x whereas Bax associated with Bcl-w, but Bak/Bcl-w heterodimers were not detected. Thus, Bak and Bcl-w may regulate cell death through independent pathways. These results support a model in which mammary epithelial cells are primed for apoptosis during the transition from pregnancy to lactation by de novo expression of the death effectors Bak and Bad. It is suggested that these proteins are prevented from triggering apoptosis by anti-apoptotic Bcl-2 family proteins until involution, when the levels of Bcl-w decline. Our study provides evidence that regulated changes in the expression of cell death genes may contribute to the developmental control of mammary apoptosis.


Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 439-449 ◽  
Author(s):  
R.S. Talhouk ◽  
J.R. Chin ◽  
E.N. Unemori ◽  
Z. Werb ◽  
M.J. Bissell

The extracellular matrix (ECM) is an important regulator of mammary epithelial cell function both in vivo and in culture. Substantial remodeling of ECM accompanies the structural changes in the mammary gland during gestation, lactation and involution. However, little is known about the nature of the enzymes and the processes involved. We have characterized and studied the regulation of cell-associated and secreted mammary gland proteinases active at neutral pH that may be involved in degradation of the ECM during the different stages of mammary development. Mammary tissue extracts from virgin and pregnant CD-1 mice resolved by zymography contained three major proteinases of 60K (K = 10(3) Mr), 68K and 70K that degraded denatured collagen. These three gelatinases were completely inhibited by the tissue inhibitor of metalloproteinases. Proteolytic activity was lowest during lactation especially for the 60K gelatinase which was shown to be the activated form of the 68K gelatinase. The activated 60K form decreased prior to parturition but increased markedly after the first two days of involution. An additional gelatin-degrading proteinase of 130K was expressed during the first three days of involution and differed from the other gelatinases by its lack of inhibition by the tissue inhibitor of metalloproteinases. The activity of the casein-degrading proteinases was lowest during lactation. Three caseinolytic activities were detected in mammary tissue extracts. A novel 26K cell-associated caseinase—a serine arginine-esterase—was modulated at different stages of mammary development. The other caseinases, at 92K and a larger than 100K, were not developmentally regulated. To find out which cell type produced the proteinases in the mammary gland, we isolated and cultured mouse mammary epithelial cells. Cells cultured on different substrata produced the full spectrum of gelatinases and caseinases seen in the whole gland thus implicating the epithelial cells as a major source of these enzymes. Analysis of proteinases secreted by cells grown on a reconstituted basement membrane showed that gelatinases were secreted preferentially in the direction of the basement membrane. The temporal pattern of expression of these proteinases and the basal secretion of gelatinases by epithelial cells suggest their involvement in the remodelling of the extracellular matrix during the different stages of mammary development and thus modulation of mammary cell function.


1925 ◽  
Vol 42 (2) ◽  
pp. 179-191 ◽  
Author(s):  
J. Hamilton Crawford ◽  
J. N. J. Hartley

1. There is a marked individual variation in the histological structure of the thyroid gland of rabbits examined at the same season under standard conditions. Although the microscopic appearance varies in different rabbits, the structure of the two lobes in the same animal does not differ. The variations are seen principally in the size and shape of the vesicles and in the quantity and character of the colloid. 2. With one lobe as a control no histological changes in the other lobe have been observed following section or stimulation of either the cervical sympathetic or the vagus and its branches.


1989 ◽  
Vol 67 (2-3) ◽  
pp. 152-162 ◽  
Author(s):  
Melvyn S. Soloff ◽  
Mats A. Fernström ◽  
Martha J. Fernström

The addition of oxytocin to minces of rat mammary gland preincubated with (3H)myo-inositol stimulated the formation of inositol phosphate (IP) in both lactating and regressed glands. Stimulation was about 4 times greater in regressed tissue, consistent with an oxytocin effect on myoepithelial cells, which are enriched relative to epithelial cells during regression. The stimulation of IP formation was agonist specific, as shown with several oxytocin analogs. Arginine vasopressin (AVP), however, was more than twice as potent as oxytocin in stimulating IP formation in regressed tissue. Both V1- and V2-selective AVP receptor antagonists inhibited the stimulation of IP formation by oxytocin. The V1-selective antagonist was about 10 times more inhibitory than the V2-selective antagonist. [3H]AVP was bound to plasma membranes from the mammary gland of the lactating rat with an apparent Kd of about 0.7 nM and Bmax of 54.6 fmol/mg protein. These values were comparable with those found for AVP receptors of kidney plasma membranes. Our results suggest that the stimulation of IP formation in rat mammary gland by oxytocin occurs through occupancy of AVP, and not oxytocin, receptor sites. A second aspect of these studies was to determine if a recently developed iodinated antagonist of oxytocin-induced uterine contractions could be used as a specific probe for oxytocin receptors in the rat mammary gland. Under steady state conditions, [125I]d(CH2)51[Tyr(Me)2,Thr4,Tyr-NH29]OVT was bound to a single class of independent binding sites in mammary gland plasma membrane from lactating rats with an apparent Kd of 65 pM and Bmax of 225 fmol/mg protein. Noniodinated antagonist had an affinity about 150 times less than the monoiodinated form. The affinity of binding sites for AVP was 10 times greater than the noniodinated antagonist and 2.4 times greater than oxytocin. In view of the presence of AVP receptors in mammary tissue, these findings suggested that the iodinated antagonist binds to AVP receptors. However, comparison of the binding of iodinated antagonist to plasma membranes from the lactating mammary gland with kidney medulla and liver, target sites for AVP, showed that binding was specific for the mammary gland and hence oxytocin receptors. The concentration of oxytocin receptors in mammary gland, as determined by [125I]d(CH2)51[Tyr(Me)2,Thr4,Tyr-NH29]OVT binding, was 4 times greater than the concentration of high-affinity AVP receptors, as determined by [3H]AVP binding. The high affinity, specificity, and specific activity of the iodinated antagonist should make it very useful in further studies to discriminate between oxytocin and AVP receptors, demonstrate oxytocin receptors with small amounts of samples, perform autoradiographic studies with short-term exposures, and to purify oxytocin receptors.Key words: oxytocin, vasopressin, receptor, mammary gland, antagonist.


1992 ◽  
Vol 263 (6) ◽  
pp. E1077-E1085 ◽  
Author(s):  
M. Rakopoulos ◽  
S. J. Vargas ◽  
M. T. Gillespie ◽  
P. W. Ho ◽  
H. Diefenbach-Jagger ◽  
...  

Production of parathyroid hormone-related protein by the rat mammary gland in pregnancy and lactation. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E1077-E1085, 1992.--Production of parathyroid hormone-related protein (PTHrP) by the mammary gland of Sprague-Dawley rats has been examined using immunohistochemistry and in situ hybridization to detect PTHrP and PTHrP mRNA, respectively. PTHrP and PTHrP mRNA could be demonstrated in nests of epithelial cells of the developing mammary gland at day 14 of pregnancy and in the epithelial secretory cells lining the alveoli during the latter stages of pregnancy and during lactation. A specific radioimmunoassay was also used to measure the concentration of PTHrP secreted in the milk throughout lactation. The concentration of PTHrP in milk was relatively low initially but increased during the latter stages of lactation, whereas calcium concentrations remained virtually constant throughout lactation. No correlation was found between the concentrations of calcium and PTHrP in rat milk. These results show that PTHrP is present in rat milk and also in mammary tissue before parturition, and therefore it may assist in the development of the mammary gland during pregnancy.


2006 ◽  
Vol 263 (6) ◽  
pp. E1077-E1085 ◽  
Author(s):  
M. Rakopoulos ◽  
S. J. Vargas ◽  
M. T. Gillespie ◽  
P. W. Ho ◽  
H. Diefenbach-Jagger ◽  
...  

Production of parathyroid hormone-related protein by the rat mammary gland in pregnancy and lactation. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E1077-E1085, 1992.--Production of parathyroid hormone-related protein (PTHrP) by the mammary gland of Sprague-Dawley rats has been examined using immunohistochemistry and in situ hybridization to detect PTHrP and PTHrP mRNA, respectively. PTHrP and PTHrP mRNA could be demonstrated in nests of epithelial cells of the developing mammary gland at day 14 of pregnancy and in the epithelial secretory cells lining the alveoli during the latter stages of pregnancy and during lactation. A specific radioimmunoassay was also used to measure the concentration of PTHrP secreted in the milk throughout lactation. The concentration of PTHrP in milk was relatively low initially but increased during the latter stages of lactation, whereas calcium concentrations remained virtually constant throughout lactation. No correlation was found between the concentrations of calcium and PTHrP in rat milk. These results show that PTHrP is present in rat milk and also in mammary tissue before parturition, and therefore it may assist in the development of the mammary gland during pregnancy.


2008 ◽  
Vol 10 (5) ◽  
pp. 466-471 ◽  
Author(s):  
Rita Payan-Carreira ◽  
Ana C. Martins-Bessa

The aim of this study is to characterise the feline mammary echotexture using B-mode ultrasonography, which is not routinely used to examine the feline mammary gland. Using a 5–9 MHz linear transducer the ultrasonographic appearance of non-stimulated and stimulated mammary glands was determined in 35 mature intact non-pregnant, pregnant and lactating queens aged from 16 months to 8 years. In intact non-pregnant queens, mammary glands are fairly underdeveloped and on the ultrasonograms they appear with a regular hypoechoic texture and generally show a thickness of less than 2.0 mm. The stimulated mammary tissue typically presents a more hyperechoic appearance compared to the non-stimulated gland and a fine granular echotexture. Maximum echogenicity of the mammary gland is reached during lactation. In late pregnancy, the mammary glands reach 6–9 mm in thickness. During lactation, the size of the glands depends on the existence of a suckling stimulus, with the suckled glands reaching about 11 mm in thickness. Ductal structures can only be imaged during late pregnancy and lactation. Ultrasonographic evaluation of the feline mammary gland can become a valuable diagnostic tool to characterise physiological changes and may further contribute to a better characterisation of diseased mammary tissue.


2001 ◽  
Vol 27 (3) ◽  
pp. 349-356 ◽  
Author(s):  
MC Barber ◽  
L Pooley ◽  
MT Travers

Expression of a variant acetyl-CoA carboxylase-alpha (ACC-alpha) mRNA encoding an isozyme either comprising (+24nt) or lacking (Delta24nt) an eight amino acid domain proximal to the Ser-1200 phosphorylation motif has been investigated in ovine and rat mammary tissue throughout pregnancy and lactation. The ratio of the Delta24nt mRNA: +24nt mRNA in ovine tissues varied from 0.1-0.25 (spleen, lung, muscle, heart, adipose tissue, brain) to 0.6-0.8 (pancreas, liver, kidney) to approximately 5.0 (lactating mammary gland). The sixfold increase in total ACC-alpha mRNA expression in mammary gland during lactation was due entirely to a tenfold increase in the level of the Delta24nt species as the level of expression of the +24nt species remained unaltered between pregnancy and lactation. This mode of expression of the +24nt and Delta24nt mRNAs was similar in rat mammary gland. Between day 20 of pregnancy and day 4 of lactation the ratio of the Delta24nt : +24nt mRNA increased from 2:1 to 10-20:1. Forced involution reduced the ratio of the two mRNAs to levels observed throughout pregnancy. Treatment of lactating rats with bromocryptine reduced the ratio of the Delta24nt : +24nt mRNA to relative levels observed after forced involution, suggesting that the exonic splicing responsible for the generation of the two mRNA isoforms is prolactin responsive.


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