Prolactin stimulation

Gonzalez-Mariscal, G., Chirino, R. and Hudson, R. (1994) Prolactin stimulates emission of nipple pheromone in ovariectomized New Zealand white rabbits. Biol. Reprod. 50, 373-376. 

FIGURE 8.4 The Bronson model of priming pheromone actions in rodents. Chemical signaling between males and females constitutes a feedback mechanism that results in accelerated maturation and reproduction. This, in turn, permits the mice to adjust their reproduction and population size quickly to respond to environmental conditions such as sudden food abundance at harvest time. FSH, follicle-stimulating hormone LH, luteinizing hormone PRL, prolactin. Stimulation and inhibition are marked by - - and —, respectively. (From Bronson and Coquelin, 1980.)... 

J. A. Rillema, D. L. Rowady, Characteristics of the prolactin stimulation of iodide uptake into mouse mammary gland explants, Proc. Soc. Expl. Biol. Med., 215 (1997), 366 369. 

Polyclonal antibodies have been prepared against partially purified rabbit mammary gland receptors [42-44], and have been used to demonstrate that the receptors really are involved in mediating the biological actions of prolactin. Anti-receptor antibodies that blocked binding of labelled prolactin were able to inhibit prolactin-stimulated casein synthesis and amino acid transport in rabbit mammary gland explants in vitro [43,45] (Fig. 4). They had no effect on the actions of insulin... 

Among its effects on the epithelial cells of the mammary alveoli prolactin stimulates the production of the major milk proteins casein and lactalbumin [64,66-69,74-76]. Mouse mammary explants incubated in vitro with insulin and a corticosteroid produce very little of these proteins, but addition of prolactin to the culture medium induces their synthesis 10-20-fold within about 24 h. As has already been discussed, there is some uncertainty about the importance of glucocor-... 

A possible involvement of polyamines in the response has been suggested. Prolactin stimulated ornithine decarboxylase activity in Nb2 cells [109]. A specific inhibitor of this enzyme partially blocked the actions of lactogenic hormones on Nb2 cell proliferation [110], and addition of polyamines (putrescine, spermidine or spermine) restored normal growth. However, polyamines alone had no effect on Nb2 cell proliferation, suggesting that they are not the sole or major factors involved in mediating the actions of prolactin on cell growth. 

The rapid (i.e. less than 4 h) activation of TH in the median eminence by prolactin that constitutes the tonic component of prolactin stimulation does not require protein synthesis, but is probably associated with effects on the catalytic properties of this enzyme. Pasqualini and coworkers (1994) demonstrated in vitro that prolactin acts directly on TH in the mediobasal hypothalamus to trigger the phosphorylation of this enzyme. This effect, possibly mediated by protein kinase C, makes the enzyme less susceptible to inhibition by newly synthesized DA. That is, prolactin-induced short-term activation of TH results from the removal of end-product inhibition of the enzyme. Conversely, the acute reduction in TH activity measured in vitro in median eminence removed from rats 4 h after administration of bromocriptine is prevented by the coadministration of prolactin (Arbogast and Voogt, 1995). This can also be prevented by an inhibitor of phosphoprotein phosphatases, suggesting that rapid suppression of TH activity secondary to the bromocriptine-induced hypoprolactinemia may also result from dephosphorylation of the enzyme. 

Estrogen-containing formulations can further promote neuroleptic drug-induced prolactin stimulation (623). 

Antipsychotics Phenothiazines Metoclopramide Domperidone Prolactin stimulators MethyIdopa Reserpine... 

Prolactin Stimulates milk production in mammary glands and assists in the regulation of the male reproductive system... 

Stimulates both thyrotropin (TSH) and prolactin Stimulates both luteinizing hormone (LH) and follicle-stimulating hormone (FSH)... 

Some pituitary hormones stimulate target tissue directly. For example, prolactin stimulates mammary glands to produce milk. 

I, 25-(0H)2D3 are made. Blood levels of 1,25-(OH)2D3 have been reported to be high during these periods It has also been reported that growth hormone and prolactin stimulate the 25-OH-D3-l-hydroxylase These reports remain to... 

High oxytocin levels and prolactin stimulate the breasts to make milk. Oxytocin also produces feelings of relaxation and nurturing behavior toward the baby. 

Asnis GM, Sachar EJ, Halbreich U, Ostrow LC et al. 1981 The prolactin-stimulating potency of reserpine in man. Psychiatry Res 5 39-45... 

Steroids - Large doses of estrogen inhibit prolactin stimulation of mammary tumor growth as demonstrated by the effect of estradiol benzoate to DMBA-lnduced mammary adenocarcinomas in female rats. Estrogen may be involved in transport of RNA from nucleus to cytoplasm. Specific binding of estradiol within the nucleus is confined to hormone-dependent tumors... 

The menstrual cycle is controlled by three protein hormones from the pituitary gland. The follicle-stimulating hormone (FSH) induces the growth of the egg, and the luteinizing hormone (LH) induces its release from the ovaries and the formation of an ovarian tissue called the corpus luteum. The third pituitary hormone (luteotropic hormone, also called luteotropin or prolactin), stimulates the corpus luteum and maintains its function. 

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