Stimulation and inhibition tests are proposed for evaluating prolactin secretion. Thyrotropin-releasing hormone (TRH) stimulates the release of prolactin from the pituitary. Chlorpromazine acts presumably at the hypothalamic level to increase prolactin secretion. L-Dopa (D,L-alpha-hydrazino-alpha-methyl-beta-[3,4-di-hydroxyphenyl]) has the opposite effect; it inhibits prolactin secretion and ma...

In male fishes, birds and mammals, increased prolactin secretion is thought to play a role in species showing paternal behaviours. This hypothesis was investigated in the striped mouse (Rhabdomys pumilio). This paper compares serum prolactin levels in 71 free-living male striped mice following three different reproductive tactics: (i) paternal group-living breeders, (ii) alloparental philopatri...

The effects of progesterone on lactose synthesis activity and changes in mammary gland cells were studied in pseudopregnant rabbits simultaneously treated with prolactin. The injection of progesterone alone on Days 15 and 17 of pseudopregnancy decreased the activity of lactose synthetase (LSA) and galactosyl transferase (GTA), while the administration of prolactin for 2-4 days increased their ...

Synthesis of prolactin was measured in a clonal strain of functional pituitary cells in culture by incubating the cells with [sH]leucine; labeled prolactin was separated from the other labeled proteins by specific immunoprecipitation followed by dissociation with sodium dodecyl sulfate and disc gel electrophoresis. Accumulation of labeled prolactin in the cells was linear for at least 1 hour; l...

Prolactin is unique among the anterior pituitary hormones in that it is under tonic inhibitory control by the hypothalamus. There is much evidence that the major prolactin inhibitory factor is dopamine [l-31. However, there are a number of physiological stimuli of prolactin secretion which can ‘override’ the effect of dopamine and one of the most important of these is oestrogen. Oestrogens are ...

Prolactin plays an important role in mediating parental care in birds, but little is known about changes in prolactin levels when animals disrupt their reproductive behaviour during emergency life-history stages. We investigated the variation of prolactin levels with breeding stage, sex, body condition and as a response to a standardized acute stressor in a small short-lived bird, the Eurasian ...

Receptors for human, simian, ovine, bovine and murine prolactin, human growth hormone and human placental lactogen have been identified in plasma-membrane-containing subcellular particles isolated from rabbit mammary glands. The association and dissociation of (125)I-labelled prolactin are time- and temperature-dependent processes, both being maximal at 37 degrees C. (125)I-labelled prolactin p...

Prolactin has been shown to stimulate intestinal calcium absorption, increase bone turnover, and reduce renal calcium excretion. The small intestine, which is the sole organ supplying new calcium to the body, intensely expresses mRNAs and proteins of prolactin receptors, especially in the duodenum and jejunum, indicating the intestine as a target tissue of prolactin. A number of investigations ...