No Association of Prolactin Receptor (PRLR) Gene and litter size in Gaddi Goat Breed Reared under Migratory System in Western Himalayan Ranges of Himachal Pradesh

Gaddi is the predominant Indian goat breed also known as “White Himalayan goat”, constituting 60-65% of total goats in the state of Himachal Pradesh. The polymorphism of prolactin receptor (PRLR) gene was found to have relationship with prolificacy in goats. In present study, polymorphism of intron 2 region of PRLR gene was investigated in Gaddi goats (n = 89) using PCR-SSCP and DNA sequencing approach. PCR-SSCP assay of 176 bp amplicon of intron 2 region of PRLR gene revealed polymorphism with three types of genotypes viz., AA, AB and BB with genotypic frequencies as 0.31, 0.55 and 0.14, respectively. The allelic frequency of alleles A and B were 0.59 and 0.41, respectively in all the screened goat population. Genetic diversity analysis revealed the value of Ne, Hobs, Hexp and PIC were 1.96, 0.52, 0.49 and 0.37, respectively. The Ne and Hobs values also indicated that sufficient genetic variation exists at the studied locus. FIS estimate was observed as -0.15 indicating heterozygous excess at studied locus. DNA sequencing of amplified product revealed one nucleotide mutation (T92C) in intron 2 region of PRLR gene. The mean litter size in AA, AB and AB genotypes were 1.27±0.12, 1.41±0.09 and 1.84±0.26, respectively. No significant (P>0.05) associations of PRLR genotypes with litter size were observed. Effect of season and parity were also found to be non-significant (P>0.05) on litter size. Consequently, the study on additional data based on more number of animals in diversified flock should be carried out for future association studies.

Progress of prolactin in regulating the function of pancreatic β cells / 中华内分泌代谢杂志

Prolactin is a polypeptide hormone that regulates cell growth and development. Recent studies have shown that prolactin is involved in the regulation of glucose metabolism and is closely related to blood glucose homeostasis. This paper is to review the research progress of prolactin in islet β cells, including the understanding of prolactin and its receptor, the associations of prolactin with glucose metabolism, and the proliferation, apoptosis and secretion of pancreatic beta cells.

Effects of acupuncture combined withgranule on breast tissue, prolactin and receptor expression in rats with mammary gland hyperplasia / 中国针灸

<p><b>OBJECTIVE</b>To observe the effects of acupuncture combined withgranule on breast tissue, prolactin(PRL) and prolactin receptor (PRLR) expression in rats with mammary gland hyperplasia (MGH), and to explore its action mechanism to provide reference for clinical treatment of MGH.</p><p><b>METHODS</b>Fifty-five female SD rats were randomly divided into a blank group, a model group, an acupuncture group, a Rule granule group and a combination group. Except the blank group, the rats in the remaining groups were treated with combined stimulation of estrogenic and progestational hormone to establish MGH model. After model establishment, the rats in the acupuncture group were treated with acupuncture at Plan A of "Tianzong" (SI 11), "Ganshu" (BL 18), "Zusanli" (ST 36) and Plan B of "Wuyi" (ST 15), "Hegu" (LI 4), "Danzhong" (CV 17). Each plan was selected for one acupuncture treatment, and two plans were used alternately. The rats in the Rule granule group were treated with oral administration of granule, 3 mL per times. The rats in the combination group were treated with the samegranule, followed by acupuncture, once a day. After consecutive 30-day treatment, blood sample was collected from abdominal aorta; ELISA method was applied to measure the contents of PRL; the HE slice of mammary gland was observed under light microscope; the SABC immunohistochemical method was applied to measure the positive expression of PRLR.</p><p><b>RESULTS</b>The morphology of breast tissue in the model group was consistent with MGH. Compared with the blank group, the serum PRL and the expression of PRLR were increased significantly in the model group (both<0.01). Compared with the model group, the hyperplasia of mammary gland in each treatment group was improved, and serum PRL and expression of PRLR were significantly reduced (<0.05,<0.01), which were more significant in the combination group (both<0.05).</p><p><b>CONCLUSION</b>Acupuncture,granule and its combination could effectively treat MGH, which is likely to reduce the level of serum PRL and inhibit the binding of PRL to PRLR, as a result, the level of Eis indirectly inhibited, and the hyperplastic mammary gland is recovered. Compared with acupuncture orgranule, the combination of both has better overall efficacy.</p>

Interactions between prolactin and kisspeptin to control reproduction

ABSTRACT Prolactin is best known for its effects of stimulating mammary gland development and lactogenesis. However, prolactin is a pleiotropic hormone that is able to affect several physiological functions, including fertility. Prolactin receptors (PRLRs) are widely expressed in several tissues, including several brain regions and reproductive tract organs. Upon activation, PRLRs may exert prolactin’s functions through several signaling pathways, although the recruitment of the signal transducer and activator of transcription 5 causes most of the known effects of prolactin. Pathological hyperprolactinemia is mainly due to the presence of a prolactinoma or pharmacological effects induced by drugs that interact with the dopamine system. Notably, hyperprolactinemia is a frequent cause of reproductive dysfunction and may lead to infertility in males and females. Recently, several studies have indicated that prolactin may modulate the reproductive axis by acting on specific populations of hypothalamic neurons that express the Kiss1 gene. The Kiss1 gene encodes neuropeptides known as kisspeptins, which are powerful activators of gonadotropin-releasing hormone neurons. In the present review, we will summarize the current knowledge about prolactin’s actions on reproduction. Among other aspects, we will discuss whether the interaction between prolactin and the Kiss1-expressing neurons can affect reproduction and how kisspeptins may become a novel therapeutic approach to treat prolactin-induced infertility.

Evidence of a role for prolactin as regulators of ovarian follicular development in goose

Background Prolactin (PRL) regulates development and reproduction, and its effects are mediated by the prolactin receptor (PRLR). In order to clarify the role of PRLR and PRL in the process of follicular development in the goose ovary, the level of PRLR mRNA expression in the ovary and follicles of the Sichuan white goose was determined, as well as the PRL concentration in ovarian follicles. Results The level of PRLR mRNA in the hierarchical follicles (HFs) initially increased, and subsequently decreased, whereas PRLR expression was initially low and later increased in postovulatory follicles (POFs). The level of PRLR mRNA expression was the highest in the F4 follicles, and lowest in the F1 follicles in all of the examined follicles. Compared with the level of PRLR mRNA expression in the small white follicles (SWFs), the level of PRLR mRNA was 2.86- and 1.44-fold higher in the F4 and small yellow follicles (SYFs), respectively (P < 0.05). The level of PRLR mRNA expression in the F4 follicles was highest (P < 0.05) in HFs. The highest PRL concentration in all of the examined samples was observed in SYFs and F1, with concentration of 6162 mLU/g and 6197 mLU/g, respectively. The PRL concentration in SYFs was significantly higher compared with SWFs (P < 0.05). Conclusions The change of PRL concentration was similar to the PRLR mRNA expression level in preovulatory follicles. These results suggest that the PRL mediated by the PRLR plays a stimulatory role in the SWF to SYF transition.

Genital Sensory Stimulation Shifts Estradiol Intraoviductal Signaling from Nongenomic to Genomic Pathways, Independently from Prolactin Surges

Estradiol (E2) accelerates oviductal egg transport through nongenomic pathways involving oviductal protein phosphorylation in non-mated rats, and through genomic pathways in mated rats. Here we investigated the ability of cervico-vaginal stimulation (CVS) to switch the mode of action of E2 in the absence of other male-associated components. Pro-estrous rats were subjected to CVS with a glass rod and 12 hours later were injected subcutaneously with E2 and intrabursally with the RNA synthesis inhibitor Actinomycin D or the protein phosphorylation inhibitor H-89. The number of eggs in the oviduct, assessed 24 h later, showed that Actinomycin D, but not H-89 blocked the E2-induced egg transport acceleration. This clearly indicates that CVS alone, without other mating-associated signals, is able to shift E2 signaling from nongenomic to genomic pathways. Since mating and CVS activate a neuroendocrine reflex that causes iterative prolactin (PRL) surges, the involvement of PRL pathway in this phenomenon was evaluated. Prolactin receptor mRNA and protein expression in the rat oviduct was demonstrated by RT-PCR and Western blot, but their levels were not different on day 2 of the cycle (C2) or pregnancy (P2). Activated ST AT 5a/b (phosphorylated) was detected by Western blot on P2 in the ovary, but not in the oviduct, showing that mating does not stimulate this PRL signalling pathway in the oviduct. Other rats subjected to CVS in the evening of pro-estrus were treated with bromoergocriptine to suppress PRL surges. In these rats, H-89 did not block the E2-induced acceleration of egg transport suggesting that PRL surges are not essential to shift E2 signaling pathways in the oviduct. We conclude that CVS is one of the components of mating that shifts E2 signaling in the oviduct from nongenomic to genomic pathways, and this effect is independent of PRL surges elicited by mating.