The role of prolactin in the reactivation of hair follicles in relation to moulting in cashmere goats

1994 ◽  
Vol 143 (3) ◽  
pp. 441-448 ◽  
Author(s):  
P Dicks ◽  
A J F Russel ◽  
G A Lincoln
Keyword(s):  
Prolactin Secretion ◽  
Hair Follicles ◽  
Plasma Prolactin ◽  
Dose Rates ◽  
Significant Difference ◽  
Natural Photoperiod ◽  
Cashmere Goats ◽  
Ovine Prolactin ◽  
Voluntary Food Intake

Abstract The effects of the suppression or elevation of plasma prolactin concentrations in spring on the timing of the reactivation of the hair follicles and the timing of the spring moult were investigated in cashmere goats. Thirty eight adult female goats, housed under conditions of natural photoperiod at 55°55′N from mid-December until May, were allocated to four groups starting on 5 January: ten served as untreated controls, eight received 2 mg ovine prolactin subcutaneously every 12 h for 7 weeks (PRL), twelve received 35 mg bromocriptine intramuscularly every 14 days for 17 weeks (BCR) and eight received injections of both ovine prolactin and bromocriptine at the above dose rates for 7 weeks (PRL+BCR). In the PRL group there was an earlier reactivation of the secondary hair follicles (PRL vs control, proportion of secondary follicles in anagen, weeks 1–5, P<0·01) associated with an earlier moult of secondary fibres (cashmere) but no significant difference in the activity of the primary hair follicles. In the BCR group there was a delay in the reactivation of both the secondary and primary hair follicles (BCR vs control, proportion of secondary and primary hair follicles in anagen, weeks 5–13, P<0·01) and a delay in the moult. In the PRL+BCR group there was an early reactivation and moult similar to the PRL group. Voluntary food intake (VFI) and liveweight were also measured. Only in the BCR group was there a decrease in VFI compared with the controls but with no effect on liveweight. It was concluded that the seasonal increase in prolactin secretion which normally occurs in spring is causally involved in the reactivation of primary and secondary hair follicles and moulting in cashmere goats. Journal of Endocrinology (1994) 143, 441–448

The effect of melatonin implants administered from December until April, on plasma prolactin, triiodothyronine and thyroxine concentrations and on the timing of the spring moult in cashmere goats

1995 ◽  
Vol 60 (2) ◽  
pp. 239-247 ◽  
Author(s):  
P. Dicks ◽  
A. J. F. Russel ◽  
G. A. Lincoln
Keyword(s):  
Peak Plasma ◽  
Live Weight ◽  
Prolactin Secretion ◽  
Hair Follicles ◽  
Plasma Prolactin ◽  
Guard Hair ◽  
Continuous Release ◽  
Melatonin Administration ◽  
Cashmere Goats ◽  
Harvesting Efficiency

AbstractThe effect of melatonin implants administered to cashmere goats in the winter, on plasma prolactin, triiodothyronine (T3) and thyroxine (T4) concentrations and the timing of the spring moult, was studied with the objective of identifying a method of manipulating the timing of the spring moult and increasing fibre harvesting efficiency. The effect of similar melatonin implants on prolactin concentration when administered in the increasing daylength of spring, was also measured.In the first experiment, using 20 juvenile and 20 adult female cashmere goats, half the animals of each group received continuous release implants of melatonin (18 mg) on 11 December, 1 February and 1 April. In the adult goats the treatment significantly advanced by 7 weeks the time at which peak plasma prolactin concentrations were attained (P < 0·001) and advanced the onset (P < 0·001) of the peak. The treatment also resulted in an advance of the spring moult of cashmere in the adult goats (P < 0·01) and in an earlier initiation (P < 0·01) of the growth of both guard hair and cashmere as judged by histological examination of primary and secondary hair follicles. In the juvenile goats there were no significant effects of melatonin administration on plasma prolactin concentrations, the timing of the moult, or on any of the histological measurements compared with the controls. There were no significant effects on live weight or circulating concentrations of T3 and T4 in either age group. In the second experiment, the administration of one melatonin implant (18 mg) to three adult goats on 1 April caused a significant reduction in plasma prolactin concentrations (P < 0·05) over a period of 3 weeks compared with concentrations observed in four untreated goats.It is concluded that treatment with melatonin implants is effective in modifying the timing of the seasonal cycle in prolactin secretion in adult cashmere goats and causing corresponding changes in hair follicle activity. However, since the treatment initiated in December caused an advance rather than a delay in the normal spring rise in plasma prolactin concentrations, it is evident that the repeated melatonin implant protocol used in this experiment cannot be used to delay the onset of the spring moult and thus facilitate the harvesting of cashmere.

Hormonal manipulation of cashmere growth and shedding

1990 ◽  
Vol 1990 ◽  
pp. 58-58
Author(s):  
Pamela Lynch ◽  
A.J.F. Russel
Keyword(s):  
Hair Follicles ◽  
Seasonal Cycles ◽  
Plasma Prolactin ◽  
Cashmere Goat ◽  
Guard Hair ◽  
Outer Coat ◽  
Hormonal Manipulation ◽  
Long Duration ◽  
Evolutionary Response ◽  
Cashmere Goats

Cashmere goats exhibit seasonal cycles in hair growth and moulting which are an evolutionary response to seasonal changes in temperature. The winter coat of the cashmere goat consists of two types of fibre, a coarse outer coat of guard hair produced by the primary hair follicles and a dense Insulating undercoat of cashmere (<19 microns diameter) produced by the smaller and more numerous secondary follicles. In the Spring, under the influence of Increasing daylength, both guard hairs and cashmere are shed from the follicles and a sparse coat of guard hair remains.The efficiency of harvesting fibre from cashmere goats is limited by the season of the moult, the long duration of the moulting period and by the variability between individual animals in the timing of the moult. Lynch & Russel (1989) reported that an earlier rise in plasma prolactin was associated with an advance In the onset of the spring moult in the cashmere goat.

Involvement of the adrenal gland in the suckling-induced decrease in LH and FSH secretion and the concomitant increase in prolactin secretion in the rat

1990 ◽  
Vol 125 (2) ◽  
pp. 279-285 ◽  
Author(s):  
K. Taya ◽  
S. Sasamoto
Keyword(s):  
Adrenal Gland ◽  
Ovarian Function ◽  
Plasma Concentrations ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Luteal Function ◽  
Follicular Maturation ◽  
High Concentrations ◽  
Ovulatory Follicles

ABSTRACT The role of the adrenal gland in the regulation of gonadotrophin and prolactin secretion in the lactating rat was investigated. Changes in secretion of LH, FSH, prolactin, ACTH, β-lipotrophin (β-LPH), inhibin, corticosterone and progesterone after adrenalectomy were examined during the second half of lactation. Follicular maturation was determined by the ability of the follicles to ovulate in response to 10IU human chorionic gonadotrophin (hCG). Adrenalectomy on day 10 of lactation prevented an increase in plasma concentrations of LH and FSH in response to ovariectomy performed at the same time as adrenalectomy, and markedly stimulated secretion of ACTH, β-LPH and prolactin. Adrenalectomy reduced the number of follicles capable of ovulating in response to hCG. Concentrations of inhibin and progesterone in the plasma significantly decreased after adrenalectomy, indicating that development of ovulatory follicles and luteal function had been suppressed. Abolishing the increase in plasma concentrations of LH and inducing a decrease in FSH in the plasma by adrenalectomy therefore prevented maturation of a new set of follicles usually seen during the second half of lactation in rats. The decrease in plasma concentrations of LH also inhibited the ability of the corpus luteum to secrete progesterone, although high concentrations of plasma prolactin were maintained in adrenalectomized lactating rats. These results indicate that the pituitary-adrenal system is capable of influencing the maintenance of a normal secretion of gonadotrophin and prolactin as well as the maintenance of ovarian function during lactation in the rat. Journal of Endocrinology (1990) 125, 279—285

Role of the adrenal cortex in chronic stress-induced inhibition of prolactin secretion in male rats

1989 ◽  
Vol 120 (2) ◽  
pp. 269-273 ◽  
Author(s):  
A. López-Calderón ◽  
C. Ariznavarreta ◽  
M. D. Calderón ◽  
J. A. F. Tresguerres ◽  
M. I. Gonzalez-Quijano
Keyword(s):  
Adrenal Cortex ◽  
Chronic Stress ◽  
Immobilization Stress ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Prolactin Secretion ◽  
Male Rats ◽  
Prolonged Release ◽  
Plasma Prolactin

ABSTRACT The response of prolactin to chronic stress in intact, adrenalectomized and adrenomedullectomized male rats was studied. Immobilization stress in intact animals induced a significant increase in plasma concentrations of prolactin after 20 and 45 min and a significant decrease when the rats were submitted to chronic restraint (6 h daily for 4 days). Five weeks after adrenomedullectomy, plasma prolactin and corticosterone responses to chronic stress were not modified. In contrast, the inhibitory effect of chronic stress on prolactin secretion was totally suppressed by adrenalectomy. When treated with dexamethasone during the 4 days of restraint, adrenalectomized stressed rats showed similar plasma concentrations of prolactin to the intact stressed rats. These data indicate that the adrenal cortex is able to play an inhibitory role on prolactin secretion during stress only through a prolonged release of glucocorticoids. Journal of Endocrinology (1989) 120, 269–273

Seasonal patterns of growth, voluntary food intake and plasma concentrations of prolactin, insulin-like growth factor-1, LH and gonadal steroids in male and female pre-pubertal red deer (Cervus elaphus) reared in either natural photoperiod or constant daylength

1996 ◽  
Vol 62 (3) ◽  
pp. 605-613 ◽  
Author(s):  
C. L. Adam ◽  
C. E. Kyle ◽  
P. Young
Keyword(s):  
Growth Factor ◽  
Food Intake ◽  
Red Deer ◽  
Plasma Testosterone ◽  
Plasma Prolactin ◽  
Insulin Like Growth Factor ◽  
Male And Female ◽  
Natural Photoperiod ◽  
Lh Secretion ◽  
Voluntary Food Intake

AbstractRed deer calves were reared from birth to 16 months in either constant intermediate 12L: 12D daylength (ID) or in natural photoperiod (NP) (four males and four females per group) to investigate effects on the somatotropic and reproductive axes, and to compare responses between the seres. Measurements, starting from 3 months (September), were made each week of live weight (LW), voluntary food intake (VFI), plasma prolactin, plasma insulin-like growth factor-1 (IGF-1), and plasma progesterone (females), and every 2 months of pulsatile LH secretion, plasma testosterone (males), responses to exogenous GnRH, and antler development (males).Both sexes in ID compared with NP had significantly higher LW gain (males, P < 0·001; females, P < 0·01) and VFI (P < 0·001) between winter solstice (WS) and spring equinox (SE), and VFI between SE and summer solstice (SS) (males, P < 0·05; females P < 0·01). Both sexes had significantly lower plasma prolactin concentrations in ID than in NP (males, P < 0·05; females, P < 0·01) between SE and SS. However, plasma IGF-1 was only significantly altered in males, being significantly higher in ID than NP between WS and SE (P<0·01). ID and NP females showed no significant differences in pulsatile LH secretion nor in the timing of pubertal ovulation. However, ID compared with NP males at 10 months (just after SE) had higher LH and testosterone pulse frequencies (P < 0·01), and at 12 months (just before SS) had higher mean testosterone concentrations (P < 0·01) and testosterone response to GnRH challenge (P<0·001). ID antlers hardened earlier at 11 months than NP antlers at 14 months (P < 0·001).Thus ID compared with NP in both sexes prevented the winter reduction in growth and appetite and the summer elevation in prolactin secretion, and in males, but not in females, stimulated higher IGF-1 secretion in winter, an earlier increase in LH pulse frequency, and an earlier increase in gonadal steroid production. This study has therefore revealed some intriguing similarities and contrasts in the responses to photoperiod shown by young male and female deer.

scholarly journals Identification of salsolinol in the mediobasal hypothalamus of lactating ewes and its relation to suckling-induced prolactin and GH release

2008 ◽  
Vol 198 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Tomasz Misztal ◽  
Konrad Górski ◽  
Dorota Tomaszewska-Zaremba ◽  
Edyta Molik ◽  
Katarzyna Romanowicz
Keyword(s):  
Anterior Part ◽  
Posterior Part ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Suckling Period ◽  
Mediobasal Hypothalamus ◽  
Blood Samples ◽  
Extracellular Concentration ◽  
Made In

The push–pull perfusions of the infundibular nucleus–median eminence (IN/ME) were made in lactating ewes (n=7) twice, to identify dopamine (DA)-derived salsolinol and the changes in its extracellular concentration in response to suckling. The perfusate collecting period in every ewe consisted of control non-suckling period, 1000–1230 h (five perfusates), and suckling period, 1230–1500 h (next five perfusates). Simultaneously, blood samples were collected from 1000 to 1500 h at 10-min intervals. The perfusate concentrations of salsolinol and DA were measured by HPLC, and plasma prolactin and GH concentrations were assayed by the RIA. Mean concentrations of salsolinol in perfusates collected from the anterior and posterior parts of the IN/ME (according to post-mortem localization of a perfusion site) increased significantly (P<0.05 and P<0.001 respectively) during the suckling period, when compared with those noted during the non-suckling period. While no DA was found in the anterior part, only vestigial amounts of DA were found in a few perfusates collected from the posterior part. Salsolinol was not detected in the IN/ME of ewes 10 weeks after weaning (seasonal anoestrus). Mean plasma prolactin and GH concentrations during suckling were significantly (P<0.001) higher than those noted during the non-suckling period. In conclusion, our current study reveals that salsolinol is present in the IN/ME of lactating ewes and that its extracellular concentration increases during suckling. Moreover, it supports the role of salsolinol as a neurotransmitter involved in the regulatory process of prolactin secretion at least during lactation.

Migratory fat deposition in European quail: a role for prolactin?

1995 ◽  
Vol 146 (1) ◽  
pp. 71-79 ◽  
Author(s):  
T Boswell ◽  
P J Sharp ◽  
M R Hall ◽  
A R Goldsmith
Keyword(s):  
Food Intake ◽  
Body Mass ◽  
Strong Association ◽  
Fat Deposition ◽  
Daily Rhythm ◽  
Plasma Prolactin ◽  
Coturnix Coturnix ◽  
Ad Libitum ◽  
Ovine Prolactin

Abstract The present study addresses the role of prolactin as a regulator of migratory fattening in European quail (Coturnix coturnix). Plasma prolactin levels in captive birds undergoing migratory fattening in an outdoor aviary and in the laboratory were measured by radioimmunoassay with an antibody raised against recombinant-derived chicken prolactin. No strong association between prolactin and migratory fattening was apparent, and prolactin levels were more closely related to daylength, with the highest concentrations being reached on long days. Plasma prolactin profiles were similar in intact and castrated male quail. Prolactin was secreted in a daily rhythm, with the highest concentrations occurring early in the photophase. However, when birds were food-restricted for 50 days during a migratory phase, there was no difference in fat deposition between birds food-deprived for the first half of the daily photophase compared with those deprived for the second half. Fattening was reduced in the food-restricted birds relative to ad libitum-fed controls, but there was no difference in plasma prolactin levels between the groups. Injections of ovine prolactin (4 mg/kg) significantly increased food intake and body mass of birds maintained on long days, but there were no differences in fattening between birds injected in the morning compared with those injected in the afternoon. Collectively, these results do not support a major role for prolactin in the regulation of migratory fat deposition in European quail. Journal of Endocrinology (1995) 146, 71–79

Role of the placenta in the control of the ante-partum surge of prolactin in the rat

1991 ◽  
Vol 130 (3) ◽  
pp. 401-407 ◽  
Author(s):  
D. R. Grattan ◽  
R. L. W. Averill
Keyword(s):  
Early Pregnancy ◽  
Feedback Inhibition ◽  
Dark Period ◽  
Late Pregnancy ◽  
Complete Removal ◽  
Prolactin Secretion ◽  
Placental Lactogen ◽  
Surgical Removal ◽  
Plasma Prolactin

ABSTRACT A nocturnal surge of prolactin secretion occurs in the dark period preceding parturition in the rat. The aim of this study was to examine the role of the placenta in the control of this prolactin surge. Plasma prolactin and progesterone were measured by radioimmunoassay in serial blood samples collected after surgical removal of conceptuses during late pregnancy, and after intracerebroventricular (i.c.v.) injection of placental lactogen (PL) before the prolactin surge. In intact control animals, prolactin secretion remained low until a nocturnal surge of secretion occurred in the dark period preceding parturition, peaking at 269±51 (s.e.m.) μg/l at 03.00 h on day 21. Progesterone levels fell from > 200 nmol/l on day 19 to <40 nmol/l by 12.00 h on day 20 of pregnancy. PL levels during late pregnancy were modified by partial or complete removal of conceptuses at 10.00 h on day 19 of pregnancy. Removal of all but one or two conceptuses did not change the normal pattern of prolactin or progesterone secretion. Removal of all conceptuses, however, induced a large nocturnal surge of prolactin secretion, peaking at 211·7±78 μg/l at 03.00 h on day 20, 24 h earlier than the surge in intact animals. Progesterone levels after removal of all conceptuses fell to <40 nmol/l by 23.00 h on day 19, approximately 12 h before the decline in intact animals. Maintenance of increased progesterone levels after conceptus removal using silicone tubing implants significantly (P <0·05) reduced the peak of the premature prolactin surge to 79·7 ±18 μg/l at 05.00 h on day 20. To determine whether PL could act at the hypothalamic level to inhibit the prolactin surge, human PL was injected into the lateral ventricle. PL injected i.c.v. at 17.00 h on day 7 of pregnancy completely abolished both the expected diurnal and nocturnal prolactin surges in the subsequent 24 h. By contrast, the same treatment on day 20 of pregnancy had no effect on the ante-partum prolactin surge. These results demonstrate two changes in the mechanisms controlling prolactin secretion on the last day of pregnancy compared with prolactin secretion during early pregnancy. First, feedback inhibition of prolactin secretion by PL which occurs at mid-pregnancy was not functional on the last day of pregnancy. Secondly, progesterone which promotes the nocturnal prolactin surges of early pregnancy, inhibited prolactin secretion during late pregnancy. Journal of Endocrinology (1991) 130, 401–407

scholarly journals AB0004 TLR10 SINGLE NUCLEOTIDE POLYMORPHISMS ARE ASSOCIATED WITH HIDRADENITIS SUPPURATIVA IN A CAUCASIAN SPANISH POPULATION (NORTHERN SPAIN)

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1306.1-1306
Author(s):  
M. Calderón-Goercke ◽  
J. G. Ocejo-Vinyals ◽  
J. Irure-Ventura ◽  
M. Gutiérrez-Larrañaga ◽  
M. A. González-Gay ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Hidradenitis Suppurativa ◽  
Hair Follicles ◽  
Genotype Distribution ◽  
Nucleotide Polymorphisms ◽  
Northern Spain ◽  
Research Support ◽  
Single Nucleotide ◽  
Significant Difference

Background:Hidradenitis suppurativa (HS) is a chronic, relapsing inflammatory cutaneous disease affecting terminal hair follicles in apocrine-gland bearing skin. The pathogenesis of HS is still unknown, although increasing evidence suggests that the immune system plays an important role. In order to study the role of innate immunity we analyzed several Toll Like Receptors (TLRs) functional single nucleotide polymorphisms (SNPs). To date, only one previous study focused about the role of TLR4 SNPs in HS showing no association with this disease.Objectives:The main goal of this study was to analyze the role of several TLRs functional SNPs in HS patients and healthy controls, in a Caucasian population from Cantabria (northern Spain).Methods:Through a case-control study, we analyzed the allele and genotype distribution of the SNPs in 106 patients with HS and 278 age and sex matched healthy control subjects for the following SNPs (TLR1 rs5743611 and rs4833095, TLR2 rs5743704 and rs5743708, TLR6 rs5743810, and TLR10 rs11096955, rs11096957 and rs4129009, by Real-Time PCR using a TaqMan assay.Results:We did not find any significant difference in the allelic distribution of the different SNPs between HS patients and controls. Regarding genotypes, only TLR10 rs11096955 (dominant, codominant and overdominant), rs11096957 (dominant, codominant and overdominant) and rs4129009 (codominant and overdominant) showed significant differences between HS patients and controls. However, no association was found when we analyzed the different TLR10 haplotypes.Conclusion:To the best of our knowledge, this is the first study showing an association of TLR10 SNPs with HS.References:[1]González-López MA. J Am Acad Dermatol. 2016; Aug;75(2):329-35.[2]González-López MA. PLoS One. 2018 Jan 4;13(1)[3]Vilanova I. J Eur Acad Dermatol Venereol. 2018 May;32(5):820-824.[4]Durán-Vian C, J Eur Acad Dermatol Venereol. 2019 Nov;33(11):2131-2136.Disclosure of Interests:Monica Calderón-Goercke: None declared, J. Gonzalo Ocejo-Vinyals: None declared, Juan Irure-Ventura: None declared, María Gutiérrez-Larrañaga: None declared, Miguel A González-Gay Grant/research support from: Pfizer, Abbvie, MSD, Speakers bureau: Pfizer, Abbvie, MSD, Iosune Vilanova: None declared, Juan Cantos-Mansilla: None declared, Ricardo Blanco Grant/research support from: AbbVie, MSD, and Roche, Speakers bureau: AbbVie, Pfizer, Roche, Bristol-Myers, Janssen, and MSD, Marcos González-López: None declared

Role of prolactin in the photoperiodic control of moulting in the mink (Mustela vison)

1984 ◽  
Vol 103 (1) ◽  
pp. 9-15 ◽  
Author(s):  
L. Martinet ◽  
D. Allain ◽  
C. Weiner
Keyword(s):  
Physiological Role ◽  
Plasma Prolactin ◽  
Summer Solstice ◽  
Natural Lighting ◽  
Short Day ◽  
Lighting Conditions ◽  
Natural Photoperiod ◽  
Moulting Cycle ◽  
Short Days

ABSTRACT Beginning at the summer solstice adult female mink were maintained in long- or short-day photoperiods and treated with bromocriptine or prolactin. In control females kept under natural lighting conditions the moult coincided with the seasonal decrease in prolactin and resulted in the growth of a dense winter coat which was completed by the end of November. Long days, which slowed the decrease in plasma prolactin relative to animals in the natural photoperiod, induced a more or less complete moult followed by growth of a thin summer coat. On the contrary we observed an accelerated decrease in plasma prolactin concentrations followed by an early and brief moult in females kept under long days but treated with bromocriptine and in females under short days. The growth of a dense winter coat was completed by the end of September in all the females of the short-day group and in six of eleven females treated with bromocriptine. In the other five females, moult was followed by the growth of a summer coat. These results may suggest that the decline of prolactin after the summer solstice is responsible for the onset of the autumn moult, but the early, abbreviated moult and the growth of a winter coat observed in females kept under short days and treated with prolactin do not seem to support this hypothesis. However, the huge non-physiological levels of prolactin measured in the plasma of these females and the appearance of abnormal white under-hairs might suggest that the hormonal balance in this group was completely disturbed by the treatment. The physiological role of prolactin in the seasonal moulting cycle in mink is discussed. J. Endocr. (1984) 103,9–15

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