Effect of Pinealectomy on Prolactin, Testosterone and Luteinizing Hormone Concentration in Plasma of Bull Calves Exposed to 8 or 16 Hours of Light Per Day

Stanisiewski, E.P.; Ames, N. Kent; Chapin, L.T.; Blaze, C. A.; Tucker, H.A.

doi:10.2527/jas1988.662464x

Cited by 14 publications

(5 citation statements)

References 27 publications

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“…However, this regulatory relationship is not as clear cut in cattle. Pinealectomy or melatonin fed/infusion did not affect prolactin plasma concentrations in bull calves (Stanisiewski et al, 1988a and1988b). In contrast, melatonin fed to prepubertal heifers in the middle of LDPP lowered mean serum prolactin by 27%, and decreased DNA content and concentration in mammary parenchyma (Sanchez-Barcelo et al, 1991).…”

Section: Circadian Rhythm and Mammary Function 397mentioning

confidence: 83%

Does the circadian system regulate lactation?

Plaut

Casey

2012

Animal

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Environmental variables such as photoperiod, heat, stress, nutrition and other external factors have profound effects on quality and quantity of a dairy cow's milk. The way in which the environment interacts with genotype to impact milk production is unknown; however, evidence from our laboratory suggests that circadian clocks play a role. Daily and seasonal endocrine rhythms are coordinated in mammals by the master circadian clock in the hypothalamus. Peripheral clocks are distributed in every organ and coordinated by signals from the master clock. We and others have shown that there is a circadian clock in the mammary gland. Approximately 7% of the genes expressed during lactation had circadian patterns including core clock and metabolic genes. Amplitude changes occurred in the core mammary clock genes during the transition from pregnancy to lactation and were coordinated with changes in molecular clocks among multiple tissues. In vitro studies using a bovine mammary cell line showed that external stimulation synchronized mammary clocks, and expression of the core clock gene, BMAL1, was induced by lactogens. Female clock/ clock mutant mice, which have disrupted circadian rhythms, have impaired mammary development and their offspring failed to thrive suggesting that the dam's milk production was not adequate enough to nourish their young. We envision that, in mammals, during the transition from pregnancy to lactation the master clock is modified by environmental and physiological cues that it receives, including photoperiod length. In turn, the master clock coordinates changes in endocrine milieu that signals peripheral tissues. In dairy cows, it is clear that changes in photoperiod during the dry period and/or during lactation influences milk production. We believe that the photoperiod effect on milk production is mediated, in part by the 'setting' of the master clock with light, which modifies peripheral circadian clocks including the mammary core clock and subsequently impacts milk yield and may impact milk composition.Keywords: mammary, lactation, circadian rhythm, photoperiod, metabolism ImplicationsThe circadian system coordinates internal physiological processes in mammals and synchronizes these processes to the animal's environment. We review the literature and discuss recent findings from our laboratory and others that suggest the circadian system regulates lactation, including coordinating changes in the dam's physiology needed to initiate and maintain lactation and mediating the photoperiod effect on milk production. Identification of environmental and physiological inputs that affect genes that control circadian rhythms will enable development of approaches to alter gene expression to maximize production efficiency in farm animals. IntroductionNearly all physiological and behavioral functions of animals are rhythmic including secretion patterns of hormones, sleep-wake cycle, metabolism and core body temperature.A circadian rhythm is a roughly 24-h cycle in the biochemical, physiological or behaviora...

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Section: Circadian Rhythm and Mammary Function 397mentioning

confidence: 83%

Does the circadian system regulate lactation?

Plaut

Casey

2012

Animal

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“…In cattle, daily variations in secretions from the pineal gland are probably not involved in mediating daily rhymicity in prolactin concentrations because pinealectomy does not prevent photoperiod-induced changes in serum prolactin (16,17). Furthermore, administration of melatonin to mimic short or long days does not affect concentrations of prolactin in cattle ( 18).…”

Section: Discussionmentioning

confidence: 99%

Daily Changes in Concentrations of Prolactin in Serum of Prepubertal Bulls Exposed to Short- or Long-Day Photoperiods

Petitclerc

Tucker

1989

Experimental Biology and Medicine

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Early temporal changes in concentrations of prolactin (PRL) in serum after a sudden change in photoperiod and daily responsiveness to PRL-releasing and inhibiting factors were investigated in prepubertal Holstein bull calves exposed to different photoperiods. In calves switched from 8-hr light16-hr dark to 16-hr lighk8-hr dark, there was no observable change in the daily pattern of serum concentrations of PRL after 1, 2, or 4 days. On the other hand, in animals switched from 16-hr lighk8-hr dark to 8-hr light:ls-hr dark, there was a consistent increase in serum PRL from 33.4 ng/ml on Day 0 to maximum values of 57.3, 62.7, and 78.9 ng/ml between 14 and 18 hr after onset of light on Days 1, 2, and 4, respectively. Thus, absence of light allowed expression of a daily rhythm in serum concentrations of PRL that persisted for at least 4 days after the photoperiod switch. There were no differences in L-dopa inhibition of PRL release in animals exposed to 16-hr lighk8-hr dark at 3 or 15 hr after onset of light. However, thyrotropin-releasing hormone-induced release of PRL was greater 3 hr after onset of light (11 hr after onset of dark) compared with release at 9, 15, and 21 hr after onset of light in animals exposed to 16-hr lighk8-hr dark, but not in bulls exposed to 8-hr light:16hr dark. The results provide evidence that the cue for the putative photosensitive period of PRL secretion in cattle may be more closely associated with onset of dark, not onset of light.

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“…Besides PRL, melatonin is another hormone that is closely associated with the photoperiod. Melatonin is released by the pineal gland (Stanisiewski et al, 1988), and its secretion displays a circadian profile and a pulsatile secretory pattern (Critser et al, 1987). In the cow, melatonin concentrations in blood are high during the night and low during daylight .…”

Section: Modulation Of Photoperiods To Accelerate the Involution Processmentioning

confidence: 99%

Invited review: Accelerating mammary gland involution after drying-off in dairy cattle

Zhao

Ponchon

Lanctôt

et al. 2019

Journal of Dairy Science

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Bovine mammary gland involution, as a part of the reproductive cycle in dairy cows, is a very important remodeling transformation of the mammary gland for the subsequent lactation. There is considerable incentive to accelerate mammary gland involution to improve udder health, shorten the dry period, and simplify the management process by reducing dietary changes. The complex process of mammary involution is characterized by morphological changes in the epithelial cells and mammary tissue, changes in the composition of mammary secretions, and changes in the integrity of tight junctions. Involution is facilitated by elements of the immune system and several types of proteases and is coordinated by various types of hormones. This review first describes the involution process and then argues for the need to accelerate it. Last, this review focuses on various intervention methods for accelerating involution. Our aim is to provide a comprehensive overview of bovine mammary gland involution as well as potential techniques and new opinions for dry cow management.

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Effect of Pinealectomy on Prolactin, Testosterone and Luteinizing Hormone Concentration in Plasma of Bull Calves Exposed to 8 or 16 Hours of Light Per Day

Cited by 14 publications

References 27 publications

Does the circadian system regulate lactation?

Does the circadian system regulate lactation?

Daily Changes in Concentrations of Prolactin in Serum of Prepubertal Bulls Exposed to Short- or Long-Day Photoperiods

Invited review: Accelerating mammary gland involution after drying-off in dairy cattle

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