Pulsatile secretion pattern of growth hormone in turkeys: Effects of age and sex

Shaw, Snigdha; Bacon, Wayne L.; Vasilatos‐Younken, R.; Nestor, Karl E.

doi:10.1016/0016-6480(87)90045-1

Cited by 19 publications

(16 citation statements)

References 22 publications

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“…The pulsatile nature of GH in domestic poultry has now been well established (Buonomo et al, 1984;Vasilatos-Younken and Leach, 1986;Johnson et al, 1987;Vasilatos-Younken and Zarkower, 1987;Shaw et al, 1987), and specific components of the GH secretory profile, such as peak amplitude, are known to change significantly with age and concurrently, growth rate within lines of birds. Such potentially key components were not discernible within the limits of experimental design for the present study.…”

Section: Discussionmentioning

confidence: 96%

Relationship of Plasma Growth Hormone to Growth Within and Between Turkey Lines Selected for Differential Growth Rates

Vasilatos‐Younken

Nestor

1988

Poultry Science

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The ontogeny of plasma growth hormone (GH) was determined within and between genetically-related turkey lines selected for differential growth rates. Blood samples were obtained at weekly intervals from hatching through 195 days of age from male and female poults of a slow-growing, randombred line (RBC-2), representing the base population, and a fast-growing line selected over 20 generations from RBC-2 for increased 16-wk body weight (F). Growth rate of the F line exceeded that of RBC-2 during the very early (0 to 14 day) posthatch period (P less than .05), but was not different from that of the RBC-2 line by 77 to 195 days of age. Males of both lines were larger than females at all ages (P less than .05). Plasma GH increased from hatching until 2 wk of age and declined thereafter in both lines. Differences between overall plasma GH concentrations of the lines were not observed during the 0 to 14 day period, but concentrations were higher (P less than .05) in RBC-2 than F birds thereafter (21 to 195 days of age). Plasma GH concentrations initially (0 to 14 days) were higher in females than in males for both lines (P less than .05), but thereafter (21 to 195 days) declined more rapidly and averaged lower overall in females than in males (P less than .05). Correlations between measures of GH and growth rate within lines over age were strongly positive (r = .83 to .93; P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 96%

Relationship of Plasma Growth Hormone to Growth Within and Between Turkey Lines Selected for Differential Growth Rates

Vasilatos‐Younken

Nestor

1988

Poultry Science

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“…Two days prior to sampling, the right jugular vein of each bird was fitted with a Silastic Cannula (.7 mm, inside diameter and 1.4 mm, outside diameter), 4 as previously described by Shaw et al (1987). Before use, the cannula tubing was treated for 1 min with 2% tridodecylmethylammonium heparinate (TDMAC heparin complex; Polysciences, Warrington, PA) (Ford and Maurer, 1978).…”

Section: Methodsmentioning

confidence: 99%

“…With turkeys (Shaw et al, 1987), chickens (Buonomo et al, 1984;Vasilatos-Younken and Leach, 1986), and mammalian species, GH is secreted in a pulsatile manner. The overall plasma concentration of GH increases in fasted chickens and in chickens and turkeys with a chronically restricted feed intake.…”

Section: Introductionmentioning

confidence: 98%

Secretory Pattern of Growth Hormone, Insulin, and Related Metabolites in Growing Male Turkeys: Effects of Overnight Fasting and Refeeding

et al. 1990

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The effect of an overnight fast on the secretory profile of growth hormone (GH), insulin, and related metabolites [glucose, nonesterified fatty acids (NEFA) and triglycerides (TG)] was determined in two separate experiments with 8- and 9-wk-old male turkeys. Toms were provided feed ad libitum or were fasted 20 h prior to sampling. Blood samples (.6 to .7 mL) were collected every 10 min for 8 h from the toms showing a positive weight gain between cannulation and the initiation of the experiment. Overall and baseline, GH levels were higher for the fasted birds versus the fed birds. The GH peaks for the fasted birds were of shorter duration than those for the fed birds, but were more frequent. The plasma NEFA levels of the fasted birds were higher than those of the fed birds. Plasma TG was lower for the fasted than the fed group. Insulin, which was secreted in a pulsatile fashion, was lower for the fasted versus the fed birds. Fasting produced no change in plasma glucose. A separate group of fasted males was refed after 4 h of sampling; the plasma levels of GH, insulin, and metabolites returned to those observed in birds given feed ad libitum within 30 min of refeeding. There appeared to be no relation between the pulsatile release of GH and the circulating levels of NEFA.

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“…Like mammals, some birds exhibit sexual dimorph¬ isms in growth rates (20,21) and hepatic drug metabo¬ lism (22), but the role of endogenous GH in regulating these gender-specific functions is unknown. Although the preponderance of GH studies in chickens has been limited to a single gender, a few investigators have reported sex differences in plasma GH concentrations of chickens (23) and turkeys (21,24), but only lasting for a very short period in the young bird's life. In fact, adult plasma concentrations of GH in chickens and turkeys may decline to 5-10%, or even lower, of prepubertal levels (24)(25)(26).…”

mentioning

confidence: 98%

“…Although the preponderance of GH studies in chickens has been limited to a single gender, a few investigators have reported sex differences in plasma GH concentrations of chickens (23) and turkeys (21,24), but only lasting for a very short period in the young bird's life. In fact, adult plasma concentrations of GH in chickens and turkeys may decline to 5-10%, or even lower, of prepubertal levels (24)(25)(26). In the present study, we have inves¬ tigated the sexually dimorphic character of plasma GH levels in adult chickens when gender differences in hepatic drug metabolism are present (22).…”

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confidence: 98%

Testicular regulation of sexual dimorphisms in the ultradian profiles of circulating growth hormone in the chicken

Pampori

Shapiro²

1994

European Journal of Endocrinology

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Ultradian patterns in plasma growth hormone (GH) concentrations were determined in adult white Leghorn roosters, hens and capons. Serial blood samples were collected every 15 min over 8 h through surgically placed chronic indwelling right atrial catheters and assayed for GH content by a GH content by a homologous radioimmunoassay. In both sexes, GH levels fluctuated episodically, with peak and interpeak periods each lasting about 45 min in both roosters and hens. However, GH concentrations in the peaks and nadirs were 2.5-3.5 times greater in the plasma GH profiles of roosters as compared to hens, which resulted in roosters having higher mean GH concentrations. Caponizing completely feminized the episodic GH secretory profile. In contrast to chickens, the common sexually dimorphic feature in secretory GH profiles of mammals is the enhanced peak frequencing found in females.

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Pulsatile secretion pattern of growth hormone in turkeys: Effects of age and sex

Cited by 19 publications

References 22 publications

Relationship of Plasma Growth Hormone to Growth Within and Between Turkey Lines Selected for Differential Growth Rates

Relationship of Plasma Growth Hormone to Growth Within and Between Turkey Lines Selected for Differential Growth Rates

Secretory Pattern of Growth Hormone, Insulin, and Related Metabolites in Growing Male Turkeys: Effects of Overnight Fasting and Refeeding

Testicular regulation of sexual dimorphisms in the ultradian profiles of circulating growth hormone in the chicken

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