Development of a Radioimmunoassay for Plasma C-Peptide in Sheep: Kinetics of C-Peptide and Effects of Exogenous Growth Hormone and Glucose on Insulin and C-Peptide

An antiserum to purified bovine C-peptide was used to develop a sensitive radioimmunoassay for C-peptide in sheep. The assay was used to measure kinetics of C-peptide and insulin in non-pregnant and non-lactating sheep. Injected, purified C-peptide was distributed in pools comprising c. 11�4% of liveweight, the half time of C-peptide was estimated as 13�7 min and its clearance rate was c. 5 ml kg-I min-I. In lactating ewes exogenous recombinant bovine growth hormone (rebGH) increased both plasma insulin and C-peptide as did glucose challenge given before and during administration of rebGH. Estimates of insulin secretion rate in lactating ewes were c. 7 X 10-3 and 8�5 x 10-3 nmol kg-I min-I before and after glucose challenge prior to injections of rebGH. After 4 days of injection of rebGH, corresponding values were c. 8 x 10- 3 and 10 x 10-3 nmol min-I kg-I.

Download Full-text

The kinetics of bovine growth hormone folding are consistent with a framework model.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)61546-7 ◽

1987 ◽

Vol 262 (6) ◽

pp. 2590-2596

Author(s):

D.N. Brems ◽

S.M. Plaisted ◽

J.J. Dougherty ◽

T.F. Holzman

Keyword(s):

Growth Hormone ◽

Bovine Growth Hormone ◽

Framework Model ◽

Kinetics Of

Download Full-text

A review of bovine growth hormone

Canadian Journal of Animal Science ◽

10.4141/cjas94-027 ◽

1994 ◽

Vol 74 (2) ◽

pp. 167-201 ◽

Cited By ~ 77

Author(s):

Jeanne L. Burton ◽

Brian W. McBride ◽

Elliot Block ◽

David R. Glimm ◽

John J. Kennelly

Keyword(s):

Growth Hormone ◽

Mammary Gland ◽

Growth Factor ◽

Dairy Cows ◽

Milk Production ◽

Reproductive Efficiency ◽

Bovine Growth Hormone ◽

Insulin Like Growth Factor ◽

Factor I ◽

Exogenous Growth

Unprecedented numbers of technical papers, abstracts, and short communications have been published in the past decade regarding the effects of exogenous bovine growth hormone on milk production, health, and reproductive efficiency of treated dairy cows. In well-managed dairy herds, exogenous growth hormone increases milk production without altering normal variability in milk composition. This has held true regardless of dairy breed tested, geographical location studied, or feeding management system used. Also consistent across studies is the rapidity of the galactopoietic effect of administered bovine growth hormone, which arises from altered partitioning and use of post-absorptive nutrients and increased synthetic capacity of the mammary gland. Growth hormone and its associated peptide, insulin-like growth factor-I, are now known to provide chronic lipolytic, diabetogenic, and gluconeogenic signals to target tissues culminating in increased mammary gland availability of glucose and nonesterified fatty acids. Together with yet ill-defined effects on mammary secretory tissue, this homeorhetic control of metabolism elicited by exogenous growth hormone is so efficient that treated cows are not more susceptible to metabolic disorders than untreated cows. However, some studies have reported an increased frequency of mastitis in groups of treated cows. This has been attributed mainly to increased milk volume in the mammary glands of treated cows and no convincing data are available that show decreased mammary gland immunity as a result of growth hormone treatments. On the contrary, an expanding body of evidence implicates growth hormone as a key neuroendocrine factor that is required for immunological competence. Trends of decreased reproductive efficiency in cows treated with growth hormone have also been reported, but available data imply that this is probably an indirect effect via prolonged negative energy balance in cows treated in early lactation rather than a direct negative effect on estrous cycling via altered reproductive hormone profiles. The objectives of the present review are to bring into focus and summarize pertinent biological discoveries regarding the treatment of dairy cows with recombinant bovine growth hormone, and to explore areas where additional growth hormone research is needed or warranted. Key words: Growth hormone, somatotropin, dairy cows, insulin-like growth factor-I

Download Full-text

Short Stature Associated with Normal Growth Hormone and Decreased Somatomedin-C Concentrations: Response to Exogenous Growth Hormone

PEDIATRICS ◽

10.1542/peds.71.4.576 ◽

1983 ◽

Vol 71 (4) ◽

pp. 576-580

Author(s):

C. M. Bright ◽

A. D. Rogol ◽

A. J. Johanson ◽

R. M. Blizzard

Keyword(s):

Growth Hormone ◽

Short Stature ◽

Linear Growth ◽

Human Growth ◽

Normal Growth ◽

Metabolic Responses ◽

Exogenous Hormone ◽

Somatomedin C ◽

Exogenous Growth ◽

Before And After

Two prepubertal males with low somatomedin-C concentrations in their sera, but normal growth hormone concentrations, had positive metabolic responses when human growth hormone was administered. An accelerated velocity of growth accompanied the longterm administration of growth hormone. This response was dependent upon the administration of exogenous hormone inasmuch as linear growth was subnormal both before and after administration of growth hormone. The extreme short stature in these individuals may be secondary to a biologically inactive growth hormone molecule that is immunologically reactive or to a decreased dose responsiveness of the cells that produce somatomedin when exposed to the usual concentrations of endogenous growth hormone.

Download Full-text

Responses of Lactating Ewes to Exogenous Growth Hormone: Short- and Long-term Effects on Productivity and Tissue Utilization of Key Metabolites

Australian Journal of Biological Sciences ◽

10.1071/bi9880357 ◽

1988 ◽

Vol 41 (3) ◽

pp. 357 ◽

Cited By ~ 19

Author(s):

LD Sandles ◽

YX Sun ◽

AGC D'Cruz ◽

GH McDowell ◽

JM Gooden

Keyword(s):

Growth Hormone ◽

Milk Fat ◽

Milk Protein ◽

Bovine Growth Hormone ◽

Long Term Effects ◽

Exogenous Growth ◽

Short And Long Term

Responses to daily injections of bovine growth hormone (GH, 0�15 mg kg- 1 liveweight), beginning on day 10 of lactation, were measured in lactating ewes. Milk yields of GH-treated ewes increased soon after commencement of injections and continued to increase for some 25 days before reaching plateau levels. By comparison, yields of ewes injected with excipient (controls) decreased over the experiment. There was a tendency for contents of milk fat to be higher and milk protein to be lower for GH-treated than for control ewes during the first 15-20 days after injections were started.

Download Full-text

Na+/H+ exchange during an oral glucose challenge in patients with essential hypertension

Journal of Endocrinology ◽

10.1677/joe.0.1550443 ◽

1997 ◽

Vol 155 (3) ◽

pp. 443-450 ◽

Cited By ~ 5

Author(s):

M Tepel ◽

B Frye ◽

M Burchardt ◽

J Ruhwinkel ◽

C Spieker ◽

...

Keyword(s):

Blood Pressure ◽

Essential Hypertension ◽

Plasma Glucose ◽

Plasma Insulin ◽

Oral Glucose ◽

C Peptide ◽

Glucose Administration ◽

Glucose Challenge ◽

Exchange Activity

To determine the effects of an oral glucose challenge on cellular Na+/H+ exchange in vivo we measured plasma glucose concentrations, plasma insulin concentrations, plasma C-peptide concentrations, arterial blood pressure, cytosolic pH (pHi) and cellular Na+/H+ exchange in 24 patients with essential hypertension (HT) and 41 age-matched healthy normotensive control subjects (NT) during a standardized oral glucose tolerance test. Under resting conditions, the plasma glucose concentrations, plasma insulin concentrations, plasma C-peptide concentrations and Na+/H+ exchange activity were significantly higher in HT compared with NT (P < 0.05 in each case). A significant increase in lymphocytic Na+/H+ exchange activity was only seen in NT (resting 0 h: (4.23 +/- 0.2) x 10(-3) pHi/s; mean +/- S.E.M.; 1 h after glucose administration: (6.00 +/- 0.56) x 10(-3) pHi/s; 2 h after glucose administration: (6.65 +/- 0.64) x 10(-3) pHi/s; P = 0.0003 by Friedman's two-way ANOVA), but not in HT (resting 0 h: (6.07 +/- 0.36) x 10(-3) pHi/s; 1 h after glucose administration: (6.72 +/- 1.02) x 10(-3) pHi/s; 2 h after glucose administration: (6.71 +/- 0.62) x 10(-3) pHi/s; P = 0.7470). During an oral glucose challenge the systolic (P < 0.0001) and diastolic (P < 0.0001) blood pressure significantly decreased in HT but not in NT. Essential hypertension shows abnormal in vivo regulation of Na+/H+ exchange and blood pressure following oral glucose intake.

Download Full-text

Short-term Effects of Exogenous Growth Hormone: Effects on Milk Production and Utilization of Nutrients in Muscle and Mammary Tissues of Lactating Ewes

Australian Journal of Biological Sciences ◽

10.1071/bi9880279 ◽

1988 ◽

Vol 41 (3) ◽

pp. 279 ◽

Cited By ~ 11

Author(s):

GH McDowell ◽

D Leenanuruksa ◽

P Niumsup ◽

JM Gooden ◽

JG van der Walt ◽

...

Keyword(s):

Growth Hormone ◽

Milk Production ◽

Milk Fat ◽

Fat Content ◽

Bovine Growth Hormone ◽

Short Term ◽

Exogenous Growth ◽

Hormone Effects ◽

Leg Muscle ◽

Mammary Tissues

Exogenous bovine growth hormone at a dose of 0�1 mg kg-1liveweight increased yields of milk and milk constituents and milk fat content when injected over 5 days into ewes in mid-lactation. These changes in milk production were associated with changes in the supply to, and utilization of, nutrients by leg muscle and mammary tissues.

Download Full-text

Kinetics of the Somatomedin C/Insulin-Like Growth Factor I: Response to Exogenous Growth Hormone (GH) in GH-Deficient Children *

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem-54-5-986 ◽

1982 ◽

Vol 54 (5) ◽

pp. 986-990 ◽

Cited By ~ 20

Author(s):

SANDRA L. BLETHEN ◽

WILLIAM H. DAUGHADAY ◽

VIRGINIA V. WELDON

Keyword(s):

Growth Hormone ◽

Growth Factor ◽

Insulin Like Growth Factor ◽

Somatomedin C ◽

Factor I ◽

Exogenous Growth ◽

Growth Factor I ◽

Kinetics Of

Download Full-text

ANALYSIS OF THE BIPHASIC ACTION OF GROWTH HORMONE IN VITRO ON THE RAT DIAPHRAGM

Acta Endocrinologica ◽

10.1530/acta.0.057s019 ◽

1968 ◽

Vol 57 (3_Suppl) ◽

pp. S19-S35 ◽

Cited By ~ 9

Author(s):

Å. Hjalmarson

Keyword(s):

Growth Hormone ◽

Actinomycin D ◽

Accumulation Rate ◽

Inhibitory Effect ◽

Bovine Growth Hormone ◽

Rat Diaphragm ◽

Dual Nature ◽

Hypophysectomized Rats ◽

D 20

ABSTRACT In vitro addition of bovine growth hormone (GH) to intact hemidiaphragms from hypophysectomized rats has previously been found to produce both an early stimulatory effect lasting for 2—3 hours and a subsequent late inhibitory effect during which the muscle is insensitive to further addition of GH (Hjalmarson 1968). These effects on the accumulation rate of α-aminoisobutyric acid (AIB) and D-xylose have been further studied. In presence of actinomycin D (20 μg/ml) or puromycin (100 μg/ml) the duration of the stimulatory effect of GH (25 μg/ml) was prolonged to last for at least 4—5 hours and the late inhibitory effect was prevented. Similar results were obtained when glucose-free incubation medium was used. Preincubation of the diaphragm at different glucose concentrations (0—5 mg/ml) for 3 hours did not change the GH sensitivity. Addition of insulin at start of incubation could not prevent GH from inducing its late inhibitory effect, while dexamethasone seemed to potentiate this effect of GH. Furthermore, adrenaline was found to decrease the uptake of AIB-14C and D-xylose-14C in the diaphragm, but not to change the sensitivity of the muscle to GH. Preincubation of the diaphragm for 3 hours with puromycin in a concentration of 200 μg/ml markedly decreased the subsequent basal uptake of both AIB-14C and D-xylose-14C, in the presence of puromycin, and abolished the stimulatory effect of GH on the accumulation of AIB-14C. However, the effect of GH on the accumulation of D-xylose-14C was unchanged. The present observations are discussed and evaluated in relation to various mechanisms of GH action proposed to explain the dual nature of the hormone.

Download Full-text

THE EFFECT OF THE PROGESTOGEN ETHYNODIOL DIACETATE ON GLUCOSE, INSULIN, AND GROWTH HORMONE AFTER SIX MONTHS TREATMENT

Acta Endocrinologica ◽

10.1530/acta.0.0700373 ◽

1972 ◽

Vol 70 (2) ◽

pp. 373-384 ◽

Cited By ~ 22

Author(s):

W. N. Spellacy ◽

W. C. Buhi ◽

S. A. Birk

Keyword(s):

Growth Hormone ◽

Blood Glucose ◽

Plasma Insulin ◽

Tolerance Test ◽

Metabolic Effects ◽

Oral Glucose ◽

Hormone Levels ◽

Glucose Levels ◽

Ethynodiol Diacetate ◽

Tolerance Curve

ABSTRACT Seventy-one women were treated with a daily dose of 0.25 mg of the progestogen ethynodiol diacetate. They were all tested with a three-hour oral glucose tolerance test before beginning the steroid and then again during the sixth month of use. Measurements were made of blood glucose and plasma insulin and growth hormone levels. There was a significant elevation of the blood glucose levels after steroid treatment as well as a deterioration in the tolerance curve in 12.9% of the women. The plasma insulin values were also elevated after drug treatment whereas the fasting ambulatory growth hormone levels did not significantly change. There was a significant association between the changes in glucose and insulin levels and the subject's age, control weight, or weight gain during treatment. The importance of considering the metabolic effects of the progestogen component of oral contraceptives is stressed.

Download Full-text